Earthquake in Riverside County Sunday Comes Amid Swarm of Small Quakes

(KNX 1070) - There has been a swarm of small earthquakes this weekend in the Inland Empire -- and more continue Monday morning.

A tremblor, measuring at 3.3, hit the Riverside County area Sunday afternoon in the Glen Avon area, south of Fontana in the afternoon.  

However, analysts say that does not mean the Big One is on its way. 

Since midnight, more than two dozen quakes measuring 1.8 or less have hit the area. 

Robert Sanders,  a geophysicist with the US Geological Survey's National Earthquake Information Center, says "forms of this nature are relatively common."

"The big concern people always have is this a precursor to a larger event and we don't have any real, scientific basis to predict earthquakes," he said.

Historically, he says swarms like what we've seen in Riverside County, do not result in a significantly larger earthquake.

That said, it's been nearly five  years since the state has had a quake of magnitude 6 or larger – and 25 years since the 6.7 in Northridge.

It's a good reminder to be prepared.

A swarm of hundreds of small earthquakes has kept parts of the Inland Empire shaking. The largest quake (magnitude 3.3) struck Sunday afternoon, but analysts say that does NOT mean the BIG ONE is immediately imminent. More @KNX1070 https://t.co/BHH27v8Btt

Seismologists are trying to calm nerves since the earth has been moving in the Inland Empire and the shaking continuing Monday morning after hundreds of small quakes.

The Fontana quakes are very small - only a few are even above M2.5, none above M3. They are being felt because they are so shallow. When the quake is only 1 mile down, instead of 5 miles or more, you are that much closer to the event. #earthquakeswarm