You searched for +publisher:"Georgia Tech" +contributor:("Newman, Andrew"). Showing records 1 – 29 of 29 total matches.
1. Sun, Wei-Fang. Detecting deep tectonic tremor in Taiwan using dense arrays.
▼ Deep tectonic tremor has been observed in major subduction zones, strike-slip faults, inland faulting systems, and arc-continent collision environments around the Pacific Rim. However, detailed space-time evolution of its source locations remains enigmatic because of difficulties in detecting and locating tremor accurately. In 2011, we installed two dense, small-aperture seismic arrays aiming to detect ambient tremor source beneath southern Central Range in Taiwan. We recorded continuous waveforms for a total of 134 days, including tremor triggered by the great 2011 Mw9.0 Tohoku earthquake. We use the broadband frequency-wavenumber beamforming and the moving-window grid-search methods to compute array parameters for detecting seismic signals. The obtained array parameters closely match both relocated local earthquakes and triggered tremor bursts located by an envelope cross-correlations method, indicating the robustness of our array technique. We identify tremor signals with coherent waveforms and deep incidence angles and detect tremor for 44 days among the 134-day study period. The total duration is 1,481-minute, which is 3-6 times more than that detected by the envelope cross-correlations method. In some cases, we observe rapid tremor migration with a speed at the order of 40-50 km/hour that is similar to the speed of fast tremor migration along-dip on narrow streaks in Japan and Cascadia. Our results suggest that dense array techniques are capable of capturing detailed spatiotemporal evolutions of tremor behaviors in southern Taiwan. Advisors/Committee Members: Peng, Zhigang (advisor), Newman, Andrew V. (committee member), Huber, Christian (committee member).
Sun, Wei-Fang. "Detecting deep tectonic tremor in Taiwan using dense arrays." 2014. Masters Thesis, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/54251.
Sun, Wei-Fang. "Detecting deep tectonic tremor in Taiwan using dense arrays." 2014. Web. 23 Apr 2019.
Sun W. Detecting deep tectonic tremor in Taiwan using dense arrays. [Internet] [Masters thesis]. Georgia Tech; 2014. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/54251.
2. Chao, Tzu-Kai Kevin. Temporal changes of shear wave velocity and anisotropy in the shallow crust induced by the 10/22/1999 m6.4 Chia-yi, Taiwan earthquake.
▼ Temporal changes of seismic velocity and anisotropy in the shallow crust are quantified using local earthquakes recorded at a 200-m-deep borehole station CHY in Taiwan. This station is located directly above the hypocenter of the 10/22/1999, M6.4 Chia-Yi earthquake. Three-component seismograms recorded at this station show clear direct (up-going) and surface-reflected (down-going) P- and S-waves, and S-wave splitting signals. The two-way travel times in the top 200 m is obtained by measuring the time delays between the up-going and down-going waves in the auto-correlation function. The S-wave travel times measured in two horizontal components increase by ~1-2% at the time of Chia-Yi main shock, and followed by a logarithmic recovery, while the temporal changes of S-wave splitting and P-wave are less than 1% and are not statistically significant. We obtain similar results by grouping earthquakes into clusters according to their locations and waveform similarities. This suggests that the observed temporal changes are not very sensitive to the seismic ray path below CHY, but are mostly controlled by the variation of material property in the top 200 m of the crust. We propose that strong ground motions of the Chia-Yi main shock cause transient openings of fluid-filled microcracks and increases the porosity in the near-surface layers, followed by a relatively long healing process. Because we observe no clear changes in the shear wave anisotropy, we infer that the co-seismic damages do not have a preferred orientation. Our results also show a gradual increase of time delays for both the fast and slow S-waves in the previous 7 years before the Chia-Yi main shock. Such changes might be caused by variations of water table, sediment packing or other surficial processes. Advisors/Committee Members: Peng, Zhigang (Committee Chair), Assimaki, Dominic (Committee Member), Newman, Andrew V. (Committee Member).
Chao, Tzu-Kai Kevin. "Temporal changes of shear wave velocity and anisotropy in the shallow crust induced by the 10/22/1999 m6.4 Chia-yi, Taiwan earthquake." 2009. Masters Thesis, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/28088.
Chao, Tzu-Kai Kevin. "Temporal changes of shear wave velocity and anisotropy in the shallow crust induced by the 10/22/1999 m6.4 Chia-yi, Taiwan earthquake." 2009. Web. 23 Apr 2019.
Chao TK. Temporal changes of shear wave velocity and anisotropy in the shallow crust induced by the 10/22/1999 m6.4 Chia-yi, Taiwan earthquake. [Internet] [Masters thesis]. Georgia Tech; 2009. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/28088.
3. Telling, Jennifer Whitney. An experimental evaluation of the role of water vapor and collisional energy on ash aggregation in explosive volcanic eruptions.
▼ Eruption dynamics are sensitive to ash aggregation, and ash aggregates (e.g. accretionary lapilli) are commonly found in eruptive deposits, yet few experiments have been conducted on aggregation phenomena using natural materials. Experiments were developed to produce a probabilistic relationship for the efficiency of ash aggregation with respect to particle size, collision kinetic energy and atmospheric water vapor. The laboratory experiments were carried out in an enclosed tank designed to allow for the control of atmospheric water vapor. A synthetic ash proxy, ballotini, and ash from the 2006 eruption of Tungurahua, in Ecuador, were examined for their aggregation potential. Image data was recorded with a high speed camera and post-processed to determine the number of collisions, energy of collisions and probability of aggregation. Aggregation efficiency was dominantly controlled by collision kinetic energy and little to no dependence on atmospheric water vapor was seen in the range of relative humidity conditions tested, 20 to 80%. Equations governing the relationships between aggregation efficiency and collision kinetic energy and the related particle Stokes number, respectively, were determined for implementation into large scale numerical volcanic models. Advisors/Committee Members: Dufek, Josef (Committee Chair), Nenes, Athanasios (Committee Member), Newman, Andrew (Committee Member).
Telling, Jennifer Whitney. "An experimental evaluation of the role of water vapor and collisional energy on ash aggregation in explosive volcanic eruptions." 2011. Masters Thesis, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/43674.
Telling, Jennifer Whitney. "An experimental evaluation of the role of water vapor and collisional energy on ash aggregation in explosive volcanic eruptions." 2011. Web. 23 Apr 2019.
Telling JW. An experimental evaluation of the role of water vapor and collisional energy on ash aggregation in explosive volcanic eruptions. [Internet] [Masters thesis]. Georgia Tech; 2011. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/43674.
4. Meng, Xiaofeng. Systematic study of earthquake triggering using microearthquakes detected by the matched filter technique.
▼ Earthquakes can be promoted or inhibited by surprisingly small stress perturbations, known as earthquake triggering. The stress perturbations can stem from various natural and anthropogenic processes. The most common stress transfer mechanisms are from other earthquakes, including static stress redistribution caused by permanent fault slip (i.e., static triggering) and dynamic stress carried by passing seismic waves (i.e., dynamic triggering). However, currently seismologists are still debating on whether static or dynamic stresses are more important in triggering earthquakes in near field. Moreover, earthquakes can be triggered by other natural and anthropogenic processes, such as subsurface fluid movement, solid earth tides and wastewater disposal. Study of earthquake triggering has the potential for helping us better understand the physics of the earthquake nucleation, and ultimately, improve seismic hazard assessment and mitigation by forecasting where the next "domino" may fall. However, one major impediment in triggering study is the incompleteness of earthquake catalogs, mainly due to the low signal-to-noise ratio of small earthquakes and masking from the coda waves of larger events. To overcome this, I developed a GPU-based matched filter technique to automatically detect earthquakes through collaborations with computer scientists at Georgia Tech. If two earthquakes occur very close to each other and have similar fault slip, the resulting waveforms recorded at the same station must be very similar. Hence, this technique uses previously identified earthquakes as templates and automatically scans through continuous recordings to detect new events that have high waveform similarities to the templates. The matched filter technique exhibits regular computation and memory access patterns and is mostly data parallel, which makes it an ideal fit for GPU processing. The GPU algorithm cross-correlates multiple templates with the continuous data in parallel and achieves ~40 times speedup over a single CPU card. By using 30 GPU cards on supercomputing cluster 'Keeneland' at the Oak Ridge National Lab, the GPU-based method achieves up to ~1000 times speedup over a single CPU. Based on many more microearthquakes detected by the matched filter technique, I was able to investigate a wide spectrum of earthquake triggering mechanisms, including earthquakes triggering associated with static and dynamic stress changes from large nearby earthquakes, atmospheric pressure changes and deep aseismic creep. First, I found clear evidences of 'stress shadow', a shut-down of seismicity due to negative static stress changes along Parkfield section of the San Andreas Fault following the 2003 M6.5 San Simeon earthquake. More importantly, the seismicity rate increased near the epicentral region of the future 2004 M6.0 Parkfield earthquake, where the static stress changes are positive, suggesting that the 2004 Parkfield earthquake may be delayed triggered by the 2003 San Simeon earthquake. Second, by examining the temporal evolution of… Advisors/Committee Members: Peng, Zhigang (advisor), Newman, Andrew (committee member), Dufek, Josef (committee member), Huber, Christian (committee member), Xie, Yao (committee member).
Meng, Xiaofeng. "Systematic study of earthquake triggering using microearthquakes detected by the matched filter technique." 2015. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/55512.
Meng, Xiaofeng. "Systematic study of earthquake triggering using microearthquakes detected by the matched filter technique." 2015. Web. 23 Apr 2019.
Meng X. Systematic study of earthquake triggering using microearthquakes detected by the matched filter technique. [Internet] [Doctoral dissertation]. Georgia Tech; 2015. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/55512.
5. Telling, Jennifer Whitney. Microphysical processes of volcanic ash aggregation and their implications for volcanic eruption dynamics.
