An undersea earthquake off the coast of Russia caused automated seismic monitoring systems to falsely report smaller earthquakes in California and Idaho on Monday.
The Russian quake caused seismic stations along the west coast to send out false computer-generated quake warnings, including reports of temblors in Big Bear and Central California. The real earthquake reached an initial magnitude of 7.3 when it struck the Sea of Okhotsk, west of Russia’s Kamchatka Peninsula, according to the U.S. Geological Survey.
The falsely identified U.S. earthquakes were deleted after seismologists reviewed the computer reports, said geophysicist Julie Martinez of the USGS National Earthquake Information Center in Colorado.
An earthquake as large and deep as that in Russia, no matter how distant, can sometimes confuse faraway seismic stations, said Kate Hutton, a seismologist at the California Institute of Technology.
“We know it’s a problem,” added Hutton, noting also that scientists are always called to verify computer-generated reports. The false reports that followed the Russian quake, for example, contained standard cautions stating that they had not yet been verified by seismologists.