|Imperial California Earthquake, October 1979|
Page: Aerials | Ground | Close-ups | Other Earthquakes
Imperial Fault trace 1 kilometer south of County Highway S-80
(11.3 kilometers northwest of the southeast end of the fault). Echelon fissures (vertically oriented)
trend N. 20-50 degrees W. The fault trace trends between N. 30-40 degrees W. Compressional features
(dark horizontal bands) join the ends of the separate echelon fractures. The distance between the
manmade berms (wide dark diagonal bands) is about 9.1 meters. The maximum width of the obviously
deformed zone is about 0.6 meter. View is south.
Arcuate incipient-slump scarp with 13 centimeters of vertical separation
in the embankment at site 33 east of River Park in Brawley. View is southeast.
State Highway 86 bridge over the New River at site 32 west of
Brawley. The abutment fill settled about 0.15
meter, and both ends of the bridge and riverbanks slumped about 0.1 meter toward the stream. Ground
displacements caused the bridge decks to rotate about 0.3 degree counterclockwise in a horizontal
plane, but did not seriously damage the structure.
Imperial Fault at Harris Road site 67, which passes between the
utility poles on the right. The sinuosity of the fault trace is typical of much of the northern
segment of the Imperial Fault where the vertical component of the slip is large. Gullying of
the upthrown (southwest) side of the fault has etched the rounded late Holocene scarp. Note the
general, but imperfect, congruence of the new surface rupture (dark narrow line) with the base
of the older escarpment. View is southwest.
Main branch of the Imperial Fault (29.2 kilometers northwest of the
southeast end of the fault), 0.4 to 0.8 kilometer north of Carey Road. The surface break is the
dark line at the base of the low, slightly gullied scarp in the foreground. The trace generally
follows the curved edge of the cultivated field in the distance and converges with the curved
concrete canal liner at the top. View is northeast.
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Credits: All earthquake photographs courtesy of the U.S. Geological Survey. YupRocks makes no copyright claims on these photographs; they are public domain and may be freely distributed.