Scientists have detected a large amount of Helium leaking from a huge fault in the Earth’s crust near Los Angeles is leaking helium. They say the unexpected find sheds new light on the Newport-Inglewood Fault Zone in the Los Angeles Basin, showing that the fault is far deeper than previously thought, and a quake would be far more devastating. The find follows a report from the U.S. Geological Survey that warned the risk of ‘the big one’ hitting California has increased dramatically.
The Newportâ€“Inglewood Fault extends for 75 kilometers (47 mi) from Culver City southeast to Newport Beach at which point the fault trends east-southeast into the Pacific Ocean
The discovery was made while testing samples of casing gas from two dozen oil wells ranging from LA’s Westside to Newport Beach in Orange County, Boles discovered that more than one-third of the sites show evidence of high levels of helium-3 (3He).
‘The Newport-Inglewood fault appears to sit on a 30-million-year-old subduction zone, so it is surprising that it maintains a significant pathway through the crust.’ Considered primordial, 3He is a vestige of the Big Bang, and its only terrestrial source is the mantle. When Boles and his co-authors analyzed the 24 gas samples, they found that high levels of 3He inversely correlate with carbon dioxide (CO2), which Boles noted acts as a carrier gas for 3He.Â An analysis showed that the CO2 was also from the mantle, confirming leakage from deep inside the Earth.
‘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.’ The study’s findings contradict a scientific hypothesis that supports the existence of a major dÃ©collement â€” a low-angle thrust fault â€” below the surface of the LA Basin.Â ‘We show that the Newport-Inglewood fault is not only deep-seated but also directly or indirectly connected with the mantle,’ Boles said.
Researchers analyzed the latest data from the state’s complex system of active geological faults, as well as new methods for translating these data into earthquake likelihoods. The estimate for the likelihood that California will experience a magnitude 8 or larger earthquake in the next 30 years has increased from about 4.7% to about 7.0%, they say.
‘We are fortunate that seismic activity in California has been relatively low over the past century,’ saidÂ Tom Jordan, Director of the Southern California Earthquake Center and a co-author of the study. ‘But we know that tectonic forces are continually tightening the springs of the San Andreas Fault system, making big quakes inevitable. ‘The UCERF3 model provides our leaders and the public with improved information about what to expect, so that we can better prepare.’
The new study, estimates the likelihood that California will experience a magnitude 8 or larger earthquake in the next 30 years has increased from about 4.7% to about 7.0%