Geologists keeping an eye on earthquake "swarm" in California
The USGS says the phenomenon makes a stronger quake more likely, though with still a very low probability.
Seismologists are keeping an eye on a "swarm" of small earthquakes in southern California, with some chance of a stronger quake -- though with a relatively low probability of a damaging one.
The U.S. Geological Survey (USGS) first detected the quakes on September 30 near the Salton Sea in the state's arid interior. That day, some 48 quakes of Magnitude 3 or greater rumbled beneath the region.
One, a Magnitude 4.9, remains the strongest detected during this swarm so far, though with no reports of damage or injuries.
Image: U.S. Geological Survey
The swarm continued through the week, though with only 13 such quakes on Thursday, and the USGS says the phenomenon increases the chance of a Magnitude 7 or greater quake happening in the next seven days -- however, that represents a 1 in 500 chance, as opposed to the 1 in 3000 chance in a given week, according to the agency.
A more likely outcome is that the small earthquakes, up to Magnitude 5.4, will continue (93 per cent chance) over the next seven days, with decreasing frequency, the USGS says.
"The swarm continues to evolve, and we expect to update this forecast with more specific probability information as we collect more data," the USGS said in its Friday report.