Monday 9 December 2013

Magnitude 4.2 Earthquake in Lincoln County, Wyoming.

The United States Geological Survey recorded a Magnitude 4.2 Earthquake at a depth of 5.0 km in the northeast of Lincoln County, Wyoming, slightly before 11.10 am local time (slightly before 6.10 pm GMT) on Sunday 8 December 2013. The quake was felt across a wide area of west-central Wyoming, though there are no reports of any damage or casualties.

The approximate location of the 8 December 2013 Lincoln County Earthquake. Google Maps.

Wyoming typically suffers two or three moderate sized Earthquakes per year, though quakes large enough to cause significant damage are rare. The mountainous areas of the west of the state have a number of deeply buried faults where occasional movement occurs. This can be caused by movement around the Yellowstone Magma Chamber in the northeast of the state, an area that suffers more-or-less constant small tremors due to the movement of magma beneath the surface, but which seldom experiences larger quakes. The constant small movements around Yellowstone can lead to stress building up in rocks further away, leading to Earthquakes as the rocks release the strain by readjusting their positions, which can affect Wyoming as well as neighbouring Idaho and Montana. The same faults also suffer stress due to more distant rock movements, notably on the subduction zone on the American west coast.

Witness accounts of Earthquakes can help geologists to understand these events and the underlying structures that cause them. If you felt this quake (or if you were in the area but did not, which is also useful information) then you can report it to the United States Geological Survey here.

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