▼ Although numerous hazard models exist to assess possible ash fallout from explosive volcanic eruptions around the world, these models frequently neglect to consider ash aggregation or use a simple percent proxy to represent aggregation, without considering the varying processes at work throughout the volcanic flow. Eruption dynamics are sensitive to ash aggregation, and ash aggregates are commonly found in eruptive deposits, yet few experiments have been conducted on aggregation phenomena using natural materials. In this work, experiments were developed to produce both probabilistic and process-based relationships for the efficiency of ash aggregation with respect particle size, collision kinetic energy, atmospheric water vapor and residence time. A synthetic ash proxy, ballotini, and ash from the 2006 eruption of Tungurahua, Ecuador, and the 1980 eruption of Mount St. Helens, WA, were examined for their aggregation potential. Two aggregation regimes, wet and dry, were identified based on their potential for aggregation. The wet flow regime occurs when particles are circulated in high relative humidity environments long enough to develop a water layer with a thickness that exceeds the particle roughness scale. Hydrodynamic forces control aggregation in the wet flow regime. The dry flow regime includes particles in low relative humidity environments as well as those that circulate too briefly in high humidity environments to fully develop a water layer. Electrostatic forces control aggregation in the dry flow regime. Aggregation efficiency in both regimes was dominantly controlled by collision kinetic energy; however, this effect is significantly dampened in the wet flow regime. Equations governing the relationships between aggregation efficiency, collision kinetic energy and the related forcings in the wet or dry flow regimes have been developed for implementation into large-scale numerical volcanic models. The results of this experimental work have been developed into a probability distribution that has been integrated and incorporated into a multifluid numerical model. The numerical simulation was tested on a range of explosive depths and overpressure estimates from the 1790 eruption of Kilauea volcano, HI. The model output was compared to field data collected on the deposit thickness moving away from the source and the distribution, including both size and density, of aggregates. The mass fraction of ash removed from the eruption column in the form of aggregates was also calculated to examine how efficiently aggregation processes remove ash throughout the eruption. Cumulatively, the work presented here furthers our understanding of aggregation processes and the role they play in volcanic eruptions. Advisors/Committee Members: Dufek, Josef (advisor), Newman, Andrew (committee member), Nenes, Athanasios (committee member), Wray, James (committee member), Huber, Christian (committee member).
Telling, Jennifer Whitney. "Microphysical processes of volcanic ash aggregation and their implications for volcanic eruption dynamics." 2013. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/52925.
Telling, Jennifer Whitney. "Microphysical processes of volcanic ash aggregation and their implications for volcanic eruption dynamics." 2013. Web. 23 Apr 2019.
Telling JW. Microphysical processes of volcanic ash aggregation and their implications for volcanic eruption dynamics. [Internet] [Doctoral dissertation]. Georgia Tech; 2013. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/52925.
6. Benage, Mary Catherine. The thermal evolution and dynamics of pyroclasts and pyroclastic density currents.
▼ The thermal evolution of pyroclastic density currents (PDCs) is the result of entrainment of ambient air, particle concentration, and initial eruptive temperature, which all impact PDC dynamics and their hazards, such as runout distance. The associated hazards and opaqueness of PDCs make it impossible for in-situ entrainment efficiencies or concentration measurements that would provide critical information on the thermal evolution and physical processes of PDCs. The thermal evolution of explosive eruptive events such as volcanic plumes and pyroclastic density currents (PDCs) is reflected in the textures of the material they deposit. A multiscale model is developed to evaluate how the rinds of breadcrust bombs can be used as a unique thermometer to examine the thermal evolution of PDCs. The multiscale, integrated model examines how bubble growth, pyroclast cooling, and dynamics of PDC and projectile pyroclasts form unique pyroclast morphology. Rind development is examined as a function of transport regime (PDC and projectile), transport properties (initial current temperature and current density), and pyroclast properties (initial water content and radius). The model reveals that: 1) rinds of projectile pyroclasts are in general thicker and less vesicular than those of PDC pyroclasts; 2) as the initial current temperature decreases due to initial air entrainment, the rinds on PDC pyroclasts progressively increase in thickness; and 3) rind thickness increases with decreasing water concentration and decreasing clast radius. Therefore, the modeled pyroclast's morphology is dependent not only on initial water concentration but also on the cooling rate, which is determined by the transport regime. The developed secondary thermal proxy is then applied to the 2006 PDCs from the Tungurahua eruption to constrain the entrainment efficiency and thermal evolution of PDCs. A three-dimensional multiphase Eulerian-Eulerian-Lagrangian (EEL) model is coupled to topography and field data such as paleomagnetic data and rind thicknesses of collected pyroclasts to study the entrainment efficiency and thus the thermal history of PDCs at Tungurahua volcano, Ecuador. The modeled results that are constrained with observations and thermal proxies demonstrate that 1) efficient entrainment of air to the upper portion of the current allows for rapid cooling, 2) the channelized pyroclastic density currents may have developed a stable bed load region that was inefficient at cooling and 3) the PDCs had temperatures of 600-800K in the bed load region but the upper portion of the currents cooled down to ambient temperatures. The results have shown that PDCs can be heterogeneous in particle concentration, temperature, and dynamics and match observations of PDCs down a volcano and the thermal proxies. Lastly, the entrainment efficiencies of PDCs increases with increasing PDC temperature and entrainment varies spatially and temporally. Therefore, the assumption of a well-mixed current with a single entrainment coefficient cannot fully solve the thermal… Advisors/Committee Members: Dufek, Josef (advisor), Huber, Christian (committee member), Newman, Andrew (committee member), Peng, Zhigang (committee member), Wright, Heather (committee member).
Benage, Mary Catherine. "The thermal evolution and dynamics of pyroclasts and pyroclastic density currents." 2015. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/53962.
Benage, Mary Catherine. "The thermal evolution and dynamics of pyroclasts and pyroclastic density currents." 2015. Web. 23 Apr 2019.
Benage MC. The thermal evolution and dynamics of pyroclasts and pyroclastic density currents. [Internet] [Doctoral dissertation]. Georgia Tech; 2015. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/53962.
7. Mohammed, Fahad. Physical modeling of tsunamis generated by three-dimensional deformable granular landslides.
▼ Tsunamis are gravity water waves that are generated by impulsive disturbances such as submarine earthquakes, landslides, volcanic eruptions, underwater explosions or asteroid impacts. Submarine earthquakes are the primary tsunami source, but landslides may generate tsunamis exceeding tectonic tsunamis locally, in both wave and runup heights. The field data on landslide tsunami events are limited, in particular regarding submarine landslide dynamics and wave generation. Tsunamis generated by three-dimensional deformable granular landslides are physically modeled in the NEES (Network of Earthquake Engineering Simulation) 3D tsunami wave basin (TWB) at Oregon State University in Corvallis, Oregon. A novel pneumatic landslide tsunami generator is deployed to simulate natural landslide motion on a hill slope. The instrumentation consists of various underwater, above water and particle image velocimetry (PIV) cameras, numerous wave and runup gauges and a multi-transducer acoustic array (MTA). The subaerial landslide shape and kinematics on the hill slope and the surface elevation of the offshore propagating tsunami wave and runup on the hill slope are measured. The evolution of the landslide front velocity, maximum landslide thickness and width are obtained along the hill slope. The landslide surface velocity distribution is obtained from the PIV analysis of the subaerial landslide motion. The shape and the size of the submarine landslide deposit are measured with the MTA. Predictive equations are obtained for the tsunami wave amplitude, wave period and wavelength in terms of the non-dimensional landslide parameters. The generated 3D tsunami waves propagate away from the landslide source as radial wave fronts. The amplitudes of the leading tsunami waves decay away from the landslide source in radial and angular direction. The wave celerity of the leading tsunami wave may be approximated by the solitary wave speed while the trailing waves are slower due to the dispersion effects. The energy conversion rate between the landslide and the generated wave is estimated. The observed waves are weakly non-linear in nature and span from shallow water to deep water depth regime. The unique experimental data serves the validation and advancement of numerical models of tsunamis generated by landslides. The obtained predictive equations facilitate initial rapid tsunami hazard assessment and mitigation. Advisors/Committee Members: Dufek, Josef (committee member), Haas, Kevin (committee member), Newman, Andrew (committee member), Webster, Donald (committee member), Work, Paul (committee member), Fritz, Hermann.
Mohammed, Fahad. "Physical modeling of tsunamis generated by three-dimensional deformable granular landslides." 2010. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/37152.
Mohammed, Fahad. "Physical modeling of tsunamis generated by three-dimensional deformable granular landslides." 2010. Web. 23 Apr 2019.
Mohammed F. Physical modeling of tsunamis generated by three-dimensional deformable granular landslides. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/37152.
8. Liu, Lei. Heat transfer from a convecting crystallizing, replenished magmatic sill and its link to seafloor hydrothermal heat output.
