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| Earth on Dec 07, 2012

Strong 7.3-magnitude earthquake and small tsunami strike northeastern Japan

Same region as powerful 9.0-magnitude earthquake that rocked Japan in March, 2011. No reports of injuries or damages. No risk of a widespread tsunami.

A strong undersea earthquake and several strong aftershocks struck near the northeast coast of Japan – east of Sendai, Japan – Friday (December 7, 2012), in the same region that was hit by a massive 9.0 magnitude earthquake in March, 2011. CBSNews is reporting that a small tsunami hit a small city in the region, but there were no reports of injuries or damage. The Pacific Tsunami Warning Center said there was no risk of a widespread tsunami and has now dropped all tsunami warnings for the Japanese coast. The Japan Meteorological Agency said the epicenter was 6.2 miles beneath the sea floor.

7.3-magnitude earthquake December 8, 2012

Here are the details of the quake, according to the U.S. Geological Survey (USGS):

Event Time
2012-12-07 08:18:24 UTC
2012-12-07 18:18:24 UTC+10:00 at epicenter
2012-12-07 02:18:24 UTC-06:00 system time

Location
37.889°N 144.090°E depth=36.1km (22.4mi)

Nearby Cities
245km (152mi) SE of Kamaishi, Japan
245km (152mi) ESE of Ofunato, Japan
251km (156mi) ESE of Ishinomaki, Japan
251km (156mi) SE of Otsuchi, Japan
462km (287mi) ENE of Tokyo, Japan

A map of Earth’s tectonic plates. Plate boundaries are shown in red. View larger. USGS image via windows2universe.org

The December 7, 2012 7.3-magnitude earthquake, occurred due to movement within faults in the oceanic lithosphere – the crust and the uppermost mantle – of the Pacific plate. It happened approximately 20 km east of the plate boundary between the Pacific and North America plates, in a place where the Pacific plates subducts, or dives beneath, Japan. At the epicenter of this earthquake, the Pacific plate moves west-northwestard with respect to the North America plate at a velocity of approximately 83 millimeters (about 3.3 inches) per year.

Bottom line: The northeast coast of Japan – same area affected by a more powerful 9.0-magnitude earthquake in March, 2011 – underwent a strong undersea earthquake and several strong aftershocks on Friday (December 7, 2012). A small tsunami hit a small city in the region, but there were no reports of injuries or damage. The Pacific Tsunami Warning Center said there was no risk of a widespread tsunami and has now dropped all tsunami warnings for the Japanese coast.