EARTH 20 Lecture Notes - Lecture 11: Debris Flow, 1994 Northridge Earthquake, Silt
Document Summary
Rapid downslope movement of earth materials (rock or soil) as a coherent mass . Catastrophic mass movements usually triggered by some other event, such as earthquake, volcanic eruption, major rainstorm . Weak glacial sediment possibly resting on dense layer of silt and clay. Past landslides on same slope in 1949,1951, 1967, 1988, and 2006. > million in property damage (not covered by insurance) > million on recovery & rescue operations. Effects of landslides and linkages with other natural hazards. In united states 25 people are killed each year. Disease ( valley fever ) spores kicked up by landslide during northridge earthquake. Earthquakes, volcanoes, storms, and fires landslides. Daylighting layers rock layers slanting diagonally downwards. Hospitals, schools, and police & fire stations. Limited development (between ocean and high cliff) High uplift rates along the red mountain fault. Potential for water to seep into cracks. Heavy rainfall leading up to landslide added to already elevated groundwater level.
