University:
Capital University
Course:
GEOL 230 | Environmental Geology
Academic year:

2020
Views:

421

Pages:

2
Author:

Jameson Hunt

California Landslides Types of Landslides: • • • • • Falls Topples Slides Lateral Spreads Flows Yosemite National Park: • • • • Happy Isles Rock Fall, 1996 70,000 cubic yards fell 2,000 feet Damages caused by winding effect Dust spread for miles around the impact site La Conchita Landslides: • • • • • • • History o 1930s Survey: Lowest priced parcels built entirely on mud flow debris. o As far back as the 1800's there have been recorded histories of landslides o 1865 merchant account o 1899 Southern Pacific Railroad relocates tracks 1995 o Claimed $24 million in damages o 1.7 million cubic yards of earth slid more than 600 feet o 3 confirmed fatalities o Dramatic loss in property value 2005 Re-activation of landslide of 1995 Much more viscous flow 13 homes destroyed, 23 others deemed unlivable 10 confirmed fatalities San Francisco Bay Area • • • • • 1997-98 El Nino Winter caused 1,800 recorded landslide events President Clinton declared it an emergency deserving of FEMA. Some areas in the 10 county region experienced 240% of their annual rainfall Slides measured from 33 cubic yards to 17 million cubic yards 6,500 homes in disrepair, 1,000 businesses damaged and 33 people died Mitigation Efforts • • • • • Avoid building in seriously prone areas Build culvert streams to drain groundwater Build safety walls with anchors deep in slopes Place slide sensors in prone areas EDUCATE THE PUBLIC !!!