Although scientists cannot predict when or where the next major earthquake will occur, the U.S. Geological Survey produces hundreds of earthquake scenarios to help us plan for the inevitable. We worked with three experts from the USGS to select 14 significant earthquake scenarios on faults across California. Some we chose because they have been heavily studied by emergency officials; others we chose to represent the seismic risk across the state.
Use the map below to see which scenario would cause the worst shaking for where you live.
|Weak or less||Light||Moderate||Strong||Very strong||Severe||Violent shaking|
This map shows what may be among the worst case scenarios of shaking you could feel at a particular address. Downtown Long Beach, for instance, would feel severe shaking from a plausible magnitude 7.2 quake on the Newport-Inglewood fault, which runs through the city. By contrast, the magnitude 8 scenario we chose to map on the southern San Andreas fault — about 50 miles away — would bring strong shaking to downtown Long Beach.
There may be worse shaking scenarios possible than the ones we illustrated above. To keep the interactive map running fast, we chose just 14 out of more than 300 earthquake scenarios available for the California area.
Some earthquake scenarios are more likely to occur in our lifetime than others. If you want to see what can happen in your part of California, look at this map showing the relative earthquake shaking potential across the state.
There are roughly 30,000 miles of faults cutting across California, but the three fault sections that most concern many seismologists are the San Andreas, San Jacinto and Hayward. As they continue to build up seismic stress, ruptures become more and more likely. These faults are located near the Bay Area and Los Angeles, and big earthquakes on them could potentially displace hundreds of thousands of people.
The data for this project comes from the 2014 National Seismic Hazard fault database, published every six years by the USGS. This database contains nearly 800 scenarios, of which more than 300 take place within California's borders or along the coast.
To produce these scenarios, the USGS evaluates the likelihood of earthquakes on active faults across the country. Each earthquake scenario estimates shaking intensities for affected populations by assuming a certain magnitude, location, fault-rupture geometry, and then factoring in other variables like geology and local site soil conditions. These scenarios are most often utilized by emergency response organizations, utilities and local governments to prepare for realistic earthquake response situations.
What kind of damage could a big California earthquakes bring? Here’s a sampling of various scenarios studied by officials:
Although seismologists cannot predict when or where the next big earthquake will hit, it is essential to prepare for the worst. Read the linked articles below for steps you can take today:
Relatively more likely scenarios
Times staff writer Rong-Gong Lin II also contributed to this report.
Notes: Shaking intensity is calculated using the Modified Mercalli Intensity Scale. Likelihood of earthquake scenarios classified by USGS research geophysicist Eric Thompson.
Sources: U.S. Geological Survey, City of Los Angeles Hazard Mitigation Plan, San Diego Regional Chapter of the Earthquake Engineering Research Institute, UC Berkeley.
Credits: Priya Krishnakumar, Jon Schleuss and Thomas Suh Lauder contributed to this report.