Magnitude 4.0 Quake Rattles San Francisco Bay Area, Major Quake Expected 'Any Day Now'
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Magnitude 4.0 earthquake rattles San Francisco Bay area - Yahoo News
A 4.0 magnitude earthquake shook the San Francisco Bay area on Tuesday and spooked residents, although officials said there were no immediate reports of serious damage or injuries.
The quake struck around 2:40 a.m. local time and was centered just outside of Fremont, some 30 miles southeast of San Francisco, according to the U.S. Geological Survey.
A series of about a dozen smaller quakes followed, with magnitudes ranging from 1.0 to 2.7 through the early morning hours, the USGS said.
The shaking caused brief delays across the Bay Area Rapid Transit train system as workers checked the tracks for damage, the system said.
California, which sits along a series of seismic faults, is forecast to experience a much more powerful earthquake at some point, but scientists do not know when it might come or how strong it might measure.
USGS Scientist: Major Quake On Hayward Fault Expected ‘Any Day Now’ « SF Weekly News
You may have slept through last night's 4.0 magnitude earthquake, but at least one U.S. Geological Service scientist wants to make sure you don't sleep again.
Tom Brocher, a scientist with the USGS, told CBS that the Hayward Fault, which produced last night's trembles, is due to produce a major earthquake "any day now."
Per CBS:
“The population is now 100 times bigger in the East Bay, so we have many more people that will be impacted,” said Tom Brocher, a research geophysicist with the USGS.
“We keep a close eye on the Hayward Fault because it does sit in the heart of the Bay Area and when we do get a big earthquake on it, it’s going to have a big impact on the entire Bay Area,” Brocher said.
While a 2008 report put the probability of a 6.7-magnitude or larger earthquake on the Hayward-Rodgers Creek Fault system over the next 30 years at 31 percent, Brocher said the reality is a major quake is expected on the fault “any day now.”
“The past five major earthquakes on the fault have been about 140 years apart, and now we’re 147 years from that 1868 earthquake, so we definitely feel that could happen any time,” Brocher said.
Bocher has been sounding the alarm on the Hayward Fault for a while now. In 2008, he was the lead author of a USGS report that described the fault as a "tectonic time bomb" and warned that a 6.8-7.0 magnitude quake could "could cause hundreds of deaths, leave thousands homeless, and devastate the region’s economy." Among the factors that lead the report's authors to suggest that the Hayward Fault is the country's most dangerous one are the facts that it is the "single most urbanized earthquake fault in the United States" and that "critical regional gas and water pipelines and electrical transmission lines cross." You can read the full report here [pdf].
And if that doesn't freak you out enough, have you checked out the USGS liquefaction maps for your neighborhood? About 25% of the Bay Area is considered to have Very High, High or Moderate susceptibility to liquefaction.