Tuesday, September 29, 2009

8.0 Earthquake near Samoa

A heads up to GeoTripper for pointing this out earlier today. A magnitude 8.0 earthquake rocked the region around American Samoa today, with an epicenter just 135 miles from mainland Samoa.

Originally, tsunami warnings were issued as far away as Hawaii. NOAA has since canceled these warnings, as Pago Pago, located in Samoa, only experienced waves with a maximum amplitude of 1.57m and a period (frequency) of 4 minutes. (Source, NOAA)

The Tonga Trench, located just west of the earthquake center, has been a very active tectonic region - with the Pacific Plate moving underneath the Australian Plate at a rate of 86 mm/year. Currently, the USGS believes that a normal fault occurred here, near the outer rise of the Pacific Plate. (Source, USGS)

If you want to check out the location of the quake, drop the coordinates "15.558°S, 172.073°W" into Google Earth and check out the proximity to Pago Pago and Samoa, as well as the beautiful images of the trench just to the west of the epicenter. No wonder there was a seismic event here.

Update: Tsunamis were reported in Pago Pago, contrary to the data I received from NOAA. According to CNN, a 3m tsunami hit just after the earthquake.

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