Thursday 27 June 2013

Magnitude 4.3 Earthquake in central Washington State.

A Magnitude 4.3 Earthquake occurred in central Washington State at around 7.45 pm on Wednesday 26 June 2013 local time (2.45 am on Thursday 27 June, GMT), according to the United States Geological Survey. The quake happened roughly 120 km east of Seattle at a depth of 9.1 km, and was felt across much of the State, though there have not been any reports of any serious damage or injuries. 

The location of the 26 June 2013 Washington Earthquake. Google Maps.

Washington State is located on the western margin of the North American Plate, to the west the Juan de Fuca Plate is being subducted along the Cascadia Subduction Zone, passing under Washington State as it sinks into the Earth. This is not a smooth process, and the two plates frequently stick together then break apart again as the pressure builds up, causing Earthquakes in the process. 

The heat and pressure within the Earth also slowly melts the subducting plate, liquifying more volatile minerals which then rise through the overlying North American Plate as magma, fueling the volcanoes of America's Pacific Northwest.

The subduction of the Juan de Fuca Plate beneath Washington State. University of Florida.

Witness accounts of quakes can help geologists to understand these events and the rock structures that cause them. If you felt this quake you can report it to the USGS here.

Follow Sciency Thoughts on Facebook.