STURZTROMS: Large Volume, High Velocity, Killer Debris Flows Friday March 8 10am Lecture ​and Saturday March 9 9am Field Trip ​In 1881, a rock quarry in Switzerland had a massive wall failure wherein 10 million cubic meters of rock fell 2,000 feet, shattered, and then flowed 110 mph for 1.4 miles into the town of Elm, destroying 2/3 of the people and their houses. The event was brilliantly described by Albert Heim who labeled the event as a sturzstrom. There are many counterintuitive features in this phenomenon. Split Mountain Gorge has world-class exposures of two huge sturzstrom deposits. One flowed along the ground in latest Miocene time, the second flowed along the sea floor in earliest Pliocene time. The two sturzstrom deposits look identical within their bodies, but there are marked differences in their bottoms and tops. We will talk about truly unique features on Friday that should leave you full of doubts. On Saturday, we will go to Split Mountain Gorge and do what geologists do best – look at the rocks and discuss their origin in the field. In 1996, Pat led a South Coast Geological Society field trip there with 275 geologists in attendance. All participants began with massive doubts, but they left with new perspectives.

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