▼ Hydrothermal systems at oceanic spreading centers play an important role in the composition of seawater, the formation of ore deposits, the support of microbial and macrofaunal ecosystems, and even for the development of life on early earth. These circulation systems are driven by heat transport from the underlying magma chamber, where latent heat of crystallization and sensible heat from cooling are transferred by vigorous, high Rayleigh number convection through a thin conductive boundary layer. The traditional study of magmatic-hydrothermal systems is primarily based on the time-series observation, which takes the form of repeat visits, continuous offline monitoring by autonomous instruments, or continuous online monitoring by instruments with satellite or cable links to shore. Although a number of studies have deployed autonomous monitoring instruments at vents and around mid-ocean ridges to investigate geophysical and hydrothermal processes, the data are still rather limited and a comprehensive understanding of magma-hydrothermal processes at oceanic spreading centers is lacking. Numerical modeling needs to be employed to elucidate the dynamic behavior of magmatic hydrothermal systems and for testing completing hypotheses in these complex, data-poor environments. In this dissertation, I develop a mathematical framework for investigating heat transport from a vigorously convecting, crystallizing, cooling, and replenished magma chamber to an overlying hydrothermal system at an oceanic spreading center. The resulting equations are solved numerically using MATLAB. The simulations proceed step-by-step to investigate several different aspects of the system. First, I consider a hydrothermal system driven by convection, cooling and crystallization in a ~ 100 m thick basaltic magma sill representing an axial magma chamber (AMC) at an oceanic spreading center. I investigate two different crystallization scenarios, crystal-suspended and crystal-settling, and consider both un-replenished and replenished AMCs. In cases without magma replenishment, the simulation results for crystals-suspended models show that heat output and the hydrothermal temperature decrease rapidly and crystallinity reaches 60% in less than ten years. In crystals-settling models, magma convection may last for decades, but decreasing heat output and hydrothermal temperatures still occur on decadal timescales. When magma replenishment is included, the magmatic heat flux approaches steady state on decadal timescales, while the magma body grows to double its original size. The rate of magma replenishment needed ranges between 5 x 10⁵ and 5 x 10⁶ m³/yr, which is somewhat faster than required for seafloor spreading, but less than fluxes to some terrestrial and subseafloor volcanoes on similar timescales. The heat output from a convecting, crystallizing, replenished magma body that is needed to drive observed high-temperature hydrothermal systems is consistent, with gabbro glacier models of crustal production at mid-ocean ridges. Secondly, I… Advisors/Committee Members: Lowell, Robert (Committee Chair), Dufek, Josef (Committee Member), Germanovich, Leonid (Committee Member), Newman, Andrew (Committee Member), Taillefert, Martial (Committee Member).
Liu, Lei. "Heat transfer from a convecting crystallizing, replenished magmatic sill and its link to seafloor hydrothermal heat output." 2010. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/37215.
Liu, Lei. "Heat transfer from a convecting crystallizing, replenished magmatic sill and its link to seafloor hydrothermal heat output." 2010. Web. 23 Apr 2019.
Liu L. Heat transfer from a convecting crystallizing, replenished magmatic sill and its link to seafloor hydrothermal heat output. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/37215.
9. Williamson, Amy L. Improved understanding of extent and size of tsunamigenic earthquakes through geodetic and tsunami datasets.
▼ This dissertation seeks to constrain the rupture size and magnitude of tsunamigenic earthquakes through the inclusion of data from both traditional geodetic instruments and recently deployed open-ocean tsunami gauges. First, I assess the sensitivity of the subduction zone model space to geodetic and tsunami waveform data. This provides a picture of where we can and cannot resolve rupture models when data is limited. It also highlights the issues that can ensue if poorly constrained models are used to study earthquakes. Second, I conduct an event-based joint inversion incorporating both geodetic and tsunami data for the 2015 Illapel, Chile earthquake. This includes merging codes for tsunami propagation, fault deformation, and linear inversions. The result of the joint inversion is a model space that is not only resolved near the coastline where geodetic data exists, but also near the trench where tsunami data is significantly more sensitive. The third component of this dissertation is an analysis of the feasibility of open-ocean data for rapid source inversions. This builds on current tsunami warning center methodologies but with a focus on the time constricted scenarios of a near-field warning from a local tsunami source. Here I analyze four different regions for their tsunamigenic potential as well as their potential to have instrumentation that will provide enough lead time during a local event to record data that is meaningful for disaster management and hazard warnings. The combination of these different aspects of tsunami-geodetic joint inversions illustrates both the improved model resolution and understanding of what was once a poorly constrained problem. Advisors/Committee Members: Newman, Andrew V. (advisor), Peng, Zhigang (committee member), Cummins, Phil (committee member), Fritz, Hermann (committee member), Ferrier, Ken (committee member).
Williamson, Amy L. "Improved understanding of extent and size of tsunamigenic earthquakes through geodetic and tsunami datasets." 2018. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/59811.
Williamson, Amy L. "Improved understanding of extent and size of tsunamigenic earthquakes through geodetic and tsunami datasets." 2018. Web. 23 Apr 2019.
Williamson AL. Improved understanding of extent and size of tsunamigenic earthquakes through geodetic and tsunami datasets. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/59811.
10. Li, Zefeng. Fault zone imaging and earthquake detection with dense seismic arrays.
▼ Natural earthquakes occur on faults. The relationship between fault zone structures and earthquake behaviors remains one of the most interesting problems in seismology. As an important tool to detect earthquakes and image the Earth's interior, seismic arrays have been widely used since the 1960s. Recordings from closely spaced uniform seismometers improved imaging resolution of the Earth's interior and enhanced detection of small-magnitude earthquakes. However, such an increase in data size also poses a challenge in the way that we used to handle and processing seismic data. Visual inspection and manual selection become less practical and sometimes impossible. My PhD research focuses on obtaining high-resolution seismic properties (e.g., seismic anisotropy and velocity contrast) along major fault zones in California and Turkey, and detecting seismic events/phases multi-scale dense seismic arrays. To process large-size seismic data, I developed several tools to automatically pick P, S and fault zone head waves. Using recently emerging ultra-dense arrays, I proposed a new metric, termed local similarity, to detect weak microseismic signals that are barely above noise level. These studies share the same feature, i.e., using automatic techniques to extract earthquake and structure information from big seismic data recorded by dense or ultra dense arrays. The results are expected to provide valuable information on fault zone structures and microseismic behaviors. The tools developed in these studies can be applied to a wide range of research topics. Advisors/Committee Members: Peng, Zhigang (advisor), Newman, Andrew (committee member), Dufek, Josef (committee member), Ferrier, Ken (committee member), McClellan, James (committee member).
Li, Zefeng. "Fault zone imaging and earthquake detection with dense seismic arrays." 2017. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/60154.
Li, Zefeng. "Fault zone imaging and earthquake detection with dense seismic arrays." 2017. Web. 23 Apr 2019.
Li Z. Fault zone imaging and earthquake detection with dense seismic arrays. [Internet] [Doctoral dissertation]. Georgia Tech; 2017. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/60154.
11. Aiken, Chastity. Triggered earthquakes and tremor: Their characteristics and physical mechanisms.
▼ Dynamic triggering of earthquakes is investigated and compared among three geothermal/volcanic regions of California, and dynamic triggering of tremor is investigated and compared among several strike-slip faults in the Western Hemisphere. The characteristics of the triggering waves - amplitude, frequency, and incidence of the triggering waves on faults – are explored. Results indicate that for earthquake triggering, peak dynamic stress (amplitude) appears to be the primary controlling factor. On the other hand, tremor triggering is controlled by amplitude, frequency, and incidence of the seismic waves on the fault. In addition, earthquake triggering primarily occurs in geothermal regions with extensional tectonics, while tremor triggering occurs predominately in compressional or transpressional tectonic environments. A geothermal region's susceptibility to triggering by external stressing is found to be proportional to its background activity rate. However, tremor triggering appears to occur more often than earthquake triggering. The observation that tremor is triggered more often than earthquakes could be a reflection of a fault being weaker at depth (where tremor occurs) than in the shallower crust (where earthquakes occur). That is, tremor may be more easily triggered due to a fault having low effective stress, pressurized fluids, and/or a perpetual state of near-criticality at depths where tremor occurs. Potential research directions that further explore dynamic triggering of earthquakes and tremor are discussed. Advisors/Committee Members: Peng, Zhigang (advisor), Newman, Andrew (advisor), Dufek, Josef (advisor), Huber, Christian (advisor), Dovrolis, Constantine (advisor).
Aiken, Chastity. "Triggered earthquakes and tremor: Their characteristics and physical mechanisms." 2015. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/55493.
Aiken, Chastity. "Triggered earthquakes and tremor: Their characteristics and physical mechanisms." 2015. Web. 23 Apr 2019.
Aiken C. Triggered earthquakes and tremor: Their characteristics and physical mechanisms. [Internet] [Doctoral dissertation]. Georgia Tech; 2015. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/55493.
12. Foy, Travis A. Quaternary faulting in Clayton Valley, Nevada: implications for distributed deformation in the Eastern California shear zone-walker lane.
▼ The eastern California shear zone (ECSZ) and Walker Lane belt represent an important inland component of the Pacific-North America plate boundary. Current geodetic data indicate accumulation of transtensional shear at a rate of ~9.2 ± 0.3 mm/yr across the region, more than double the total geologic rate (<3.5 mm/yr) for faults in the northern ECSZ over the late Pleistocene [Bennett et al., 2003, Kirby et al., 2006, Lee et al., 2009, Frankel et al., 2007]. Unraveling the strain puzzle of the Walker Lane is therefore essential to understanding both how deformation is distributed through the lithosphere along this transtensional part of the Pacific-North America plate boundary and how the plate boundary is evolving through time. The observed mismatch between geodetic and geologic slip rates in the central Walker Lane is characteristic of other active tectonic settings, including the nearby Mojave segment of the ECSZ [Oskin et al., 2008] and the Altyn Tagh fault in China [Cowgill, 2007]. In each case, lack of fault slip data spanning multiple temporal and spatial scales hinders interpretation of fault interactions and their implications for lithospheric dynamics. The discrepancy between geodetic and geologic slip rates in the central Walker Lane indicates that if strain rates have remained constant since the late Pleistocene [e.g. Frankel et al., in press], then the "missing" strain is distributed on structures other than the two major dextral faults at this latitude (Death Valley-Fish Lake Valley fault and White Mountains fault). Otherwise the region could presently be experiencing a strain transient similar to that of the nearby Mojave section of the ECSZ [e.g., Oskin et al., 2008], or the rate of strain accumulation could actually increasing over the late Pleistocene [e.g. Reheis and Sawyer, 1997; Hoeft and Frankel, 2010]. The Silver Peak-Lone Mountain extensional complex (SPLM), to which the Clayton Valley faults belong, is the prime candidate to account for the "missing" strain. The down-to-the-northwest orientation of the SPLM faults makes them the most kinematically suitable structures to accommodate the regional pattern of NW-SE dextral shear. We use differential GPS to measure fault offset and terrestrial cosmogenic nuclide (TCN) geochronology to date offset landforms. Using these tools, we measure extension rates that are time-invariant, ranging from 0.1 ± 0.1 to 0.3 ± 0.1 mm/yr for fault dips of 30° and 60°. These rates are not high enough to account for the discrepancy between geologic and geodetic data in the ECSZ-Walker Lane transition zone. Based on geologic mapping and previously published geophysical data [Davis, 1981; Zampirro, 2005], deformation through Clayton Valley appears to be very widely-distributed. The diffuse nature of deformation leads to geologic slip rates that are underestimated due to the effects of off-fault deformation and unrecognized fault strands. Our results from Clayton Valley suggest that the discrepancy between geodetic and geologic strain rates at the latitude of the… Advisors/Committee Members: Frankel, Kurt (Committee Chair), Newman, Andrew (Committee Member), Peng, Zhigang (Committee Member).
