According to the USGS, earthquake swarms have been known to last up to 20 days. But they typically last from 7 to 10 days.
Earthquake activity measured
On Thursday Caltech and the USGS published a report specific to the Westmorland earthquake swarm.
They measured the earthquakes’ intensities and found that the smallest magnitude was 1.1, and the highest was 4.9. Most of the tremors were below 3.0 magnitude, but several earthquakes registered over 4.5 magnitudes.
Magnitude measures energy released at the epicenter or source of the earthquake, the U.S. Geological Survey explained. It is more accurate than the old Richter scale measurements.
The impacted area can be viewed on an interactive map.
Seismologist, Dr. Lucy Jones said that more than 45 earthquakes took place in the area within a two and a half-hour period on Wednesday. Jones described the shaking phenomenon as “one of the largest swarms we have had in the Imperial Valley.”
The Imperial Valley has been identified as one of the most active seismic regions in California. The USGS reported on Friday that a dozen quakes hit the area since midnight.
