San Andreas

Buried beneath the tracts of desert-colored homes with shingled roofs, wide streets and big yards, rests the mighty San Andreas fault, a geological menace responsible for two of the greatest earthquakes in California history. For Karmen Garcia and her two dogs, Dino and Sparky, this is home. "You can't see it here, but I know it's there," said Garcia, 45, as she walked her dogs along Bayberry Street. I think about it every day." Garcia laughed at the irony.

The fault that triggered a magnitude 8.2 quake off the northern Chilean coast was overdue for a significant earthquake, and an even more powerful temblor could be in store, said Rick Allmendinger, a Cornell University  professor of earth and atmospheric sciences. “This segment in Chile had not broken since 1877,” said Allmendinger, a geology expert who has extensively studied the northern Chilean fault zone. “It had been quiet for an unusually long period of time.” But the 8.2 earthquake, which seismologists said struck about 950 miles north of Chile's capital, Santiago, wasn't powerful enough to release all the friction that had been built up in this zone, where the Nazca plate is sliding underneath the South America plate, Allmendinger said.

Researchers believe Colorado River damming projects that followed the creation of the Salton Sea could be one reason why Southern California is overdue for a major earthquake. In a new study led by the Scripps Institution of Oceanography, scientists found that the floodwaters that periodically flowed through faults helped trigger earthquakes in the area, including several large ones along the mighty San Andreas. The modern Salton Sea came to life nearly a century ago when record floodwaters from the Colorado River overwhelmed barriers, and during the course of two years created the massive body of water in a desert sink.

The magnitude 5.1 earthquake that rattled Southern California on Friday was a 10-second reminder of a fault that seismologists believe can produce a catastrophic disaster. The Puente Hills thrust fault is so dangerous because of its location, running from the suburbs of northern Orange County, through the San Gabriel Valley and under the skyscrapers of downtown Los Angeles before ending in Hollywood. Experts say a major, magnitude 7.5 earthquake on the fault could do more damage to the heart of Los Angeles than the dreaded Big One on the San Andreas fault, which is on the outskirts of metropolitan Southern California.

Southern California is long overdue for a major earthquake along the San Andreas fault, according to a landmark study of historic seismic activity released Friday. The study, produced after several years of field studies in the Carrizo Plain area about 100 miles northwest of Los Angeles, found that earthquakes along the San Andreas fault have occurred far more often than previously believed. For years, scientists have said major earthquakes occurred every 250 to 450 years along this part of the San Andreas.

Mention earthquakes and Orange County residents look to the notorious San Andreas Fault, 30 miles northeast of the Los Angeles metropolitan area. Yet experts say a greater danger lies underfoot the Newport-Inglewood Fault slicing north along the Orange County coast from Newport Beach. It has already provided the worst urban quake in Southern California history--the 1933 Long Beach Earthquake that killed 120 people and caused $40 million damage. Yet that 6.

Scientists increased their watch along the San Andreas fault near Parkfield in Central California Monday after a 3.5 earthquake occurred in a particularly sensitive zone where a magnitude 6 quake has been predicted since 1985. Bill Ellsworth of the U.S. Geological Survey said the quake at 4:28 p.m. Sunday was centered on the San Andreas fault under Middle Mountain, seven miles northwest of Parkfield. The predicted strong temblor under the mountain is at least four years overdue.

Earthquakes along the San Andreas fault over the last 1,000 years have all been above magnitude 6.5, with no signs of small temblors that might have relieved pent-up pressure, scientists reported in the current issue of the journal Geology. By matching up dry creek beds on either side of the fault 120 miles northwest of Los Angeles, the researchers estimated that 95% of the slippage in the last six earthquakes was caused by large but rare quakes with magnitudes of about 7.5 to 8.

A respected earthquake authority reported Wednesday that he successfully predicted four moderate earthquakes on the San Andreas fault in Central California between October and January, raising the possibility that researchers may have discovered a way to give advance notice of the devastating shudders in the Earth.

The San Andreas is the glamour fault, the crease in California's surface that grabs the headlines. But it is the lesser-known Newport-Inglewood Fault, which runs through the heart of coastal Orange County, Long Beach and West Los Angeles, that scientists say may deliver the really Big One. Geologically, the two faults are cousins.

