Warning: Quake Swarm Along the San Andreas

California is on high alert after a series of ‘mini quakes’ this week raised fears a ‘megaquake’ on the San Andreas fault could be coming.

A series of more than 35 temblors struck a rural area of Southern California near the U.S.-Mexico border in what seismologists call a ‘swarm’ of quakes.

The swarm dramatically increases the likelihood of a much more major quake in Southern California, at least temporarily, the U.S. Geological Survey said.

For the seven-day period following Tuesday, the chances of a magnitude-7 or greater earthquake being triggered on the southern San Andreas fault are as high as 1 in 100 and as low as 1 in 3,000.

‘This is close enough to be in that worry zone,’ seismologist Lucy Jones told the LA Times of the location of the earthquake swarm.

‘It’s a part of California that the seismologists all watch.’

The largest earthquake recorded by the U.S. Geological Survey was magnitude 4.3 at 7:31 a.m. and was centered 35 miles (58 kilometers) northwest of El Centro.

According to the Southern California Seismic Network, more than 35 small earthquakes were recorded Monday in the area over a short period.

It marked only the third time since earthquake sensors were installed there in 1932 that the area had seen such a swarm, and this one had more earthquakes than the events of 2001 and 2009.

An image provided by Caltech seismologist Egill Hauksson shows the earthquake swarms of 2001, 2009 and 2016 in the Salton Sea. According to the Southern California Seismic Network, more than 35 small earthquakes were recorded Monday in the area over a short period.