MOUNT RAINIER: The Volcano That Doesn’t Need Lava to Kill

Mount Rainier is the most glaciated peak in the contiguous United States and carries more ice than every other volcano in the Cascade Range combined. Its greatest threat is not lava, not ash, and not pyroclastic flow. It is the mountain's own rotting interior, mixed with a cubic mile of glacial water, sliding down on top of a metropolitan area of two and a half million people. The eruption is optional. The catastrophe is not. This documentary traces the geological mechanism of the Osceola Mudflow of approximately 5,600 years ago, the Electron Mudflow of 1507, the hydrothermal alteration that has been weakening the upper west flank for hundreds of thousands of years, and the modern arrival-time models that quantify what the next event will cost the cities downstream. CHAPTERS 00:00 Rainier's Deadliest Threat Is Not Lava 00:15 The Osceola Mudflow Reaches Puget Sound 01:49 Takhoma, Cities, and Forgotten Warnings 02:20 Why Rainier Is Not Mount St. Helens 03:49 Glaciers on a Heat Source 04:50 What a Lahar Really Is 06:53 The Mountain Rotting From Within 09:37 The Osceola Collapse Mechanism 11:35 The 1507 Electron Mudflow 14:07 Sirens, Drills, and Evacuation Routes 15:16 A Lahar Without an Eruption 18:11 The Warning System Can Only Detect Motion 19:14 USGS Simulations and Arrival Times 21:05 Hazard Maps, Zoning, and Unequal Risk 23:00 The 500-Year Clock and a Warming Mountain SOURCES Vallance, J. W., and Scott, K. M. (1997). The Osceola Mudflow from Mount Rainier: Sedimentology and hazard implications of a huge clay-rich debris flow. Geological Society of America Bulletin, 109(2), 143–163. DOI: 10.1130/0016-7606(1997)1090143:TOMFMR 2.3.CO;2 John, D. A., Sisson, T. W., Breit, G. N., Rye, R. O., and Vallance, J. W. (2008). Characteristics, extent and origin of hydrothermal alteration at Mount Rainier Volcano, Cascades Arc, USA: Implications for debris-flow hazards and mineral deposits. Journal of Volcanology and Geothermal Research, 175(3), 289–314. DOI: 10.1016/j.jvolgeores.2008.03.024 Iverson, R. M., Schilling, S. P., and Vallance, J. W. (1998). Objective delineation of lahar-inundation hazard zones. Geological Society of America Bulletin, 110(8), 972–984. DOI: 10.1130/0016-7606(1998)110 0972:ODOLIH 2.3.CO;2 Crandell, D. R. (1971). Postglacial lahars from Mount Rainier volcano, Washington. U.S. Geological Survey Professional Paper 677, 75 pages. Driedger, C. L., and Kennard, P. M. (1986). Glacier volumes on Cascade volcanoes — Mount Rainier, Mount Hood, Three Sisters, and Mount Shasta. U.S. Geological Survey Professional Paper 1365. Atwater, B. F., Musumi-Rokkaku, S., Satake, K., Tsuji, Y., Ueda, K., and Yamaguchi, D. K. (2005). The Orphan Tsunami of 1700: Japanese clues to a parent earthquake in North America. U.S. Geological Survey Professional Paper 1707.