If the oarfish, purple giant sea slugs, dolphins and tuna crabs washing up dead on the shores of southern California didn’t scare you, maybe this will. Geologists monitoring a portion of the Newport-Inglewood Fault Zone in the Los Angeles Basin have found unusual leaks of helium-3 (3He), a sign that the fault is much deeper than they previously thought. How deep? Deep enough to produce a magnitude-8 earthquake. Are you scared yet?
UC Santa Barbara geologist Jim Boles was sampling gas from two dozen oil wells between Los Angeles and Newport Beach, a 30 mile stretch. He found that the deepest wells, over one-third of those he analyzed, showed the presence of helium-3 and carbon dioxide (CO2) which carries the helium-3. This combination of gases indicates that the fault reaches deep into the Earth’s crust to the mantle. It also shows that the Newport-Inglewood fault is in a spot where two tectonic plates collide.
According to Boles’ report in the current edition of “Geochemistry, Geophysics, Geosystems,” these discoveries are surprising because the Newport-Inglewood fault is over 40 miles west of the plate boundary of the San Andreas Fault System and previous studies indicated that it was not deep enough to be a high-risk fault. As a result, Boles includes this warning:
This paper shows that the mantle is leaking more at the Newport-Inglewood fault zone than at the San Andreas Fault, which is a new discovery.
You read that right … leaking more than the San Andreas Fault. Based on that, the U.S. Geological Survey has increased the chance of magnitude-8 earthquake occurring in California in the next 30 years from 4.7 percent to 7 percent.
What’s worse, the southern portion of the San Andreas Fault from central California to the Mexican border hasn’t had a major quake in over 300 years and is overdue. This new discovery of the depth of the Newport-Inglewood fault increases the possibility of two or more faults quaking at once, magnifying the seismic energy and destruction.
NOW are you scared?