Earthquakes can also trigger tsunamis by unleashing underwater landslides, which also displace huge amounts of seawater.In this photo taken by a tourist Eric Skitzi from England, tourists watch as tsunami waves hit the shore from a safe place inside Casuarina Beach Hotel resort in Penang, northwestern Malaysia around pm in local time (0500GMT) Sunday, Dec. The resort hotel lifeguards noticed waves were huge and sounded warning to all tourists around the hotel beach area to run to the safety area.
"There have been some very successful forecasts based on the seismic gap theory," Wdowinski said.
Even without such forecasts, there are some basic things that can be done to prepare for an earthquake.
Earthquakes from 7 to 8 are major; about 15 of these occur annually.
Every year, at least one earthquake with a magnitude over 8 — a "great" quake — wreaks havoc.
In many cases, animals are simply sensing the arrival of earthquake waves that go unnoticed by people.
However, scientists can identify locations that are likely to experience earthquakes in the future.
Then the rocks on either side of the fault suddenly rip apart, sometimes at supersonic speeds.
The two sides of the fault slide past one another, releasing the pent-up pressure.
An earthquake's magnitude is ranked on the moment magnitude scale, not the Richter scale.
The moment magnitude scale provides a better idea of the shaking and possible damage from earthquakes of all kinds around the world. ]Earthquakes with magnitudes less than 3 occur every day, and are generally not felt by people.