M7.3 - 245km SE of Kamaishi, Japan - 地球科學討論

Event Time

2012-12-07 08:18:24 UTC
2012-12-07 18:18:24 UTC+10:00 at epicenter
2012-12-07 17:18:24 UTC+09:00 system time

Location

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

Nearby Cities

245km (152mi) SE of Kamaishi, Japan (釜石)
245km (152mi) ESE of Ofunato, Japan (大船渡)
251km (156mi) ESE of Ishinomaki, Japan (石巻)
251km (156mi) SE of Otsuchi, Japan (大槌)
462km (287mi) ENE of Tokyo, Japan　

Related Links

Additional earthquake information for Japan
View location in Google Maps

Tectonic Summary
Seismotectonics of Japan and Vicinity

Japan and the surrounding islands straddle four major tectonic plates:
Pacific plate; North America plate; Eurasia plate; and Philippine Sea plate.
The Pacific plate is subducted into the mantle, beneath Hokkaido and northern
Honshu, along the eastern margin of the Okhotsk microplate, a proposed
subdivision of the North America plate. Farther south, the Pacific plate is
subducted beneath volcanic islands along the eastern margin of the Philippine
Sea plate. This 2,200 km-long zone of subduction of the Pacific plate is
responsible for the creation of the deep offshore Ogasawara and Japan
trenches as well as parallel chains of islands and volcanoes, typical of
Circumpacific island arcs. Similarly, the Philippine Sea plate is itself
subducting under the Eurasia plate along a zone, extending from Taiwan to
southern Honshu that comprises the Ryukyu Islands and the Nansei-Shoto trench.

Subduction zones at the Japanese island arcs are geologically complex and
produce numerous earthquakes from multiple sources. Deformation of the
overriding plates generates shallow crustal earthquakes, whereas slip at the
interface of the plates generates interplate earthquakes that extend from
near the base of the trench to depths of 40 to 60 km. At greater depths,
Japanese arc earthquakes occur within the subducting Pacific and Philippine
Sea plates and can reach depths of nearly 700 km. Since 1900, three great
earthquakes occurred off Japan and three north of Hokkaido. They are the M8.4
1933 Sanriku-oki earthquake, the M8.3 2003 Tokachi-oki earthquake, the M9.0
2011 Tohoku earthquake, the M8.4 1958 Etorofu earthquake, the M8.5 1963 Kuril
earthquake, and the M8.3 1994 Shikotan earthquake.

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NHK已改播地震相關新聞, 日本氣象廳亦對宮城縣發布高度兩公尺的海嘯警報, 本州島
其它太平洋沿岸縣份 (青森縣~茨城縣)發布50公分的海嘯注意報

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