The Alaska Earthquake Centre recorded
a Magnitude 5.2 Earthquake at a depth of 70 km, about 42 km to the west of Willow, Alaska, slightly before 4.10 pm local time on Monday 16 September 2019 (slightly
before 1.10 am on Tuesday 17 September GMT). There are
no reports of any damage or
casualties associated with this event, but people have
reported feeling it over a wide area of southeast Alaska, .
Alaska
lies on the North American Plate, with the Pacific Plate underlying the
ocean to the south. The Aleutian Trench runs along much of the south
coast of Alaska, with the Pacific Plate being subducted beneath this and
passing under Alaska as it sinks into the Earth. Off the coast of southeast Alaska the Pacific and North
American Plates pass one-another horizontally, with the Pacific Plate
moving northward and the North American to the south (a transform plate
margin). This is not a smooth process, and the plates frequently stick
together, then break apart as the pressure builds up, causing
Earthquakes.
Model of the subduction of the Pacific Plat beneath the North
American Plate along the southern coast of Alaska and the Aleutians. USGS.
Witness
accounts of quakes can help geologists to understand these events and
the rock structures that cause them. If you felt this quake (or if you
were in the area but did not, which is also useful information) you can
report it to the United States Geological Survey here.
See also...
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