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Beijing time on July 7, news, according to the British Daily Mail report, researchers found that a huge fault in the crust near Los Angeles is leaking helium. They said this unexpected discovery will provide new insights into the Newport-Inglewood fault zone in the Los Angeles Basin. This reveals that the fault is deeper than expected and the resulting earthquake will be more destructive. This stems from a report by the United States Geological Service, which warned that the risk of a "bigger" earthquake hitting California has greatly increased.

13bc33e35beebfb_size53_w634_h263The Newport-Inglewood fault zone extends 75 kilometers southeast of Culver City to Newport Beach, where the fault extends from the east-southeast to the Pacific Ocean. Geologist Jim Boles, emeritus professor of the School of Earth Sciences at the University of California, Santa Barbara, discovered evidence of helium leakage in the mantle of the 30-mile extension of the Newport-Inglewood fault zone in the Los Angeles Basin . He claimed that this result shows that the Newport-Inglewood fault zone is deeper than expected. Using casing gas samples from twenty-four oil wells—from the West Side of Los Angeles to Newport Beach in Orange Town—Boles found evidence of higher helium-3 levels in more than one-third of the locations. "For some areas, these results are very unexpected, because the Los Angeles Basin is very different from where most mantle helium anomalies occur," Bols said. "The Newport-Inglewood fault zone seems to be located in a 3000 million-year-old subduction zone, so it is very unexpected that it still has a huge passage through the crust." Considering that it is very primitive, helium-3 is a remnant of the Big Bang , Its only source of earth is the mantle. Borse’s discovery was published in the electronic journals Geochemistry, Geophysics and Earth System (G-Cubed) of the American Geophysical Union and the Geochemical Society.

fe59d8cadc8ba6a_size49_w634_h264When Bols and his co-authors analyzed 24 gas samples, they found that the high content of helium-3 is inversely related to the content of carbon dioxide. Bols believes that carbon dioxide is the carrier gas for helium-3. The analysis showed that the carbon dioxide also came from the mantle, which confirmed that the leak came from deep within the earth. The blue schist found in a nearby deep well indicates that the Newport-Inglewood fault zone is an ancient subduction zone--that is, where two plates collided--even though it is now located at the current plate boundary of the San Andreas fault system 40 miles to the west. The blueschist found at a depth of 20 miles is a metamorphic rock, which is only revealed when it flows back to the surface through geological upheavals.

f1abe79ffd67761_size57_w634_h398"About 3000 million years ago, the Pacific plate collided with the North American plate, creating a subduction zone in the Newport-Inglewood fault zone." Bols explained. "Then, for some reason, the junction moved to the current San Andreas fault, although exactly how this happened is still unknown. This article shows the mantle of the Newport-Inglewood fault zone. There are more leaks than the San Andreas fault. This is a new discovery.” This discovery contradicts a scientific hypothesis that believes that there is a major de-topping fold under the surface of the Los Angeles Basin, the latter being a Slowly dipping thrust fault. "We found that the Newport-Inglewood fault zone is not only very deep, but also directly or indirectly connected to the mantle."

58369cfa2128ef5_size60_w634_h421"If the protruding fold exists, then it should cross the Newport-Inglewood fault zone, but this possibility is very low." Bols added. "Our findings indicate that the Newport-Inglewood fault zone is more important than expected, but time will tell us its true importance." The researchers analyzed the latest data on the complex system of active geological faults in California, and These data are transformed into a new method of earthquake possibilities. The probability of an earthquake of magnitude 30 or higher in California in the next 8 years is estimated to increase from 4.7% to 7%.


"In the past century, California's seismic activity has been relatively low, and we are really lucky," said research co-author Tom Jordan, director of the Southern California Seismic Center. "But we know that plate forces are continuing to tighten the springs of the San Andreas fault system, which makes the occurrence of major earthquakes inevitable." "The Third Unified California Seismic Fracture Prediction (UCERF3) model is our leader and the public Provides information about future expectations so that we can better prepare." UCERF3 has further improved the previous by adding the latest data from the complex system of active geological faults in California and a new method to convert these data into seismic possibilities. model. This study confirmed many previous findings and provided the possible distribution and possible magnitude of earthquakes throughout California in the future.


与2008年发布的早先估计UCERF2相比,目前估计的地震震级大约为6.7——相当于1994年美国加州圣费南多谷地北岭地震的震级——已经减少了30%。整个加州这种事件预计的发生频率从平均每4.8年发生一次减少到每6.3年一次。然而,在这项最新研究里,未来三十年内加州经历震级8级以上地震的可能性从UCERF2的4.7%增加到UCERF3的7.0%。“最新的可能性数据是基于可能的多断层断裂,也即地震不再受限于单独的单个断层,而是可能偶尔发生多个断层同时断裂。”研究首席作者、美国地质调查局的科学家奈德•菲尔德(Ned Field)这样说道。

14357708499993"From the perspective of reflecting the larger range of earthquakes in the entire California complex fault system, this is a major development." Two types of scientific models are used to assist decision-making on how to reduce earthquake losses: earthquake fracture prediction and ground motion For the prediction model, the former implies the time and location of many faults in California, and the latter can estimate ground shaking based on one of the faults. UCERF belongs to the former and is also California's latest earthquake-fracture prediction. It was proposed and reviewed by dozens of scientific experts from the fields of seismology, geography, geodesy, paleoseismology, seismic physics and seismic engineering. Lucy Jones, a seismologist with the U.S. Geological Survey and an earthquake consultant to Los Angeles Mayor Eric Garcetti, tweeted about the randomness of large earthquakes last Tuesday. "This new science will not change the bottom line of emergency management personnel. Which earthquake will occur in our lives is a random subset." Jones wrote. (Compile / Yan Yan Liu Xing)

Article reprinted from Phoenix Network Technology


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