Map highlights new California earthquake faults

More than 50 new surface earthquake faults have been discovered in California over the last two decades, according to a new state map that officials hope will help guide future development decisions and emergency planning.

The state’s fault activity map, produced by the California Geological Survey, is the first in 16 years and offers a sober reminder of California quake risks.

The new faults range from small ones that don’t pose much threat for major temblors to very large ones, such as the one responsible for the 7.1 Hector Mine earthquake that shook Southern California in 1999. Most of the faults have been known to researchers and contained in scientific files.

But state officials and quake experts hope that pulling all the faults together onto one map will educate the state about quake-risk zones and help residents grasp the geography of the fault lines. 

“I think every classroom in California should have these maps on the wall,” said Caltech seismologist Lucy Jones. “I don’t think we do enough to educate the general public about these features. We turn it into something for the specialists, as if science is only for scientists. But if you’re going to buy a house, would you like to know what fault is under your house?”

Roughly 50 new faults might not seem like a lot in a state with thousands of them. But experts said the new map points to a basic fact of seismology: The more scientists study quakes in California, the more faults -- and dangers -- they find.

“These maps are used to make a lot of other maps, to map landslides, areas where you have liquefaction because of earthquakes, for tsunami coastal mapping,” state geologist John Parrish said. “They can be used to make decisions on where to build schools and hospitals, where you need a higher standard of construction. They can tell you what kind of a surface you’re building on, and how close you are to a fault."

The map comes amid an increased interest in quakes in California and beyond. Last month’s 7.2 Mexicali quake produced thousands of aftershocks, including dozens registering more than magnitude 4.0. As a result, officials said 2010 is shaping up to have significantly more quakes greater than 4.0 than in the last decade.

Parrish said the map represents the state’s best efforts at compiling the faults across California and will hopefully be used to enhance earthquake preparedness.

Parrish and others stressed that residents should not necessarily be alarmed if they live or work near one of California’s estimated 15,000 faults. Many of the faults are fairly short, and experts have found no evidence they have produced sizable temblors. But others can produce major temblors.

Some of these faults were discovered after a large quake erupted in the area over the last two decades.

Scientists, however, found others through research and believe they have a history of major seismic activity that could date back thousands of years. The new faults are spread across the region, including some along the Santa Monica Bay and Orange County coast as well as some -- like Hector Mine -- in the Mojave desert.

One new fault of concern to seismologists is the Maacama fault, which runs along the coastal mountains of Northern California.

-- Hector Becerra

Comments

[James]

So, where's the map?

[Dave]

So where is the link to the new map?

[Dax Wagner]

Here's a brilliant idea LA Times: the next time you post an article about a map, try making that map a PRIMARY GRAPHIC for everybody to see! Especially when it comes to public safety. Do I have to come down there and run your newspaper for you? This is ridiculous.

[larry]

rather live in Calif and risk a major quake every 20 or 30 yrs than the tornadoes/hurricanes every year in the midwest and east coast.
Dont forget 40 below and six foot snow drifts either.

[JustSo]

No key for the map? Not so helpful.
I'm not sure if it means they "do can produce major tremblors" (sic)

[Susan]

Yeah, where can we get this map? I would like one for my office. I would also like to distribute this map to friends and family. How are we supposed to raise awareness?

[Kate]

Larry, having grown up in Nebraska... well, I can only agree with you.

Would be nice if the map were large enough to read, though.

[Kevin]

Did anyone proof this article before it was printed? There are multiple grammatical errors (subject/verb agreement in at least 2 cases).

As well, couldn't you explain why the Maacama Fault is of concern? You just ended the article with that blast of info without any explanation.

[Yvonne]

Ditto Larry.....and those yearly tornadoes, ice storms, bone-chilling cold and snow are reasons why I moved from Indiana to California 13 years ago

[syscom3]

Yes, wheres the map we can zoom into.

[freddie]

That headline is simply poor writing. They are "newly discovered faults" NOT "new faults". The faults have been there all along. We simply didn't know about them before.

[My opinon means nothing]

To all you former Mid-Westerners who blogged how bad it is in the winter back there and how happy you are to be here: Check out the article here that talk about how much better it is to find a job there than here in sunny southern California. You still like it here?