Foy, Travis A. "Quaternary faulting in Clayton Valley, Nevada: implications for distributed deformation in the Eastern California shear zone-walker lane." 2011. Masters Thesis, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/39561.
Foy, Travis A. "Quaternary faulting in Clayton Valley, Nevada: implications for distributed deformation in the Eastern California shear zone-walker lane." 2011. Web. 23 Apr 2019.
Foy TA. Quaternary faulting in Clayton Valley, Nevada: implications for distributed deformation in the Eastern California shear zone-walker lane. [Internet] [Masters thesis]. Georgia Tech; 2011. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/39561.
13. Convers, Jaime Andres. Global investigations of radiated seismic energy and real-time implementation.
▼ This dissertation contains investigations of radiated seismic energy measurements from large earthquakes and duration determinations as significant properties of the dynamic earthquake rupture and its applications in the identification of very large and slow source rupturing earthquakes. This includes a description of earthquake released seismic energy from 1997 to 2010 and identification of slow source tsunami earthquakes in that time period. The implementation of these measurements in real-time since the beginning of 2009, with a case study of the Mentawai 2010 tsunami earthquake are also discussed. Further studies of rupture duration assessments and its technical improvements for more rapid and robust solutions are investigated as well, with application to the Tohoku-Oki 2011 earthquake an a case of directivity in the 2007 Mw 8.1 Solomon islands earthquake. Finally, the set of routines and programs developed for implementation at Georgia Tech and IRIS to produce the real-time results since 2009 presented in this study are described. Advisors/Committee Members: Newman, Andrew V. (advisor), Peng, Zhigang (committee member), Dufek, Josef (committee member), Fritz, Hermann (committee member).
Convers, Jaime Andres. "Global investigations of radiated seismic energy and real-time implementation." 2013. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/50356.
Convers, Jaime Andres. "Global investigations of radiated seismic energy and real-time implementation." 2013. Web. 23 Apr 2019.
Convers JA. Global investigations of radiated seismic energy and real-time implementation. [Internet] [Doctoral dissertation]. Georgia Tech; 2013. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/50356.
14. Craft, Kathleen L. Boundary layer models of hydrothermal circulation on Earth and Mars.
▼ Continental and submarine hydrothermal systems are commonly found around the world. Similar systems that sustain water or other fluids are also likely to exist in planetary bodies throughout the solar system. Also, terrestrial submarine systems have been suggested as the locations of the first life on Earth and may, therefore, provide indications of where to find life on other planetary bodies. The study of these systems is vital to the understanding of planetary heat transfer, chemical cycling, and biological processes; hence hydrothermal processes play a fundamental role in planetary evolution. In this thesis, three particular types of hydrothermal systems are investigated through the development of mathematical models: (1) terrestrial low-temperature diffuse flows at mid-oceanic ridges (MORs), (2) submarine near-axis convection on Earth, and (3) convection driven by magmatic intrusives on Mars. Model set-ups for all systems include a two-dimensional space with a vertical, hot wall, maintained at constant temperature, located adjacent to a water-saturated porous medium at a lower temperature. By assuming that convection occurs vigorously and within a thin layer next to the hot wall, boundary layer theory is applicable. The models provide steady-state, single-phase estimates of the total heat and mass transfer rates in each scenario over permeability ranges of 10-14 m2 to 10-10 m2 for the submarine systems and 10-14 m2 to 10-8 m2 for the Martian systems. Heat output results derived from the boundary layer model suggest that diffuse flow on MORs contributes 50% or less of heat output to the ridge system, which falls at the low end of observations. For the near-axis model, results found that heat transfer in the hydrothermal boundary layer was greater than the input from steady state generation of the oceanic crust by seafloor spreading. This suggests that the size of the mushy zone evolves with time. Heat output and fluid flux calculations for Martian systems show that fluid outflow adjacent to a single intrusion is too small to generate observed Martian surface features in a reasonable length of time. Advisors/Committee Members: Lowell, Robert (Committee Chair), Frankel, Kurt (Committee Member), Newman, Andrew (Committee Member).
Craft, Kathleen L. "Boundary layer models of hydrothermal circulation on Earth and Mars." 2008. Masters Thesis, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/26574.
Craft, Kathleen L. "Boundary layer models of hydrothermal circulation on Earth and Mars." 2008. Web. 23 Apr 2019.
Craft KL. Boundary layer models of hydrothermal circulation on Earth and Mars. [Internet] [Masters thesis]. Georgia Tech; 2008. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/26574.
15. Hopkins, Chelsea Elizabeth. Beryllium-10 derived erosion rates from the Hangay Mountains, Mongolia: landscape evolution in a periglacially-dominated continental interior.
▼ Terrestrial cosmogenic nuclides such as beryllium-10 have recently been used as a way to determine basin-average erosion rates around the world. These erosion rates are useful to geomorphologists investigating landscape evolution. The Hangay Mountains in Mongolia are a prime location to use beryllium-10 because of the granitic rocks that provide the quartz needed for cosmogenic analysis as well as the lack of observed evidence of recent or old mass wasting events that mobilize sediment and bedrock with much lower cosmogenic concentrations that cause underestimations of erosion rates. Basin-average erosion rates observed in seven basins across the eastern Hangay Mountains range from 12 m/My to about 20 m/My. These are of similar magnitude to those found in tectonically inactive regions such as the southern Appalachians. Comparing basin-average erosion rates to basin parameters, whole basin relief had the highest calculated R2 value and elevation had the lowest P-value. No strong relationships were seen between erosion rate and mean slope angle, hypsometric integral, area, or mean local relief. The basin-average erosion rates observed in the Hangay were compared to previous studies by Ahnert (1970), Portenga and Biernman (2011), and Matmon et al. (2009). We found erosion rates from the Hangay to be much lower than expected in our analyses. The differences in erosion rates from the Hangay Mountains compared to other places around the world are likely due to the fact that the streams in the Hangay are eroding into alluvium as opposed to bedrock, and are located in a landscape dominanted by diffusive hillslope sediment transport mechanisms. The erosion rate is limited to the amount of sediment that can be transported by the streams. Advisors/Committee Members: Frankel, Kurt (Committee Chair), Dufek, Josef (Committee Member), Newman, Andrew (Committee Member), Wegmann, Karl (Committee Member).
Hopkins, Chelsea Elizabeth. "Beryllium-10 derived erosion rates from the Hangay Mountains, Mongolia: landscape evolution in a periglacially-dominated continental interior." 2012. Masters Thesis, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/45799.
Hopkins, Chelsea Elizabeth. "Beryllium-10 derived erosion rates from the Hangay Mountains, Mongolia: landscape evolution in a periglacially-dominated continental interior." 2012. Web. 23 Apr 2019.
Hopkins CE. Beryllium-10 derived erosion rates from the Hangay Mountains, Mongolia: landscape evolution in a periglacially-dominated continental interior. [Internet] [Masters thesis]. Georgia Tech; 2012. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/45799.
16. Sullivan, Brendan. Delayed triggering of early aftershocks by multiple surface waves circling the earth.
▼ It is well known that direct surface waves of large earthquakes are capable of triggering shallow earthquakes and deep tremor at long-range distances. Recent studies have shown that multiple surface waves circling the earth could also remotely trigger microearthquakes. However, it is still not clear whether multiple surface waves returning back to the main shock epicenters could also trigger/modulate aftershock behavior. Here we conduct a study to search for evidence of such triggering by systematically examining aftershock patterns of earthquakes with magnitude ≥ 8 since 1990 that produce observable surface waves circling the globe repeatedly. We specifically examine the 2011 M9 Tohoku-Oki event using a composite catalog of JMA, HiNet and newly detected events obtained by waveform cross correlation. We compute the magnitude of completeness for each sequence, and stack all the sequences together to compute the seismicity and moment rates by sliding data windows. The sequences are also shuffled randomly and these rates are compared to the actual data as well as synthetic aftershock sequences to estimate the statistical significance of the results. Our results suggest that there is some moderate increase of early aftershock activity after a few hours when the surface waves return to the epicentral region. However, we could not completely rule out the possibility that such an increase is purely due to random fluctuations of aftershocks or caused by missing aftershocks in the first few hours after the mainshock. Advisors/Committee Members: Peng, Zhigang (Committee Chair), Huber, Christian (Committee Member), Newman, Andrew V. (Committee Member).
Sullivan, Brendan. "Delayed triggering of early aftershocks by multiple surface waves circling the earth." 2012. Masters Thesis, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/45827.
Sullivan, Brendan. "Delayed triggering of early aftershocks by multiple surface waves circling the earth." 2012. Web. 23 Apr 2019.
