Pipelines from a proposed deepwater liquefied natural gas terminal off Southern California's coast face a 16-48% probability of a damaging earthquake within 30 miles of their route, a US Geological Survey report said on Dec. 23.
It said that while the US Department of the Interior agency does not make recommendations for or against proposed projects, researchers found that the probability of an earthquake measuring 6.5 or above on the Richter scale along the OceanWay Secure Energy Project's planned pipeline route in Santa Monica Bay ranged from 16% at its origin 23 miles offshore to 48% at its planned termination near Los Angeles International Airport.
"Earthquakes of this size can cause damage over a large region," said the report, citing impacts of the 1994 Northridge quake which measured 6.7 points at its epicenter.
It said that the proposed deepwater LNG project would be situated in 3,000 feet of water and be connected to onshore systems by twin 24-inch diameter pipelines to onshore systems 35 miles away. Facilities would include a deepwater port including submersible buoys, manifolds and risers, it indicated.
The deepwater terminal would be 27 miles from the Los Angeles coastline and more than five miles from shipping lanes, according to the project's sponsor, Woodside Natural Gas of Santa Monica, Calif. It said that the regasified LNG would be delivered onshore into an existing Southern California Gas Co. system. Woodside Natural Gas is a subsidiary of Woodside Petroleum Ltd., a worldwide oil and gas producer based in Perth, Australia.
The USGS report said that the proposed project's pipelines would face hazards from potential sea floor offsets because they cross at least two faults, as well as tsunamis, erosion or scouring, shallow gas deposit venting and pipeline settling.
It said that 27 scientists from the USGS and the California Geological Survey reviewed regional geologic hazards identified in a 2007 report prepared by Fugro West Inc. as part of OceanWay's 2007 deepwater port application. US Rep. Jane Harmon (D-Calif.) also requested information on geologic hazards which should be considered in connection with the proposed project in a March 25 letter to USGS, the report indicated. Further information is available online at www.usgs.gov under Latest Publications.
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