Is your city in the danger zone?

For Californians, the latest forecast from the U.S. Geological Survey and others is a mix of "oh, good" and "oh, crap." New models show a reduced risk of medium-sized quakes, and a jacked-up potential for really big ones.

But where's the next powerful earthquake likely to hit? And for those who want to avoid it at all costs, where's a good place to relocate?

The various entities behind the forecast—known collectively as the Working Group on California Earthquake Probabilities—have done a good job answering these dicey questions. For starters, they've made a map showing the seismic threat across the whole state. The red zones stand a significantly higher chance of being shaken like pudding from a 6.7 magnitude or larger quake in the next 30 years (that's the strength of the damaging 1994 Northridge temblor):

USGS et al.

Even more helpful, from a local perspective, are the Google Earth files showing troublesome faults running through cities (direct download). The color coding is the same—red is the danger zone—and if you zoom and click, you can see the estimated risks for your neighborhood.

Here's Berkeley, for instance. The hills just east of the university have a mean probability of 14.6 percent of a violent rupture in the next three decades:

South of San Francisco has a mean probability of 6.4 percent:

Fault-riddled Los Angeles is rife with quake scenarios. The highest I was able to find in the metro area is 3 percent near Long Beach:

However, to the east is the threatening San Andreas fault, which scientists say could transfer massive quantities of seismic energy to L.A. when it goes off. That large-scale event has a 20 percent mean probability:

The researchers who made this map say it's "inevitable" California will suffer destructive earthquakes in the future. They predict a medium-sized one is likely to occur an average of once every 6.3 years, and give the whole state a 7 percent chance of incurring a big one (8 magnitude or larger) in the next 30 years. For those who want to know why scientists are more concerned than ever about major quakes, these are technical details from the forecast:

Another clue with respect to the moderate-magnitude rate discrepancy is that many recent earthquakes have plowed past previously inferred fault-rupture boundaries. That is, past models have generally assumed that earthquakes are either confined to separate faults, or that long faults like the San Andreas can be divided into different segments that only rupture separately. However, all three of the most-recent, largest earthquakes in California ruptured right past such boundaries, jumping from one fault to another as multifault ruptures. These were the 1992 magnitude 7.3 Landers, the 1999 magnitude 7.2 Hector Mine, and the 2010 magnitude 7.2 El Mayor–Cucapah earthquakes. The 2011 magnitude 9.0 Tohoku, Japan earthquake also violated previously defined fault-segment boundaries, resulting in a much larger fault-rupture area and magnitude than expected, and contributing to the deadly tsunami and Fukushima nuclear disaster.

About the Author

Most Popular

  1. A photo of a cyclist on the streets of Chicago's Pilsen neighborhood.
    Equity

    Can Historic Preservation Cool Down a Hot Neighborhood?

    The new plan to landmark Chicago’s Pilsen neighborhood aims to protect more than just buildings: It’s designed to curb gentrification.

  2. A cat lays flat on a bench at a park on the outskirts of Tokyo.
    Life

    Why Don't Americans Use Their Parks at Night?

    Most cities aren’t fond of letting people use parks after dark. But there are good lifestyle, environmental, and safety reasons to reconsider.

  3. Rows of machinery with long blue tubes and pipes seen at a water desalination plant.
    Environment

    A Water-Stressed World Turns to Desalination

    Desalination is increasingly being used to provide drinking water around the globe. But it remains expensive and creates its own environmental problems.

  4. a photo of a woman covering her ears on a noisy NYC subway platform
    Life

    My Quixotic Quest for Quiet in New York City

    In a booming city, the din of new construction and traffic can be intolerable. Enter Hush City, an app to map the sounds of silence.   

  5. Design

    What Cities Can Do to Help Birds and Bees Survive

    Pollinators—the wildlife that shuffle pollen between flowers—are being decimated. But they may still thrive with enough help from urban humans.

×