Ex-LA Science Teacher Shares Theory On When Big Earthquakes Occur

April 30, 2014

LOS ANGELES (CBSLA.com) — A former Los Angeles science teacher has a theory on when big earthquakes are more likely to occur.

David Nabhan, who spent 20 years as a junior high instructor in South Central, believes the forces of gravity and where the sun and moon are could determine large temblors.

"The lunar and solar tides would be aligned to perhaps trigger quakes on fault lines that are ready to rupture," he said.

Nabhan points to some deadly quakes in Southern California's past:

In 1933, a magnitude-6.4 quake struck Long Beach at 5:54 p.m. at dusk. It was a full moon.

In 1971, a 6.6-magnitude quake hit Sylmar at 6 a.m. at dawn. It was a full moon.

In 1991, a 5.8-magnitude quake hit Sierra Madre at 7:43 a.m. at dawn. It was a full moon.

"All those quakes took place at dawn or dusk or at new or full moons," Nabhan said.

Notably absent from Nabhan's list were the Whittier Narrows quake and the Northridge quake. While they both happened in the early morning hours, it was not within 36 hours of a full or new moon.

CBS2's Paul Magers spoke with U.S. Geological Survey seismologist Lucy Jones about predicting earthquakes.

"There's a very slight correlation. Not enough to predict any earthquake out of it," she said. "People try to make patterns out of anything that scares them. We haven't found anything that looks different before a big earthquake than other times. We get enough people sending us predictions. The slug trail lady who used to go out in her driveway and map out the slug trails in the morning and use that to predict where the next earthquake was going to happen."

Asked about earthquake weather, Jones said, "The reality is earthquakes happen 5 to 10 miles deep in the earth and surface weather doesn't affect anything at that depth."

Asked what causes a quake to start and stop, she said, "I don't know. We have figured out that earthquakes are happening at much lower stresses, and now we're trying to understand the mechanisms that let them happen."

Jones is the new science advisor to Mayor Eric Garcetti and her priority is to develop earthquake preparedness recommendations for the city of Los Angeles, hopefully before the next "Big One."

Jones also hopes to increase safety awareness by identifying the Southland's critical infrastructure failure points.

"Eighty percent of Los Angeles' water comes across the San Andreas fault and aqueducts. And the assessment is that it will take 12 to 18 months to repair them from the extent of damage that's going to happen in the earthquake," she said.

While scientists continue to research earthquake mechanisms, Jones said there are benefits to an early warning system.

The system, developed at Caltech, is operational in Japan, Taiwan, China and Mexico. In California, the prototype has been running for two years.

"We're worried about the pipelines crossing the San Andreas. We could put up valves, to turn off the gas before the pipeline ruptures when the fault moves," Jones said.

While scientists cannot predict and do not know when the next earthquake will happen, Jones wants everyone to prepare.

"This isn't something you have to be afraid of. L.A. is worth the earthquakes, as long as we're ready for them," she said.

For tips on earthquake preparedness, visit earthquakecountry.org/prepare.

Video available at source:

http://losangeles.cbslocal.com/2014/04/30/ex-la-science-teacher-shares-theory-on-when-earthquakes-occur/
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