The geothermal power plants at Southern California's Salton Sea don't just produce electricity, they also trigger thousands of temblors not far from one of the West Coast's most dangerous earthquake faults, a new study says. Research published online Thursday in the journal Science found that as production rose at the Imperial County geothermal field, so did the number of earthquakes. From 1981 through 2012, more than 10,000 earthquakes above magnitude 1.75 were recorded in the area.

In the movie “Galaxy Quest” (a cult classic comedy ; I give it 3 stars and a big thumbs-up), the hero gains access to a device that allows him to reverse time. The catch? It's for just 13 seconds. What good would it do to be able to go back in time just 13 seconds, you -- and the “Galaxy Quest” hero -- ask? Well, see the movie and find out. (No spoiler alert needed.) Then perhaps you can also explain to me why we shouldn't get behind the plan to build an early warning system for earthquakes, which a group of California's top geophysicists and seismologists announced Monday.

For decades, scientists have assumed the central portion of California's San Andreas fault acts as a barrier that prevents a big quake in the southern part of the state from spreading to the north, and vice versa. As a result, a mega-quake that could be felt from San Diego to San Francisco was widely considered impossible. But that key fault segment might not serve as a barrier in all cases, researchers wrote Wednesday in the online edition of the journal Nature. Using a combination of laboratory measurements and computer simulations, the two scientists showed how so-called creeping segments in a fault - long thought to be benign because they slip slowly and steadily along as tectonic plates shift - might behave like locked segments, which build up stress over time and then rupture.

EUROPE Learn the ins and outs of riding the rails in Europe with Distant Lands' rail agent Susan Hickman. When, where : 7:30 p.m. Monday at Distant Lands, 20 S. Raymond Ave., Pasadena. Admission, info: Free. (626) 449-3220. SNOWSHOEING Workshop Experts will discuss snowshoeing basics such as selecting gear and where to go to get started. When, where: 7 p.m. Wednesday at the REI store in Arcadia, 214 N. Santa Anita Ave., and 6:30 p.m. Thursday at the REI store in Huntington Beach, 7777 Edinger Ave. Admission, info: Free.

An "earthquake storm" continued to rattle Imperial County late Sunday, with the region experiencing hundreds of mostly low-intensity temblors that could be felt in neighboring counties. The seismic activity is not unusual for the area around Brawley, a city of about 25,000 where the quakes were centered and located between the San Andreas and Imperial faults, experts said. The spurt of smaller quakes does not necessarily herald that the Big One is on its way, they said. After a series of milder quakes in the morning, a magnitude 3.8 temblor hit at 10:02 a.m. about three miles northwest of Brawley, and was followed by a nearly continuous series of quakes in the same general area, according to the U.S. Geological Survey.

CARRIZO PLAIN NATIONAL MONUMENT, Calif. - In his obsession to see every back road in Southern California, my brother, John, recently said, "Let's go to Carrizo Plain. " "Where's that?" I asked. He waved his palm in the air. "Over there. " Meaning, I gathered, someplace between Bakersfield and Santa Barbara. The website for the Bureau of Land Management, which helps administer Carrizo Plain National Monument, offers more precise directions, though it begins by warning visitors not to use GPS mapping software to get there.

Scientists trying to analyze the ongoing Southern California earthquake sequence focused their interest Monday on a section of the San Andreas Fault after several aftershocks were detected near the state's longest and most infamous quake zone. Cautioning that they cannot be certain what it all means, Caltech and U.S.

Thanks to a new method of modeling earthquakes, scientists may now understand why the Parkfield segment of the San Andreas fault - a carefully studied region known for producing moderate temblors every 20 years or so - has been behaving unexpectedly since around the time Ronald Reagan was in the White House. Taking data collected by sensors on the ground and in space and combining them with observations from laboratory physics experiments, Caltech researchers conducted a computer simulation of tectonic events at Parkfield and discovered that a series of small quakes there may have staved off a larger shaker that geologists predicted would occur in the late 1980s or early 1990s.

Researchers believe Colorado River damming projects that followed the creation of the Salton Sea could be one reason why Southern California is overdue for a major earthquake. In a new study led by the Scripps Institution of Oceanography, scientists found that the floodwaters that periodically flowed through faults helped trigger earthquakes in the area, including several large ones along the mighty San Andreas. The modern Salton Sea came to life nearly a century ago when record floodwaters from the Colorado River overwhelmed barriers, and during the course of two years created the massive body of water in a desert sink.