More earthquake swarms reported in Yellowstone during October 2013

According to Yellowstone Volcano Observatory monthly update, University of Utah reported 168 earthquakes in the Yellowstone National Park region during October 2013. The largest event was a minor earthquake of magnitude 2.9 on October 30, 2013 at 06:58 UTC, located about 11.2 km (7 miles) north of Lake, WY.

Comparing earthquake activity in October to the previous month, it seems seismicity returned to relatively normal background levels.

October seismicity in Yellowstone was marked by three distinct clusters of episodic earthquakes:

1. A swarm of 54 earthquakes, ~12 km (7.5 miles) north of Old Faithful, WY, occurred on October 5th, the largest earthquake in the swarm (magnitude 2.8) occurred at 15:09 UTC ~12 km north of Old Faithful, WY.
2. A small swarm of 16 earthquakes, ~21 km (13 miles) east-northeast of Island Park, ID took place October 20 – 23, the largest earthquake (magnitude 2.1) occurred October 20th at 08:28 UTC.
3. A small swarm of 15 earthquakes, ~9.6 km (6 miles) north of West Yellowstone, MT occurred October 12, the largest earthquake (magnitude 2.3) occurred at 07:35 UTC.

During September 2013, there were 469 earthquakes reported in the Yellowstone National Park region. The largest event was a minor earthquake of magnitude 3.6 on September 15, 2013 at 16:53 UTC, located about 11.2 km (7 miles) north of Old Faithful, WY.

September seismicity in Yellowstone was marked by five distinct clusters of episodic earthquakes:

1. A notable swarm of 246 earthquakes, ~8km (5 miles) north of Old Faithful, WY, began September 13 and tapered off September 20th, including the largest event of the month on September 15 (magnitude 3.6).
2. 81 events occurred in an episodic swarm ~27.3 km (17 miles) east-northeast of West Yellowstone, MT, with swarm activity occurring September 13 and again from September 24, through September 30. The largest earthquake of the swarm (magnitude 3.5) occurred September 13, at 13:56 UTC~25.7 km (16 miles) south-southwest of Mammoth, WY.
3. A small swarm of 27 earthquakes, ~9.6 km (6 miles) north of West Yellowstone, MT, took place on September 27 and 28, with the largest event (magnitude 2.3) occurring September 27, at 16:40 UTC.
4. A small swarm of 23 earthquakes, ~14.4 km (9 miles) north-northeast of Old Faithful, WY, began September 3 and ended September 5. The largest earthquake (magnitude 2.2) occurred September 4, at 13:10 UTC ~14.4 km north-northeast of Old Faithful, WY.
5. The southernmost September 2013 swarm of 21 earthquakes, ~11.2 km (7 miles) south-southwest of West Thumb, WY, occurred September 10. The largest earthquake (magnitude 3.3) took place in the center of the swarm at 13:46 AM MDT.

Yellowstone earthquake activity in September was at elevated levels during the above swarms but, has returned to a relatively normal background level by October 1, 2013.

Slow subsidence of the caldera, which began in early 2010, continues. Current deformation patterns at Yellowstone remain within historical norms.

Read more: Repeating earthquakes suggest volcanic and tectonic origins of Yellowstone seismic swarms 

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Source: Yellowstone Volcano Observatory – Monthly reports for September and October 2013.

Featured image: YVO – Biscuit Basin webcam – November 3, 2013.