By Hyungbae Park (Tyler) ESS 315 Hebgen Lake Landslide By Hyungbae Park (Tyler) ESS 315

Overview Also, known as 1959 Yellowstone Earthquake 11:37 pm (MST) on August 17th, 1959 Southwestern Montana, United States Cause: Magnitude of 7.5 earthquake for about 40 seconds Strongest earthquake to hit Montana since 1935-36 Helena earthquake Worst landslides in the history of Northwestern U.S. since 1927 Damage: 28 deaths $11 million damage

Location

Characteristics Type: Rock, Trees, and Debris Avalanches Type of Soil: 15 ft Type: Rock, Trees, and Debris Avalanches Type of Soil: Schistose Bedrock Sedimentary layer (Dolomite) Thin layer of foliation Landslide created a lake as it slid into the valley Later named Quake Lake Quake Lake Quickly filled with water Growing Quake Lake swept homes and highways Fault Scarp Ripped through the camp grounds to the north of the Madison River The length of the scarp is about 12 miles Fault Scarp Campground 1959 Fault Scarp in campground 2004

Damages Highway 287 Madison River Landslide Highway 287 & 191 were mostly damaged causing huge cracks Many people used these roads for fleeing 28 deaths were caused due to Madison slide

Building collapse at the Blaneystone Ranch, near Hebgen Lake A fault scarp near Red Canyon Creek – 5.7 meter displacement from the earthquake White Ridge of dolomite boulders due to the Madison River landslide Disrupted trees, roads & swept house

Sources http://www.nature.nps.gov/geology/gip/web_products/YELL_2008_GIP_Grub bWheeler_hebgen.pdf http://gradyent.blogspot.com/2013/08/earthquake-or-how-quake-lake-was- formed.html http://www.earthmagazine.org/article/benchmarks-hebgen-lake-earthquake- and-landslide http://earthquake.usgs.gov/earthquakes/states/events/1959_08_18.php