REDLANDS--An active earthquake “swarm” that began February 13th is keeping parts of the Inland Empire on edge.

The shaking has been traced to an epicenter south of Redlands in San Timoteo Canyon.

Triple back-to-back quakes felt just before noon Friday were among the strongest at M3.6. Another M3.0 hit Friday evening.

Seismologist Tom Heaton at Cal Tech described the sequence as ‘not unusual’.

“It’s really difficult to predict what will happen with a swarm. Sometimes they go on for weeks or months. Sometimes they’re over in a couple of days.”

Earthquake ‘swarms’ usually occur in active geothermal areas. This sequence is associated with the San Jacinto Fault and is happening at a depth of three to four miles.

There has been no reported damage. (INT)

Story Date: February 23, 2010