Thread: Cali Earthquakes Predicted

Hayward Fault: Major Earthquake In San Francisco Expected 'Any Day Now'

The USGS set the record straight about the Hayward Fault panic.
By Suzette Gutierrez | Jul 24, 2015 09:42 AM EDT

Panic has erupted throughout social media, as earlier reports stated that San Francisco will experience a major earthquake "any day now."

The story came out after a 4.0 magnitude earthquake on the Hayward Fault rocked the Bay Area on Tuesday.

A U.S. Geological Survey scientist said that the fault is expected to result in a major earthquake "any day now" and advised Bay Area residents to be prepared, according to CBS San Francisco. The story quickly picked up on Facebook and became viral, spreading panic on social media and fear among the Bay Area residents.

The story was apparently sourced from the local news wire Bay City News, which reported that "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,'" SF Gate reported.

Tom Brocher, research geophysicist at the USGS Earthquake Science Center, set the record straight and clarified that a major earthquake can hit the Bay Area at any time, not any day now, as there is still no way to accurately predict when earthquakes will occur. "The Hayward fault is capable of producing a major earthquake at any time, but there is currently no scientific basis for making a prediction for when that earthquake will occur," Brocher said.

Brocher said the Uniform California Earthquake Rupture Forecast model has predicted that a magnitude 6.7 earthquake or greater may occur in 30 years along the Hayward-Rodgers Creek fault system. The model's prediction is at 31 percent probability.



Bay City News corrected its report, at Brocher's request, to read "Although the fault that produced a 4.0-magnitude earthquake in Fremont this morning is not expected to change the likelihood of another major quake on the same fault, a U.S. Geological Survey scientist said a major earthquake could happen at any time and residents should be prepared," according to SF Gate.

The last earthquake on the Hayward Fault occurred on Oct. 21, 1868 with a 6.8 magnitude. It was one of the most destructive quakes in the history of California, even though the Bay Area at the time was not as densely populated as it is today. Scientists said in a 2008 USGS Fact Sheet that the fault is "a tectonic time bomb, due anytime for another magnitude 6.8 to 7.0 earthquake."

http://www.hngn.com/articles/112403/...ed-day-now.htm

Cascadia Fault Line: Scientists Predict Powerful Earthquake That Could Devastate The Pacific Northwest

Scientists say the Pacific Northwest is 72 years overdue for a megaquake.

By Suzette Gutierrez | Jul 16, 2015 12:40 AM EDT

Many people are familiar with the San Andreas fault line in California; however, north of it lies a lesser known but a more potentially deadline fault line - the Cascadia fault line, also called Cascadia subduction zone.

Cascadia runs 700 miles off the Pacific Northwest coast. It starts from Cape Mendocino in California, extends through Oregon and Washington and ends in Vancouver Island in Canada. Its name was derived from the Cascade Range, a series of volcanic mountains found around 100 miles inland, running parallel with the subduction zone, according to The New Yorker.

A subduction zone is that place where two tectonic plates meet, with one sliding beneath the other.

In the Cascadia subduction zone, the oceanic plate Juan de Fuca is sliding beneath the North American tectonic plate, but the North American tectonic plate is stuck above Juan de Fuca's surface, causing it to bulge upward at a rate of three to four millimeters a year and compress eastward at a rate of 30 to 40 millimeters a year, The New Yorker explains.

If part of the Cascadia gets unstuck, an earthquake with a magnitude of 8 to 8.6 will be felt. However, if the entire Cascadia gets unstuck, an event called full-margin rupture, the resulting earthquake can have a magnitude of 8.7 to 9.2. The ground will drop 6 feet at most and move 30 to 100 feet westward as the ground releases the tension it had been subjected to for centuries. "As the two plates collide," geologist Ian Madin, head scientist at Oregon Department of Geology and Mineral Industries, explains, "the fault gets stuck, eventually slipping when enough stress builds up to produce a great earthquake," according to Fox 4 KC.

The earthquake is not the only problem scientists are predicting; a powerful tsunami will slam the Pacific Northwest coast 15 minutes after the earthquake hits and sweep over Sacramento all the way to Canada.

Kenneth Murphy, director of FEMA Region X, said that the devastation will be so great that "everything west of Interstate 5 will be toast." FEMA estimates a death toll of 13,000 people, with 27,000 more injured and an estimated total of 7 million people affected. "This is one time that I'm hoping all the science is wrong," Murphy said, according to The New Yorker.

Kevin Cuppies, city planner for Seaside, Ore., said that tourists and the elderly will face the greatest risk if the earthquake should occur. "We can't save them," Cuppies says. "I'm not going to sugarcoat it and say, 'Oh, yeah, we'll go around and check on the elderly.' No. We won't," he said, according to The Inquisitr.

Chris Goldfinger, a scientist who has been studying the Cascadia for years, said the odds of a powerful Cascadia earthquake happening in the next 50 years is one to three.

Goldfinger and other scientists conducted a study on seafloor samples and found out that the Pacific Northwest has had 41 subduction zone earthquakes in the last 10,000 years. Based on this pattern, the earthquakes happened every 243 years. The last one was in 1700, which means the Pacific Northwest is 72 years overdue for the next earthquake.

Goldfinger said preparation is the best way to cope with such a predicted event, but the region is nowhere near prepared for it. "The science part is fun, and I love doing it," Goldfinger said. "But the gap between what we know and what we should do about it is getting bigger and bigger, and the action really needs to turn to responding. Otherwise, we're going to be hammered," he added, according to The New York Post.

http://www.hngn.com/articles/109826/...-northwest.htm