Sullivan B. Delayed triggering of early aftershocks by multiple surface waves circling the earth. [Internet] [Masters thesis]. Georgia Tech; 2012. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/45827.
17. Luo, Yan. Spatial and temporal variations of earthquake frequency-magnitude distribution at the subduction zone near the Nicoya Peninsula, Costa Rica.
▼ The Nicoya Peninsula of Costa Rica is unusually close to the Middle America Trench (MAT), such that interface locking along the megathrust is observable under land. Here, rapid convergence between the downgoing Cocos and the over-riding Caribbean plates at ~85mm/yr allows for observable high strain rates, frequent large earthquakes and ongoing micro-seismicity. By taking advantage of this ideal location, a network of 20 on-land broadband seismometers was established in cooperation between UC Santa Cruz, Georgia Tech, and OVSICORI, with most stations operating since 2008. To evaluate what seismicity tells us about the ongoing state of coupling along the interface, we must consistently evaluate the location and magnitude of ongoing micro- seismicity. Because of large levels of anthropogenic, biologic, and coastal noise, automatic detection of earthquakes remains problematic in this region. Thus, we resorted to detailed manual investigation of earthquake phases. So far, we have detected nearly 7,000 earthquakes below or near Nicoya between February and August 2009. From these events we evaluate the fine-scale frequency-magnitude distribution (FMD) along the subduction megathrust. The results from this b-value mapping" are compared with an earlier study of the seismicity 9 years prior. In addition, we evaluate them relative to the latest geodetically derived locking. Preliminary comparisons of spatial and temporal variations of the b-values will be reported here. Because ongoing manual detection of earthquakes is extremely laborious and some events might be easily neglected, we are implementing a match-filter detection algorithm to search for new events from the continuous seismic data. This new approach has been previously successful in identifying aftershocks of the 2004 Parkfield earthquake. To do so, we use the waveforms of 858 analyst-detected events as templates to search for similarly repeating events during the same periods that have been manually detected. Preliminary results on the effectiveness of this technique are reported. The overall goal of this research is to evaluate the evolution of stress along the megathrust that may indicate the location and magnitude of potentially large future earthquakes. To do so, I make the comparison between the FMD and the interface locking. Only positive correlations are observed in the Nicoya region. The result is different from the one derived from the seismic data set that was recorded 9 years before our data. Therefore, to substantiate the causes for the different relationships between the b-value and the coupling degree, we need additional data with more reliable magnitudes. Advisors/Committee Members: Newman, Andrew (Committee Chair), Dufek, Josef (Committee Member), Peng, Zhigang (Committee Member).
Luo, Yan. "Spatial and temporal variations of earthquake frequency-magnitude distribution at the subduction zone near the Nicoya Peninsula, Costa Rica." 2011. Masters Thesis, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/45963.
Luo, Yan. "Spatial and temporal variations of earthquake frequency-magnitude distribution at the subduction zone near the Nicoya Peninsula, Costa Rica." 2011. Web. 23 Apr 2019.
Luo Y. Spatial and temporal variations of earthquake frequency-magnitude distribution at the subduction zone near the Nicoya Peninsula, Costa Rica. [Internet] [Masters thesis]. Georgia Tech; 2011. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/45963.
18. Karakas, Ozge. Modulation of crustal magmatic systems by external tectonic forcing.
▼ We develop a two dimensional model that simulates the response of the crust to prolonged mantle-derived intrusions in arc environments. The domain includes the entire crustal section and upper mantle and focuses on the evolving thermal structure due to intrusions and external tectonic forcing. We monitor the thermal response, melt fraction and volume for different environments after a definite time by considering geologically relevant melt flux and extensional tectonic rates. The amount of crustal melt versus fractionated primary mantle melts present in the crustal column helps determine crustal structure and growth through time. We observe that with a geophysically estimated flux and tectonic rate, the mantle-derived magma bodies can melt the surrounding volume of crust. We express the amount of crustal melting in terms of an efficiency; therefore we define the melting efficiency as the ratio of the melted volume of crustal material to the volume of melt expected from a strict enthalpy balance as explained by Dufek and Bergantz (2005). Melting efficiencies are less than 1.0 in real systems because heat diffuses to sections of the crust that never melt. The maximum calculated efficiency is 0.05 in our model while most of our simulations show zero efficiency. Additionally, maximum total melt amount is observed in relatively greater extensional environments (0.02 m/yr) and high intrusion rates (10⁻² m³/m²/yr) and in long time periods (2 x 10⁶ years). However, maximum crustal melting in the same environment is reached in 1.2 x 10⁶ years. The relative amounts of mantle-derived and crustal melts in the total volume of magma suggest that the majority of magma composition in crustal column is derived from the mantle material. Advisors/Committee Members: Dufek, Josef (Committee Chair), Newman, Andrew (Committee Member), Peng, Zhigang (Committee Member).
Karakas, Ozge. "Modulation of crustal magmatic systems by external tectonic forcing." 2011. Masters Thesis, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/45964.
Karakas, Ozge. "Modulation of crustal magmatic systems by external tectonic forcing." 2011. Web. 23 Apr 2019.
Karakas O. Modulation of crustal magmatic systems by external tectonic forcing. [Internet] [Masters thesis]. Georgia Tech; 2011. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/45964.
19. Estep, Joseph Jeremiah. Analog and numerical experiments investigating force chain influences on the bed physics of dense granular flows.
▼ Granular materials are composed of solid, discrete particles and exhibit mechanical properties that range from fluid to solid behavior. Some of the complexity exhibited by granular systems arises due to the long-range order that develops due to particle-particle contact. Inter-particle forces in granular materials often form a distributive network of filamentary force-accommodating chains (i.e. force chains), such that a fraction of the total number of particles accommodates the majority of the forces in the system. The force chain network inherent to a system composed of granular materials controls the macroscopic behavior of the granular material. Force transmission by these filamentary chains is focused (or localized) to the grain scale at boundaries such as the granular flow substrate. Recent laboratory experiments have shown that force chains transmit extreme localized forces to the substrates of free surface granular flows. In this work we combine analog and numeric experimental approaches to investigate the forces at the bed of a simplified granular flow. A photoelastic experimental approach is used to resolve discrete forces in the granular flows. We also conduct discrete element method (DEM) simulations, using input parameters derived from measureable physical material properties of experimental and natural materials, which successfully reproduce the analog experimental results. This work suggests that force chain activity may play an unexpected and important role in the bed physics of dense granular flows through substrate modification by erosion and entrainment, and that DEM numerical methods effectively treat force chain processes in simulated granular flows. Advisors/Committee Members: Dufek, Josef (advisor), Newman, Andrew (committee member), Huber, Chris (committee member), Peng, Zhigang (committee member), Fritz, Hermann (committee member).
Estep, Joseph Jeremiah. "Analog and numerical experiments investigating force chain influences on the bed physics of dense granular flows." 2014. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/51768.
Estep, Joseph Jeremiah. "Analog and numerical experiments investigating force chain influences on the bed physics of dense granular flows." 2014. Web. 23 Apr 2019.
Estep JJ. Analog and numerical experiments investigating force chain influences on the bed physics of dense granular flows. [Internet] [Doctoral dissertation]. Georgia Tech; 2014. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/51768.
20. Mendez, Joshua. Granular electrification on earth and other worlds.
▼ When mobilized, granular materials, both natural and man-made, become electrified through a variety of processes. The phenomena resulting from such charging can be dramatic, as in the case of volcanic lightning, or quite subtle, like when fine ash particles clump together as they fall through the atmosphere. Despite being recognized in a plethora of natural systems, the microphysical processes underlying the electrostatic charging of granular materials still require clarification. In the present work, we experimentally explore electrostatic processes in both terrestrial systems and those on other worlds in our Solar System and beyond. On Earth, we focus on processes occurring in volcanic plumes, some of the most energetic granular flows on the planet. The motivation for this work is to aid in the development of novel tools that use signals from both lightning and slow-tarrying electric fields to monitor and probe the interior of volcanic plumes remotely. The work involving extraterrestrial systems, namely Saturn's moon Titan and the extra-solar world GJ1214b, explores how charging influences the dynamics of non-silicate granular flows and discharge processes in clouds of exotic materials. As a whole, this work demonstrates the diversity of electrostatic phenomena in granular flows and highlights the need for further research to elucidate their fundamental physical frameworks. Advisors/Committee Members: Dufek, Josef (advisor), Steffes, Paul (committee member), Newman, Andrew (committee member), Peng, Zhigang (committee member), Ferrier, Ken (committee member).
Mendez, Joshua. "Granular electrification on earth and other worlds." 2017. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/58760.
Mendez, Joshua. "Granular electrification on earth and other worlds." 2017. Web. 23 Apr 2019.
Mendez J. Granular electrification on earth and other worlds. [Internet] [Doctoral dissertation]. Georgia Tech; 2017. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/58760.
