LA's Fault System Actually In Quiet Period
The "urban fault network" under the Los Angeles metropolitan area--which does not include the San Andreas fault--is actually in a period of relative quiet. Steve Mirsky reports.
SUBSCRIBE TO Science Quickly
On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
This is going to surprise anybody who’s ever been shaken awake by a quake in southern California. But geologists say that the Los Angeles basin is actually in a period of low seismic activity and has been for about the last thousand years. That’s according to research published in the September issue of the journal Geology. The seismic lull is marked by relatively smaller and fewer earthquakes. That’s compared with other periods with a lot of rumbling and crumbling. The period of big seismic activity in the LA basin that ended a thousand years ago lasted about four thousand years. Long-term data on seismic activity indicates that the calm period lasts about 1500 to 2000 years, which gives LA another 500 to 1000 years off.
Now, the researchers are specifically referring to what’s called the urban fault network, which is under the LA metropolitan area. It does not include the San Andreas fault, which can still throw the occasional big one around. About 10 major San Andreas biggies have happened during the current LA basin lull. Nevertheless, if the current lull ends in the next millennium, LA’s future could be very shaky.
It’s Time to Stand Up for Science
If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.
I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.
If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.
In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.
There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.
