1.7C - Multiple Hazard Zones
The concept of a multiple-hazard zone, and how linked hydrometeorological hazards sometimes contribute to a tectonic disaster. (Philippines)
Multiple hazard zones are places where two or more natural hazards occur, and in some cases interact to produce complex disasters. Examples are California, Indonesia and Japan. These locations:
- are tectonically active and so earthquakes (and often eruptions) are common
- are geologically young with unstable mountain zones prone to landslides
- are often on major storm tracks either in the mid-latitudes or on tropical cyclone tracks
- may suffer from global climate perturbations such as El Niño and La Niña
Famously, during the 1991 eruption of Mount Pinatubo in the Philippines the area was struck by Typhoon Yunga. Heavy rainfall from the typhoon mobilised volcanic ash into destructive lahars. This shows how linked hydrometeorological hazards can contribute to tectonic disasters.
This eruption could have been significantly worse in terms of impact, but it was successfully predicted and evacuation limited the death toll to about 850. In many earthquake-prone areas, landslides can be triggered by heavy rain on slopes previously weakened by earthquake tremors.
A multiple hazard zone with complex hazards is a combination of tectonic hazards and hydro-meteorological hazards.
- Tectonic hazards: earthquakes, volcanic eruptions, tsunami, landslides
- Hydro-meteorological: flood, drought, storms, tropical cyclones