21. Zhao, Peng. Seismic velocity contrasts and temporal changes of strike-slip faults in central California.
▼ The spatial patterns of bimaterial interfaces along the Parkfield section of the San Andreas Fault (SAF) and central section of the Calaveras Fault are systematically investigated with large data sets of near-fault waveforms. Different from the usage of direct P and S waves in traditional tomographic studies, a particular seismic phase named fault zone head wave (FZHW) is used to image the bimaterial fault interfaces. The results show clear variations of seismic velocities contrast both along-strike and along-depth directions in both regions, which is in general consistent with local geological setting at surface and existing 3D tomography results. In the Parkfield section of SAF, the result of velocity contrast is used to test the relationship between preferred rupture directions of M6 Parkfield earthquakes and bimaterial interface. Strong velocity contrast (~5-10%) near Middle Mountain (MM) could control the rupture directions of nearby earthquakes to SE, such as the case for 1966 M6 Parkfield earthquake. In comparison, weak velocity contrast (~0-2%) near the epicenter of the 2004 Parkfield M6 earthquake (i.e., Gold Hill) probably has no influence on controlling its rupture direction, which is consistent with the bilateral rupture of the 2004 Parkfield earthquake. In the central Calaveras Fault, a detailed analysis of the moveout between FZHWs and direct P waves revealed the existence of a complicated fault structure with velocity contrast increasing from NW to SE of station CCO. The high velocity contrast SE of station CCO could be caused by a low-velocity zone SE of station CCO. The spatio-temporal variations of seismic velocity around the central Calaveras Fault and its nearby region are investigated based on the waveform analysis of 333 repeating clusters following the 1984 ML6.2 Morgan Hill earthquake. Clear reduction of seismic velocity is shown for all repeating clusters immediately after the mainshock, followed by a logarithmic recovery. The coseismic change mostly occurs at shallow layers (top few hundred meters) for the region away from the rupture area of the mainshock, but extends much deeper around the rupture zone of the Morgan Hill earthquake. The estimated depth of the damage zone is up to 6 km in the fault based on the repeating clusters directly beneath station CCO. Finally, temporal changes around the Parkfield section of SAF are studied using recently developed ambient noise cross-correlation technique. The extracted daily empirical Green functions (EGFs) from 0.4-1.3 Hz noise records are used to estimate subtle temporal changes associated with large earthquakes from local to teleseismic distances. The results show clear coseismic reduction of seismic velocities after the 2004 M6 Parkfield earthquake, similar to the previous observation based on repeating earthquakes. However, no systematic changes have been detected for other four regional/teleseismic events that have triggered clear tremor activity in the same region. These results suggest that temporal changes associated with distance… Advisors/Committee Members: Peng, Zhigang (Committee Chair), Assimaki, Dominic (Committee Member), Dufek, Josef (Committee Member), Newman, Andrew (Committee Member), Sabra, Karim (Committee Member).
Zhao, Peng. "Seismic velocity contrasts and temporal changes of strike-slip faults in central California." 2010. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/37242.
Zhao, Peng. "Seismic velocity contrasts and temporal changes of strike-slip faults in central California." 2010. Web. 23 Apr 2019.
Zhao P. Seismic velocity contrasts and temporal changes of strike-slip faults in central California. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/37242.
22. Wu, Chunquan. Fault zone damage, nonlinear site response, and dynamic triggering associated with seismic waves.
▼ My dissertation focuses primarily on the following three aspects associated with passing seismic waves in the field of earthquake seismology: temporal changes of fault zone properties, nonlinear site response, and dynamic triggering. Quantifying the temporal changes of material properties within and around active fault zones (FZ) is important for better understanding of rock rheology and estimating the strong ground motion that can be generated by large earthquakes. As high-amplitude seismic waves propagate through damaged FZ rocks and/or shallow surface layers, they may produce additional damage leading to nonlinear wave propagation effects and temporal changes of material properties (e.g., seismic velocity, attenuation). Previous studies have found several types of temporal changes in material properties with time scales of tens of seconds to several years. Here I systematically analyze temporal changes of fault zone (FZ) site response along the Karadere-Düzce branch of the North Anatolian fault that ruptured during the 1999 İzmit and Düzce earthquake sequences. The coseismic changes are on the order of 20-40%, and are followed by a logarithmic recovery over an apparent time scale of ~1 day. These results provide a bridge between the large-amplitude near-instantaneous changes and the lower-amplitude longer-duration variations observed in previous studies. The temporal changes measured from this high-resolution spectral ratio analysis also provide a refinement for the beginning of the longer more gradual process typically observed by analyzing repeating earthquakes. An improved knowledge on nonlinear site response is critical for better understanding strong ground motions and predicting shaking induced damages. I use the same sliding-window spectral ratio technique to analyze temporal changes in site response associated with the strong ground motion of the Mw6.6 2004 Mid-Niigata earthquake sequence recorded by the borehole stations in Japanese Digital Strong-Motion Seismograph Network (KiK-Net). The coseismic peak frequency drop, peak spectral ratio drop, and the postseismic recovery time roughly scale with the input ground motions when the peak ground velocity (PGV) is larger than ~5 cm/s, or the peak ground acceleration (PGA) is larger than ~100 Gal. The results suggest that at a given site the input ground motion plays an important role in controlling both the coseismic change and postseismic recovery in site response. In a follow-up study, I apply the same sliding-window spectral ratio technique to surface and borehole strong motion records at 6 KiK-Net sites, and stack results associated with different earthquakes that produce similar PGAs. In some cases I observe a weak coseismic drop in the peak frequency when the PGA is as small as ~20-30 Gal, and near instantaneous recovery after the passage of the direct S waves. The percentage of drop in the peak frequency starts to increase with increasing PGA values. A coseismic drop in the peak spectral ratio is also observed at 2 sites. When the PGA is larger than… Advisors/Committee Members: Peng, Zhigang (Committee Chair), Assimaki, Dominic (Committee Member), Dufek, Josef (Committee Member), Newman, Andrew (Committee Member), Sabra, Karim (Committee Member).
Wu, Chunquan. "Fault zone damage, nonlinear site response, and dynamic triggering associated with seismic waves." 2011. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/41143.
Wu, Chunquan. "Fault zone damage, nonlinear site response, and dynamic triggering associated with seismic waves." 2011. Web. 23 Apr 2019.
Wu C. Fault zone damage, nonlinear site response, and dynamic triggering associated with seismic waves. [Internet] [Doctoral dissertation]. Georgia Tech; 2011. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/41143.
23. Chao, Kevin Tzu-Kai. Global search of triggered non-volcanic tremor.
▼ Deep non-volcanic tremor is a newly discovered seismic phenomenon with low amplitude, long duration, and no clear P- and S-waves as compared with regular earthquake. Tremor has been observed at many major plate-boundary faults, providing new information about fault slip behaviors below the seismogenic zone. While tremor mostly occurs spontaneously (ambient tremor) or during episodic slow- slip events (SSEs), sometimes tremor can also be triggered during teleseismic waves of distance earthquakes, which is known as "triggered tremor". The primary focus of my Ph.D. work is to understand the physical mechanisms and necessary conditions of triggered tremor by systematic investigations in different tectonic regions. These include Taiwan, California, southwest Japan, Alaska and the Aleutian Arc, Cascadia, and New Zealand. In the first chapter of my dissertation, I conduct a systematic survey of triggered tremor beneath the Central Range (CR) in Taiwan for 45 teleseismic earthquakes from 1998 to 2009 with Mw ≥ 7.5. Triggered tremors are visually identified as bursts of high-frequency (2-8 Hz), non-impulsive, and long-duration seismic energy that are coherent among many seismic stations and modulated by the teleseismic surface waves. A total of 9 teleseismic earthquakes has triggered clear tremor in Taiwan. The peak ground velocity (PGV) of teleseismic surface waves is the most important factor in determining tremor triggering potential, with an apparent threshold of ~0.1 cm/s, or 7-8 kPa. However, such threshold is partially controlled by the background noise level, preventing triggered tremor with weaker amplitude from being observed. In addition, I find a positive correlation between the PGV and the triggered tremor amplitude, which is consistent with the prediction of the 'clock-advance' model. This suggests that triggered tremor can be considered as a sped-up occurrence of ambient tremor under fast loading from the passing surface waves. Finally, the incident angles of surface waves also play an important rule in controlling the tremor triggering potential. The next chapter focuses on a systematic comparison of triggered tremor around the Calaveras Fault (CF) in northern California (NC), the Parkfield-Cholame section of the San Andreas Fault (SAF) in central California (CC), and the San Jacinto Fault (SJF) in southern California (SC). Out of 42 large (Mw ≥7.5) earthquakes between 2001 and 2010, only the 2002 Mw 7.9 Denali fault earthquake triggered clear tremor in NC and SC. In comparison, abundant triggered and ambient tremor has been observed in CC. Further analysis reveal that the lack of triggered tremor observations in SC and NC is not simply a consequence of their different background noise levels as compared to CC, but rather reflects different background tremor rates in these regions. In the final chapter, I systematically search for triggered tremor following the 2011 Mw9.0 Tohoku-Oki earthquake in the regions where ambient or triggered tremor has been found before. The main purpose is to check whether… Advisors/Committee Members: Peng, Zhigang (Committee Chair), Dufek, Josef (Committee Member), Germanovich, Leonid (Committee Member), Huber, Christian (Committee Member), Newman, Andrew (Committee Member).
Chao, Kevin Tzu-Kai. "Global search of triggered non-volcanic tremor." 2012. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/44779.
Chao, Kevin Tzu-Kai. "Global search of triggered non-volcanic tremor." 2012. Web. 23 Apr 2019.
Chao KT. Global search of triggered non-volcanic tremor. [Internet] [Doctoral dissertation]. Georgia Tech; 2012. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/44779.
24. Su, Yanqing. Numerical study of the dynamic processes in volcanic eruptions: Bubble dynamics and volatiles diffusion.
▼ Volcanic eruption releases gases and aerosols (e.g., sulfur compounds) to the atmosphere, impacting climate for up to several years. While most research efforts of volcanologists to date have been devoted to unraveling the eruptive activity and formation of volcanoes, the understanding of volatiles diffusion during volcanic eruption is still preliminary, largely due to the lack of robust computational tools for magma dynamics during volcanic eruption at the necessary time and length scales. On the other hand, magmatic processes, from the production of melts in the upper mantle to their crystallization or eruption at the surface, are dominated by dynamic processes in deep Earth that are not directly observable, limiting the direct measurement of these processes through geological fieldwork. This dissertation includes three main parts: (i) a non-equilibrium bubble growth models are developed to assess the role of bubble dynamics and volatile kinetics in "excess sulfur" problem (Chap. 2) and the implication of the volatile diffusion profile after eruptions on magma ascent history (Chap. 3); (ii) a new bubble dynamics model that accounts for hydrodynamical interactions (deformation, coalescence) between bubbles are established (Chap. 4); (iii) the dynamical response of saturated porous media to transient stresses is studied using the lattice Boltzmann method with four different porous media topologies (Chap. 5). It is anticipated that the findings in this dissertation will improve physical understanding of volatile degassing, bubble dynamics, and saturated porous media in response to transient changes of stresses. Advisors/Committee Members: Huber, Christian (advisor), Dufek, Josef (committee member), Newman, Andrew (committee member), Peng, Zhigang (committee member), Wang, Jingfeng (committee member).
