Southern California ShakeOut

The Great Southern California ShakeOut earthquake drill is based on a magnitude 7.8 scenario earthquake on the San Andreas fault in southern California. This portion of the San Andreas fault has been identified as the most likely source of a very large earthquake in California (Working Group on California Earthquake Probabilities). As part of the earthquake drill, computer simulations of the ground shaking from this scenario earthquake were constructed through a collaborative effort between the USGS and the Southern California Earthquake Center, which involved researchers from the USGS, URS Corporation, San Diego State University, and Carnegie Mellon University. These computer simulations capture the shaking at length scales larger than about 300 ft (100 m) and provide detailed pictures of the shaking for this scenario earthquake.

The magnitude 7.8 scenario earthquake ruptures 186 miles (300 km) of the San Andreas fault from Bombay Beach at the edge of the Salton Sea in the south to Lake Hughes northwest of Palmdale in the north. The final slip (offset across the fault) ranges from 6-23 ft (2-7 m). The colors in the movies indicate the peak intensity of the shaking up to the current time at each location. SeeExplanation of Colors for a more detailed description of the color scheme.

Viewing the movies requires a media player, such as QuickTime Player, capable of displaying QuickTime movies. The movies are available in three different resolutions. The low resolution versions movies are typically 5-10 MB in size. The high resolution versions are typically 10-20 MB in size and best downloaded using a high-speed internet connection. The high definition (HD) versions are typically 50-80 MB in size and are best viewed on high resolution displays.

These images and movies are in the public domain and may be used freely. Please credit the U.S Geological Survey and the Southern California Earthquake Center.

Map View

This movie shows a view of southern California with the seismic waves radiating outward from the fault as the rupture propagates towards the northwest along the San Andreas fault.

Detailed Perspective Views

The detailed, perspective views show the ground shaking from a viewpoint two miles (three kilometers) above the earth looking towards each location. In each movie the left panel shows a map view of the area with the fault rupture highlighted in red, the epicenter (location where the rupture starts) identified by the red ball, and the location shown in the right panel labeled in yellow. In the right panel the deformation of the ground associated with the propagation of the seismic waves is exaggerated by a factor of 1000. The topography has been exaggerated by a factor of two to make the hills and mountains more readily visible.

Click on the map to view the low resolution movie for that location. Higher resolution versions are available below.

The displacement offset across the fault caused by the earthquake rupture is clearly evident in the Cajon Pass and Palm Springs views. It is visible, but less so, in the Ontario and Lancaster views.

The table below gives the maximum displacement (how much the ground moves) and maximum velocity (how fast the ground moves) for a point in the foreground in each of the perspective views.

Maximum Displacements and Velocities in Perspective Views
Location	Max. Displacement	Max. Velocity
Buena Park	0.8 m (3 ft)	0.6 m/s (2 ft/s)
Burbank	0.5 m (2 ft)	0.5 m/s (2 ft/s)
Cajon Pass	3.1 m (10 ft)	1.9 m/s (6 ft/s)
Corona	0.5 m (2 ft)	0.5 m/s (2 ft/s)
Huntington Beach	0.7 m (2 ft)	0.6 m/s (2 ft/s)
Lancaster	1.9 m (6 ft)	1.4 m/s (5 ft/s)
Long Beach	0.5 m (2 ft)	0.6 m/s (2 ft/s)
Los Angeles	0.7 m (2 ft)	0.6 m/s (2 ft/s)
Marina del Rey	0.5 m (2 ft)	0.4 m/s (1 ft/s)
Ontario	0.8 m (3 ft)	0.6 m/s (2 ft/s)
Palm Springs	1.3 m (4 ft)	1.3 m/s (4 ft/s)
Ventura	0.7 m (2 ft)	0.5 m/s (2 ft/s)
Watts	1.2 m (4 ft)	1.2 m/s (4 ft/s)
Woodland Hills	0.4 m (1 ft)	0.3 m/s (1 ft/s)