With more than 20 earthquakes in several hours Saturday evening, and 400 in the past week, Nevada Seismological Laboratory members have mobilized from the University to the Hawthorne area to step-up monitoring efforts for the region. The highest in the sequence occurred at 5:45 p.m. on Sat., April 16. It was a magnitude 4.6, followed 10 minutes later by a 4.1. “Although the earthquake rate has waxed and waned through time, the number of recorded events is very high,” Graham Kent, director of the seismological lab at the University of Nevada, Reno said. In total, this sequence has thus far produced nine magnitude 4 or larger earthquakes near Hawthorne, and about 25 earthquakes larger than magnitude 3.0. A handful of earthquakes were also detected in this area in mid-March, including a magnitude 3.2 on March 15. When compared to the Mogul-Somerset sequence in Reno, Nev. in spring of 2008, rates of magnitude 3 and 4 earthquakes are much higher for the Hawthorne event. For example, throughout 2008 only four magnitude 4 events, including the largest earthquake magnitude 4.7, were registered. A total of 44 magnitude 3.0 or larger earthquakes were seen across all of 2008 in Mogul-Somerset, whereas the Hawthorne swarm has achieved over half this amount in less than one week, and nearly double the number of larger, magnitude 4-plus events.