Mass movement case studies
Mass movement case studies
Vaiont
| Location | Vaiont Reservoir North Italy |
| Date and time | 9th Oct 1963 |
| Effects | Created wave 100m high, caused dam to overflow - flooded valley and killed 2000 people |
| Trigger | Heavy rainfall, reactivating an old slide |
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Contributory factors jj
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·Rocks dip towards bottom of valley, creating slip planes |
| Mitigation | Manmade rather than natural - no mitigation |
Venezuela
| Location | Northern Venezuela, edge of Caracas, |
| Date and time | 15th 16th Dec 1999 |
| Effects ..................... | 30000 died, 400 000 homeless, shanty towns washed away on hillsides, plantations, roads destroyed, airport closed. Billions of dollars damage. |
| Trigger | Heavy rain. - 900mm fell 15th 16th - flash floods. |
| Contributory factors ................................. . | Soil saturated from earlier storms so shear strength weakened. Deforestation and building of shanty towns on steep slopes - less interception and soil not held together. Steep slopes Corruption of government had allowed housing on steep slopes. |
| Mitigation ............... . | No mitigation. Aid slow to reach people. Came from USA etc. Many physical factors here, but made more dangerous by development on shanty towns on unsuitable land. |
Cherry Hills Antipolo City
Location |
10km east of Manila, Philippines. |
| Date and time | 3rd Aug 1999 |
| Effects | Landslide, houses destroyed and 58 killed. |
| Trigger | Heavy rain 31st to 2nd August, owing to Cyclone Ising adding to monsoon |
| Contributory factors ................................. . | Low cost housing on slopes up to 25º Fractured sandstones, clays which vary in permeability Numerous landslides in the past Early signs ignored - in 1998 cracks were found |
| Mitigation | No mitigation. Poor planning - this is not a suitable site, but people have returned as there is nowhere else to go. |
Los Colinas El Salvador 2001
| Location | La Colinas El Salvador |
| Date and time | 13th Jan 2001 |
| Effects | Hundreds died, mudflow engulfed the settlement |
| Trigger | 7.6. earthquake in Pacific ocean |
| Contributory factors ................. . | Residential area at foot of steep slope. Environmental groups had protested against deforestation and over development. Law suit brought against construction company, but overturned in1999 |
| Mitigation | No mitigation. Will be built on again - though not likely to be middle class |