Su, Yanqing. "Numerical study of the dynamic processes in volcanic eruptions: Bubble dynamics and volatiles diffusion." 2017. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/58134.
Su, Yanqing. "Numerical study of the dynamic processes in volcanic eruptions: Bubble dynamics and volatiles diffusion." 2017. Web. 23 Apr 2019.
Su Y. Numerical study of the dynamic processes in volcanic eruptions: Bubble dynamics and volatiles diffusion. [Internet] [Doctoral dissertation]. Georgia Tech; 2017. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/58134.
25. Karakas, Ozge. Time and length scales of crust-magma interaction in rift settings.
▼ Understanding the processes that lead to magma emplacement and differentiation in the crust is of fundamental importance to science and society, as these magma bodies are important components of crustal growth and erupted products. During magma emplacement and residence in the Earth's crust, magma thermally and chemically evolves as a function of several complex nonlinear magmatic processes. This thesis work focuses on rift settings and quantifying the time and length scales involved in the thermal and compositional evolution of crustal magmas. In order to give quantitative constraints, this research utilizes a novel thermal-petrographic numerical model that solves for conservation of mass and energy in response to magma emplacement and extensional tectonic forces. In particular, this work tests the sensitivity of tectonic extension rates on crustal magma evolution. General trends of magma evolution are characterized in various rift systems. In particular, the numerical model is applied to Salton Sea Geothermal Field as a natural setting. This work delivers detailed insights to the interaction of magma and crust in extensional tectonic settings. The outcomes address important topics in volcanology including the timescales of generation of evolved magmas, and the thermal and compositional conditions that lead to the compositional diversity observed in diverse settings. Advisors/Committee Members: Dufek, Josef D. (committee member), Newman, Andrew V. (committee member), Huber, Christian (committee member), Peng, Zhigang (committee member), Mangan, Margaret T. (committee member).
Karakas, Ozge. "Time and length scales of crust-magma interaction in rift settings." 2015. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/55543.
Karakas, Ozge. "Time and length scales of crust-magma interaction in rift settings." 2015. Web. 23 Apr 2019.
Karakas O. Time and length scales of crust-magma interaction in rift settings. [Internet] [Doctoral dissertation]. Georgia Tech; 2015. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/55543.
26. Lifton, Zachery Meyer. Understanding an evolving diffuse plate boundary with geodesy and geochronology.
▼ Understanding spatial and temporal variations in strain accumulation and release along plate boundaries is a fundamental problem in tectonics. Short-term and long-term slip rates are expected to be equal if the regional stress field remains unchanged over time, yet discrepancies between modern geodetic (decadal time scale) slip rates and long-term geologic (103 to 106 years) slip rates have been observed on parts of the Pacific-North American plate boundary system. Contemporary geodetic slip rates are observed to be ~2 times greater than late Pleistocene geologic slip rates across the southern Walker Lane. I use a combination of GPS geodesy, detailed field geologic mapping, high-resolution LiDAR geodetic imaging, and terrestrial cosmogenic nuclide geochronology to investigate the observed discrepancy between long- and short-term slip rates. I find that the present day slip rate derived from GPS geodesy across the Walker Lane at ~37.5°N is 10.6 ± 0.5 mm/yr. GPS data suggest that much of the observed discrepancy occurs west of the White Mountains fault zone. New dextral slip rates on the White Mountains fault zone of 1.1 ± 0.1 mm/yr since 755 ka, 1.9 +0.5/-0.4 mm/yr since 75-115 ka, 1.9 +0.5/-0.4 mm/yr since 38.4 ± 9.0 ka, and 1.8 +2.8/-0.7 mm/yr since 6.2 ± 3.8 ka are significantly faster than previous estimates and suggest that slip rates there have remained constant since the middle Pleistocene. On the Lone Mountain fault I calculate slip rates of 0.8 ± 0.1 mm/yr since 14.6 ± 1.0 ka and 0.7 ± 0.1 mm/yr since 8.0 ± 0.5 ka, which suggest that extension in the Silver Peak-Lone Mountain extensional complex has increased dramatically since the late Pleistocene. Advisors/Committee Members: Newman, Andrew V. (advisor), Peng, Zhigang (committee member), Dufek, Josef (committee member), Lee, Jeffrey (committee member), Dixon, Timothy H. (committee member).
Lifton, Zachery Meyer. "Understanding an evolving diffuse plate boundary with geodesy and geochronology." 2013. Doctoral Dissertation, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/50316.
Lifton, Zachery Meyer. "Understanding an evolving diffuse plate boundary with geodesy and geochronology." 2013. Web. 23 Apr 2019.
Lifton ZM. Understanding an evolving diffuse plate boundary with geodesy and geochronology. [Internet] [Doctoral dissertation]. Georgia Tech; 2013. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/50316.
27. Liu, Lei. The link between convection and crystallization in a sub-axial magma chamber and heat output in a seafloor hydrothermal system.
▼ In this thesis, I present a simple time-dependent model of heat transfer between a turbulently convecting and crystallizing magma body and the overlying hydrothermal circulation. Most of the known seafloor hydrothermal sites on faster-spreading ridges are dominated by basalt. The hydrothermal fields within parts of the Lau Basin in the Southwest Pacific are driven by andesitic magma. To determinate the different characteristics of magma-driven hydrothermal system, two types of magma material, basaltic and andesitic magma are considered. Two different crystallization scenarios are considered¡ªcrystals in suspension and crystals settling. In either case, I assume that large-scale convection within the magma chamber is homogenous. Also, the effect of crystallinity and water content-dependent magmatic viscosity is considered. Based on the proposed models, the total heat output from the upper surface of the magma chamber and the temperature in hydrothermal system are derived numerically. The simulation results show that without magma replenishment, the heat output and hydrothermal temperature decay rapidly within about ten years. For two different crystallization distribution cases, such rapid decay is not consistent with observations. The conflict between the simulation results and the field observations shows the need to develop more accurate magma convection models. Different from the existing modeling methods, I propose to model the magma convection with replenishment. The replenishment model can be classified into two categories in terms of status of magma chamber size. To replenish the magma system without changing the magma chamber size, the heat flux decaying rate is slowed down and hydrothermal system lifetime is extended for a little longer. Although this model is more accurate than existing ones in terms of slow decaying rate of heat flux, it does not achieve a steady state as is observed. This leads us to model replenishment with variant magma chamber size. I model the replenishment rate as a constant and exponential decay, respectively. Thus, I assume the magma chamber size is time-varying. Simulation results show that magma heat flux approaches a steady state over a time scale of decades. This result is consistent with the observations, which indicates the effectiveness of proposed modeling methods. Advisors/Committee Members: Lowell, Robert (Committee Chair), Germanovich, Leonid (Committee Member), Newman, Andrew (Committee Member).
Liu, Lei. "The link between convection and crystallization in a sub-axial magma chamber and heat output in a seafloor hydrothermal system." 2007. Masters Thesis, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/16312.
Liu, Lei. "The link between convection and crystallization in a sub-axial magma chamber and heat output in a seafloor hydrothermal system." 2007. Web. 23 Apr 2019.
Liu L. The link between convection and crystallization in a sub-axial magma chamber and heat output in a seafloor hydrothermal system. [Internet] [Masters thesis]. Georgia Tech; 2007. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/16312.
28. Gosnell, Sawyer Ross. Numerical modeling of induced diffuse flow in seafloor hydrothermal systems.
▼ Examining the processes that control diffuse flow in seafloor hydrothermal systems can provide insight into what is happening below the seafloor at mid-ocean ridges. The diffuse flow could be either entrained seafloor fluids mixed with hot, upwelling fluids, or diffuse flow could be driven by sidewall heating across some low permeability barrier. This barrier would separate the diffuse flow fluids from the high temperature fluids, effectively preventing mixing. Three parameters were manipulated through a numerical model based on the single-pass model, and the fluid and heat flow results analyzed and compared to observed hydrothermal systems. These three parameters are depth of the extrusive layer at the top of the system, the permeability of the extrusive layer, and the existence of a low permeability barrier separating the high-temperature output from the induced diffuse flow. Advisors/Committee Members: Lowell, Robert (Committee Chair), Long, Tim (Committee Member), Newman, Andrew (Committee Member).
Gosnell, Sawyer Ross. "Numerical modeling of induced diffuse flow in seafloor hydrothermal systems." 2006. Masters Thesis, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/13932.
Gosnell, Sawyer Ross. "Numerical modeling of induced diffuse flow in seafloor hydrothermal systems." 2006. Web. 23 Apr 2019.
Gosnell SR. Numerical modeling of induced diffuse flow in seafloor hydrothermal systems. [Internet] [Masters thesis]. Georgia Tech; 2006. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/13932.
29. Crowell, Brendan William. Biological sulfur reactions and the influence on fluid flow at mid-ocean ridge hydrothermal systems.
▼ This thesis is an investigation into biogenic sulfide oxidation and sulfate reduction associated with hydrothermal systems at oceanic spreading centers. First, the production of sulfur floc and 'snowblower' events due to sulfide oxidizing bacteria is investigated. The effects of sulfur floc on the pososity is shown to be negligible. 'Snowblower' events are shown to be sulfur floc that is stored over long periods of time mixed with a component of sulfur floc being created in a bloom event. Secondly, biogenic sulfate reduction in hydrothermal recharge zones is investigated and the effects on the concentration profiles is considered. Advisors/Committee Members: Lowell, Robert (Committee Chair), Newman, Andrew (Committee Member), Peng, Zhigang (Committee Member).
