The Geologic Effects of the Eruption (Sidebar 2)

A. Strata deposited 1. Up to 600 feet of strata were deposited 2. The strata were not homogenized as was expected, but had minute layering 3. Each layer seems to have taken only minutes to form B. Canyon erosion 1. Canyons were eroded through solid rock up to 100 feet deep 2. Loowit Canyon 3. Canyons were formed as a result of 500o F sediment covering glaciers. The glaciers melted and a steam pit collapsed. 4. Toutle River had been blocked by the landslide, but was unblocked in 1982 and new channels were cut a. 5 canyons, some over 100 ft. deep were cut b. A "miniature Grand Canyon" was cut in one day

Sequence of Strata Depositions