EOSC 114 Lecture : Landslides Notes.docx
3 Aug 2013
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Lesson 1: why study landslides, socioeconomic impacts, the effects of gravity and factor of safety. Lesson 2: slope stability and volcanic activity. When volcanic ash is released on hillsides, there is an accelerated erosion and mud or debris flow triggered by intense rainfalls. Volcanic eruptions have triggered the largest landslides: slope stability and earthquakes. Strong shaking is a common triggering factor for landslides. Earthquakes m 4. 0 can trigger landslides in susceptible slopes, and larger earthquakes can generate many landslides. Small magnitude earthquakes less than 4. 0 can generate falls over less than 10km2 and earthquakes over magnitude 6. 0 can generate avalanches affecting areas over 3 magnitudes larger. Liquefaction can easily be generated by smaller earthquakes. Earthquake shaking destabilizes loose rock on steep slopes. Seismic slopes destabilize slopes by increasing shear stress as the internal structure of the slope material weakens: slope stability and anthropogenic activity.
