After two moderate quakes on Wednesday night, the most recent Yellowstone National Park earthquake swarm appears to be shifting, with more quakes recorded on Thursday and Friday morning, but most of the small were of a very minor magnitude.

From the University of Utah Seismograph Station:

These two earthquakes are part of an ongoing swarm in Yellowstone National Park that began January 17, 2010 (1:00 PM MST). The largest earthquake in the swarm as of 12 PM, January 21, 2010, was a magnitude 3.8. There have been 901 located earthquakes in the swarm of magnitude 0.5 to 3.8. This includes 8 events of magnitude larger than 3, with 68 events of magnitude 2 to 3, and 825 events of magnitude less than 2. There have been multiple personal reports of ground shaking from observations inside the Park and in surrounding areas for some of the larger events (for felt reports, please visit http://earthquake.usgs.gov/eqcenter/dyfi/). Earthquake swarms are relatively common in Yellowstone.

The consensus in the scientific community: the swarm of earthquakes is caused by tectonic shifts, not anything to do with the Yellowstone caldera. These same shifts are causing more severe earthquakes in areas like Haiti and Oklahoma. Other monitoring stations indicate no change at all in activity with the caldera and the Yellowstone supervolcano.

You can view a map chronicling recent seismic activity here.

Almost 80 swarms have been recorded in Yellowstone since 1995. 

RELATED STORIES: Earthquake Swarm Continues in Yellowstone; Small Earthquake Swarm Hits Yellowstone; Is Yellowstone Caldera Stabilizing? Recent Seismic Evidence Says Yes

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