What’s with the earthquake swarm happening near the valley?

An area just northeast of the Coachella Valley has been shaking, rattling and rolling for more than a week.

Check out this database of recent earthquakes in the area, courtesy of the Southern California Earthquake Center — notice a recurring theme? More than 40 small quakes have erupted in the past week in an area about 4 to 11 miles northeast of Indio. Most are in the magnitude 1 to 2 range, but the quakes reached a magnitude 3.5 on April 3 and a magnitude 3.0 last Thursday. They are near but not on the San Andreas fault.

Why is the quake swarm happening? We here on the iSun team go to the experts. And one of the best onĀ  California earthquakes is Caltech seismologist Kate Hutton.

California has swarms like this fairly frequently,” Hutton said in an e-mail. “This is not a volcanic area, so I doubt if it is a dike intrusion.”

That’s a process where magma, molten minerals from deep beneath the earth’s surface, shoots up into or laterally within the earth’s upper crust.

“Most swarms are thought to be related to ground water present in the fault zone,” Hutton said.

As is always the case with earthquakes, there is a small chance they are foreshocks of a much bigger quake to come, she said. “Unfortunately, there is no way at present to tell which ones,” she said.