Found the following article online, use it to answer the question: What was the first name of the man who wrote a paper about the rockside-debris avalanche of May 18, 1980?

Most of Glicken's published work centers around the 1980 eruption of Mount St. Helens. He also coauthored works with other volcanologists that focused on debris avalanches. Colleague Jon Major writes that "The full scope of Harry's work ... has never been published."
"The 1980 eruptions of Mount St. Helens, Washington. USGS Professional Paper No. 1250". United States Geological Survey. 1981: pgs. 347–377.
Meyer, William; Sabol, M.A; Glicken, H.X; Voight, Barry (1981). "The effects of ground water, slope stability, and seismic hazards on the stability of the South Fork Castle Creek blockage in the Mount St. Helens area, Washington. USGS Professional Paper No. 1345". United States Geological Survey.
"The effects of ground water, slope stability, and seismic hazard on the stability of the South Fork Castle Creek blockage in the Mount St. Helens area, Washington. USGS Open File No. 84–624". United States Geological Survey. 1984.
Glicken, Harry X.; Meyer, William; Sabol, Martha A. (1989). "Geology and ground-water hydrology of Spirit Lake blockage, Mount St. Helens, Washington, with implications for lake retention. USGS Bulletin No. 1789". United States Geological Survey.
Glicken, Harry (1996). "Rockslide-debris avalanche of May 18, 1980, Mount St. Helens Volcano, Washington. USGS Open File No. 96-677". United States Geological Survey: 98.

Harry