Hazard profile - earthquakes (1)

Are earthquakes predictable?

No, they are very difficult to predict

Are there any warning signs for earthquakes?

No there are no warning signs, apart from small tremors sometimes

What theory can try to predict earthquakes?

Seismic gap theory

How frequent are large earthquake events?

Larger earthquake events are less frequent as it needs time for energy to build up (eg tension at the fault/boundary)

Do earthquakes have a long or short duration?

Earthquakes have a short duration of roughly 30 seconds but aftershocks can go on for weeks or months (Christchurch NZ)

What is the speed of onset like for earthquakes?

There is little warning and the shaking of the ground is almost immediate

What is the areal extent of earthquakes?

Roughly 20/30km (locally), but tsunamis can have an areal extent of the entire ocean (eg Japan 2011 tsunami impacting Antarctica)