E ARTHQUAKE - RELATED H AZARDS

Strong ground motion from earthquakes can produce significant amounts of damage. These effects are especially problematic in regions with poorly built structures. M 7.6, Indonesia, September 2009

Padang, Indonesia September 30, 2009 M 7.6 Unprepared and poor building practices

Liquefaction Loose, sandy, wet soils beneath structures act like liquids when strongly shaken. In this photo, the house does not appear to have too much damage – except that it has tilted sideways! This is a concern for areas of Los Angeles in the event of a major earthquake on the southern San Andreas Fault. M 7.9, San Francisco, CA, 1906

M 7.5, Niigata, Japan, 1964 These buildings were built on sand. The earthquake occurred about 50km from Niigata, but the damage in Niigata was extensive. Changes in the soil caused most of the damage.

Damage and fatality rates due to strong shaking are generally controlled by: size of earthquake distance from earthquake depth of earthquake location of earthquake – land – ocean – type of plate boundary local geology local building codes population density time of day

Some earthquakes produce devastating landslides. Image by W. Thompson M 7.6, Kashmir, 2005

M 7.6, El Salvador, 2001 M 6.8, Nisqually, WA, 2001

Tsunamis can be produced when vertical motion occurs on faults beneath bodies of water. These images show boats remaining on land after the tsunami occurred. M 9.3, Sumatra, 2004

M 7.4, Alaska, 1946 Tsunamis can produce devastating damage very far from the location of the earthquake. This image is from Hilo, Hawaii, and was taken during the tsunami generated by the 1946 Alaska earthquake.

Fires caused as much as 90% of the total damage in the 1906 San Francisco earthquake; many of these were due to ruptured gas lines. M 7.9, San Francisco, CA, 1906

Floods: A landslide created a natural dam following the Sichuan earthquake. Communities downstream had to be evacuated due to flooding after the water pushed through. M 8.0, Sichuan, China, 2008

Additional complications can occur after earthquakes: Health and disease problems due to poor sanitation Pollution and other environmental effects Famine, if food production is compromised Exposure as a result of not having sufficient protection from the climate