Great ShakeOut Earthquake Drills

Southern California (West) Earthquake Hazards

The Southern California (West) area is highly susceptible to earthquakes and earthquake related effects. Numerous earthquake faults crisscross southern California and no one within the area resides more than 10 miles from an active fault. In addition to damage caused directly by groundshaking and related groundfailure, other hazards such as fires can easily start during and shortly after an earthquake.

Designed for the original ShakeOut in 2008, the ShakeOut Scenario portrays a magnitude 7.8 earthquake along the southern San Andreas fault. Much more can still be learned in preparing for such a large earthquake! The Scenario is a product of the United States Geological Survey, Multi-Hazard Demonstration Project, led by Dr. Lucy Jones.

Fires may spread quickly in densely-built neighborhoods, enabling them to sustain for long periods, spread over large areas and, due to broken water pipes and the number of ignitions, simply overwhelm the abilities of firefighters to control them. On the other hand, earthquakes occurring during periods of heavy rain can produce destructive and life threatening slurry-like debris flows that originate on the steep slopes and gullies of the many rugged mountain areas and can flow into adjacent communities.

The driving force of earthquakes in California is movement along the San Andreas Fault and the many associated faults within the San Andreas Fault System that form the tectonic boundary between the Pacific and North American tectonic plates. Along this boundary, the Pacific Plate is moving slowly to the northwest relative to the North American Plate. The Pacific plate underlies most of the Pacific Ocean, as well as all California west of the San Andreas fault. When most people think of earthquakes in California, the San Andreas Fault is usually the first thing to pop in their minds, and while the San Andreas Fault is the longest fault in the state it is by no means the only one to be concerned with. Many other faults are found directly beneath our cities in some of the most densely populated areas.

Earthquake Shaking Potential,
Southern California (West) Area

Large earthquakes anywhere in the Southern California (West) area can affect you, even if the shaking is not strongly felt where you happen to be. Consider what might happen to the nation's economy if the harbors in Los Angeles and Long Beach were put out of commission, and the normal flow of goods were to be disrupted. What if a freeway overpass along your commute were to be heavily damaged or destroyed? How would you find drinking water if subsurface supply pipes are broken? We all must consider these and other plausible scenarios that can happen at any time and take measures that would minimize their impacts.

Because you live in the Southern California (West) area, it is likely that a damaging earthquake will occur and affect you during your lifetime. You decide your fate. You decide your future. The steps you take now can mean the difference between your success or failure after the next big quake. Start now!