Crowell, Brendan William. "Biological sulfur reactions and the influence on fluid flow at mid-ocean ridge hydrothermal systems." 2007. Masters Thesis, Georgia Tech. Accessed April 23, 2019. http://hdl.handle.net/1853/16234.
Crowell, Brendan William. "Biological sulfur reactions and the influence on fluid flow at mid-ocean ridge hydrothermal systems." 2007. Web. 23 Apr 2019.
Crowell BW. Biological sulfur reactions and the influence on fluid flow at mid-ocean ridge hydrothermal systems. [Internet] [Masters thesis]. Georgia Tech; 2007. [cited 2019 Apr 23]. Available from: http://hdl.handle.net/1853/16234.


Moringa oleifera belongs to the family of the Moringaceae. The plant is also known as horseradish tree, drumstick tree, moringa or ben oil tree. Some people even call it "The tree of life" or miracle tree. M. oleifera is native to the Himalaya region in India. Today it is cultivated all over the world because it has many different skills. But India is still the major producer of Moringa. M. oleifera is an evergreen, perennial tree. It grows very fast about 30 cm per month. One can really watch it grow. After just one year it has already reached a height of about 4 m. All in all it can reach a height of 12 m and the trunk gets 45 cm in diameter. In culture the miracle tree is often treated like an annual plant. It is quite astonishing that all parts of the plant can be used. The leaves of M. oleifera are tripinnate. The small leaves are 1 to 2 cm long and the whole pinnate leave gets 20 to 25 cm long.
The leaves contain the most nutrients. They can be cooked like spinach or boiled in a soup. To make them durable one can put them in a sour medium like cucumbers. They still taste very good after that treatment. The dried variation of the leaves is also still rich in nutrients. One can mix the dried leaves with flour to get bread that has more nutrients than normal. The leaves of the miracle tree contain 18 of the 20 amino acids. Some of those are essential what means that our body is not able to produce them. We have to get them from the food. Eating the leaves of Moringa oleifera our daily needs of amino acids are satisfied. Moreover the leaves include many vitamins like vitamin B, C and provitamin A. For example Moringa oleifera Moringa oleifera leaves includes twice more provitamin A as a carrot. Malnourishment can be avoided if one eats enough Moringa. Used as a dietary supplement the miracle tree has really an effect in contrast to many other dietary supplements that are mentioned in the advertisement. The leaves contain also many antioxidant substances. Antioxidant substances are able to eliminated free oxygen radicals that are produced in the human body. To have some free oxygen radicals in the body is totally normal, but stress and other poisons from the environment can increase those free oxygen radicals. The antioxidant substances in the leaves of Moringa oleifera are able to bind those free oxygen radicals. Doing so, they decrease the risk of getting cancer because less DNA is destroyed. The antioxidant potential of a substance is rated with the so called ORAC Value. The miracle tree reaches a value of 75000. This is a value that no plant except Moringa oleifera ever reached. The leaves are also used as food for animals by many farmers.
The fruits of the miracle are longish capsules. They can get 45 cm long and are about as long as the arm bed. The fruit looks like and drumstick, because of that the natives call Moringa oleifera also drumstick tree. One tree can have many fruits. That makes it very attractive for cultivation. The fruits can be eaten like normal vegetables. If they are cooked they taste a bit like asparagus. But they can be also eaten raw, cooking is not essential. In the white pulp of the fruits there are the seeds of Moringa oleifera. They are also called ben nuts. The seeds are small, brownish to blackish, round or triangular and have three wings. They reach 1 cm in diameter. The seeds of Moringa oleifera are Moringa oleifera poddistributed with the wind or with the water, because they are able to swim, too. They can be cooked and eaten or it is also possible to roast them like nuts. But the seeds of Moringa can do much more than just being food.
The seeds of Moringa are able to clean dirty water and make it drinkable again. For that the seeds have to be prepared. First of all one has to remove the wings. Then the seeds have to be crushed until there is only a powder left. This powder can be mixed into the dirty water. After 40 minutes the water is much clearer that before and drinkable again. Just 0,2g of the crushed Moringa seeds are needed to clean one liter of water. The principal behind this miracle is quite simple. Decontamination occurs because the Moringa seeds contain a protein that binds to the particles and bacteria in the water. Those aggregations can be removed from the water, because they are heavy and sink to the ground. The Moringa seeds also kill some bacteria. Studies showed that there is no growth in petri dishes when one adds a Moringa extract to the bacteria. In contrast there is a high growth when Moringa extract is missing. The cleaning of water with Moringa seeds functions better than some chemical alternatives and is much cheaper. In Africa or other poor countries where clean water is rarely found the miracle tree could really be a miracle for the people living there. They could get very easy clean water that does not cause them any illnesses. Many universities worldwide are working on projects to establish constructions in the poor countries that function. The seeds of Moringa oleifera can also be used to gain oil. 45% of the weight of the seeds is oil. The oil is nearly odorless and gets rarely rancid like other oils do. In the cosmetic it was used to eliminate bad odors. Already the old Greeks used the oil. It was also part of perfumes and is used for perfumes until today. After gaining the oil out of the seeds, the "rubbish" can be used to clean the water. So nothing has to be thrown away.
The flowers of Moringa oleifera are whitish. They have five flower leaves and reach 2 to 3 cm in diameter. They are clustered in inflorescences that are placed in the leaf axilla. The odor of the flowers is very pleasant. Some say it smells like honey or viola.Moringa flowers The miracle tree starts to flower 6 to 8 month after germination. The tree flowers the whole year when the conditions are good. This makes Moringa oleifera very interesting for beekeepers, because with the miracle tree they have the whole year food for their bees. But not just the bees can eat the flowers; the humans can do so, too. The flowers can be used for making tea. This shall help against cough or a cold. Alternatively they can be put into a soup. They taste a little like fungi.
Moringa oleifera is also used to produce wood. As mentioned before, M. oleifera grows very fast and though produces much wood. The wood is used by the natives as fire wood. The bark can be used to produce papers or ropes. The roots of the miracle tree are used mainly in medicine. They contain glycosides that give it a sharp taste. Due to that fact M. oleifera has been given the name horseradish tree. The rasped roots are used as spice. The root of the miracle tree is said to have an antibacterial effect. Due to that is it used against various inflammations and as an antibiotic. The crushed root shall help against rheumatism and arthralgia. The root is the only part of the tree that must be threatened with care. It includes also some alkaloids which are potential nerve paralyzing. All in all there is nearly nothing that the Moringa tree is not able to do and so it deserves it to be called miracle tree!
The seeds of Moringa oleifera should be put into warm water 24 h before planting. After that they can be planted 1 cm deep into the substrate. The substrate should be a mix of soil and sand. This substrate should be constantly moist at a temperature of about 23 to 25°C. The germination occurs really fast after about 10 to 14 days, sometimes even faster. The Moringa tree does not need much water when it is adult. It is very resistant against drought. Due to this fact it is easy to cultivate it in Africa, where rain is sometimes rare. Moringa oleifera likes sunny or semi shaded places. It is not winter hardy and should be put into the house over the cold season.
Our seeds are fresh and grown organically and can be used for plantation as well as a supplement !


text:
Despite an official call to the countrymen to stay at home and maintain social distancing during the lockdown, people at various places in the districts are not following any restrictive norms for containing coronavirus (COVID-19) spread.
The working class people in the districts said that they were compelled to come out of their homes as they had no food at home and they did not get any government assistance while the administration and the law enforcement agencies had been asking people to remain at home.
Reports received from Jashore, Lalmonirhat, Satkhira, Feni, Lakshmipur, Patuakhali, Cumilla, Manikganj and Kushtia said that the presence of people on the roads were thin as all the shops, barring grocer's and medicine, remained closed and government officials, political parties as well as different organisations and rich people had been distributing food items among the poor, though they were too little to meet the demand.
In Feni, the presence of people on roads had increased on Tuesday while buyers were seen buying goods from TCB's truck-sale at Trank Road without maintaining the rules of social distancing. Same was observed at Bara Bazaar and Rail Gate Bazaar.
People were seen gathering in front of tea stalls and small shops at different places of the district town.
In Satkhira, deputy commissioner SM Mostafa Kamal, accompanied by army personnel, was seen asking people to stay at home using public announcement system.
He said that the government was providing food for the working class people.
He later distributed food relief among over 50 destitute families.
In Patuakhali district town, construction worker Md Awal of Coast Guard Camp area, laundry shop worker Anil Dash of Shre-e-Bangla Road, and mechanic Robi at Sadar Road told New Age that they were jobless for the past six days and were now compelled to come out as they had no food in their homes. They said that they were yet to get any assistance from anyone.
Patuakhali DC Md Motiul Islam Chowdhury said that they were preparing a list to assist the government.
New Age correspondent in Jashore reported that district superintendent of police Muhammad Ashraf Hossain, Journalist Mir Moin Hossain Musa and Swechchashebak Dal separately distributed food items among the poor of the district.
In Lakshmipur, district administration officials said about 4,500 expatriates came back to the district in the past three weeks and most of them still remained untraced.
Besides, a huge number of people who work at jobs elsewhere in the country returned home, increasing the risk of coronavirus spread in the district.
Though the town as well as the markets at upazilas remained almost empty, gatherings at village tea stalls have increased, especially in the evening.
Schoolteacher Belayet Hossain said that farmers and agricultural workers were hit hard as their produces were not sold and even the milk price was halved. (Source: New Age)
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redpajama_set_name: RedPajamaCommonCrawl


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