概要

千島海溝付近における海溝型地震で、マグニチュード（モーメントマグニチュード、M）は9.0の超巨大地震である。津波は日本では遡上高8.5mであり、第一波の高さは1.0mであった。約3000km離れたハワイ諸島西端のミッドウェイ島にも襲ってきた。

カムチャッカ半島沖では、1737年にもM9.0 - 9.3の規模と推定される地震が発生している。

ロシア極東カムチャツカ沖でＭ8.2の地震＝ＵＳＧＳ
2013年 05月 24日 15:14 JST
　
［ロンドン　２４日　ロイター］ - 米地質調査所によると、ロシア極東のカムチャツカ半島沖のオホーツク海でマグニチュード（Ｍ）８．２の地震が発生した。

震源はペトロパブロフスクカムチャツキーの西北西２４４マイル、震源の深さは３８５マイル。
　
関連ニュース

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イランでＭ8の大きな地震＝米地質調査所 2013年4月16日

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300 km
200 mi
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54.874°N, 153.281°E
Depth: 608.9km (378.4mi)
Event Time

2013-05-24 05:44:49 UTC
2013-05-24 15:44:49 UTC+10:00 at epicenter
2013-05-24 14:44:49 UTC+09:00 system time
Location

54.874°N 153.280°E depth=608.9km (378.4mi)

Nearby Cities

362km (225mi) WSW of Esso, Russia
383km (238mi) WNW of Yelizovo, Russia
400km (249mi) NW of Vilyuchinsk, Russia
406km (252mi) WNW of Petropavlovsk-Kamchatskiy, Russia
2374km (1475mi) NNE of Tokyo, Japan
Related Links

Additional earthquake information for Russia
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Tectonic Summary

The May 24, 2013 Mw 8.3 earthquake beneath the Sea of Okhotsk, Russia, occurred as a result of normal faulting at a depth of approximately 600 km. At the latitude of this earthquake, the Pacific and North America plates are converging at a rate of approximately 78 mm/yr in a west-northwest – east-southeast direction, resulting in the subduction of the Pacific plate beneath Eurasia at the Kuril-Kamchatka trench. Note that some authors divide this region into several microplates that together define the relative motions between the larger Pacific, North America and Eurasia plates; these include the Okhotsk and Amur microplates that are respectively part of North America and Eurasia. The depth and faulting mechanism of the May 24 earthquake indicate that it ruptured a fault deep within the subducting Pacific lithosphere rather than on the shallow thrust interface between the two plates.

This deep section of the Pacific slab beneath the Sea of Okhotsk has hosted several large earthquakes in the past – four above M 6 within 200 km of the May 24 event since 1988. These included a M 7.7 earthquake in July 2008, 115 km to the southwest at a depth of 630 km, and a M 7.3 event in November of the same year, 95 km to the southeast at a depth of 490 km. Because of their great depths, none are known to have caused damage. Intermediate-depth (70-300 km) and deep-focus (depth > 300 km) earthquakes are distinguished from shallow earthquakes (0-70 km) by the nature of their tectonic setting, and are in general less hazardous than their shallow counterparts, though they may be felt at great distances from their epicenters. The Pacific slab in the region of the May 24 2013 earthquake is seismically active to depths of over 650 km.

Seismotectonics of the Kuril-Kamchatka Arc

The Kuril-Kamchatka arc extends approximately 2,100 km from Hokkaido, Japan, along the Kuril Islands and the Pacific coast of the Kamchatka Peninsula to its intersection with the Aleutian arc near the Commander Islands, Russia. It marks the region where the Pacific plate subducts into the mantle beneath the Okhotsk microplate, part of the larger North America plate. This subduction is responsible for the generation of the Kuril Islands chain, active volcanoes located along the entire arc, and the deep offshore Kuril-Kamchatka trench. Relative to a fixed North America plate, the Pacific plate is moving towards the northwest at a rate that increases from 75 mm/year near the northern end of the arc to 83 mm/year in the south.

Plate motion is predominantly convergent along the Kuril-Kamchatka arc with obliquity increasing towards the southern section of the arc. The subducting Pacific plate is relatively old, particularly adjacent to Kamchatka where its age is greater than 100 Ma. Consequently, the Wadati-Benioff zone is well defined to depths of approximately 650 km. The central section of the arc is comprised of an oceanic island arc system, which differs from the continental arc systems of the northern and southern sections. Oblique convergence in the southern Kuril arc results in the partitioning of stresses into both trench-normal thrust earthquakes and trench-parallel strike-slip earthquakes, and the westward translation of the Kuril forearc. This westward migration of the Kuril forearc currently results in collision between the Kuril arc in the north and the Japan arc in the south, resulting in the deformation and uplift of the Hidaka Mountains in central Hokkaido.

The Kuril-Kamchatka arc is considered one of the most seismically active regions in the world. Deformation of the overriding North America plate generates shallow crustal earthquakes, whereas slip at the subduction zone interface between the Pacific and North America plates generates interplate earthquakes that extend from near the base of the trench to depths of 40 to 60 km. At greater depths, Kuril-Kamchatka arc earthquakes occur within the subducting Pacific plate and can reach depths of approximately 650 km.

This region has frequently experienced large (M>7) earthquakes over the past century. Since 1900, seven great earthquakes (M8.3 or larger) have also occurred along the arc, with mechanisms that include interplate thrust faulting, and intraplate faulting. Damaging tsunamis followed several of the large interplate megathrust earthquakes. These events include the February 3, 1923 M8.4 Kamchatka, the November 6,1958 M8.4 Etorofu, and the September 25, 2003 M8.3 Hokkaido earthquakes. A large M8.5 megathrust earthquake occurred on October 13, 1963 off the coast of Urup, an island along the southern Kuril arc, which generated a large tsunami in the Pacific Ocean and the Sea of Okhotsk, and caused run-up wave heights of up to 4-5 m along the Kuril arc. The largest megathrust earthquake to occur along the entire Kurile-Kamchatka arc in the 20th century was the November 4, 1952 M9.0 event. This earthquake was followed by a devastating tsunami with run-up wave heights as high as 12 m along the coast of Paramushir, a small island immediately south of Kamchatka, causing significant damage to the city of Severo-Kurilsk.

On October 4,1994, a large (M8.3) intraplate event occurred within the subducted oceanic lithosphere off the coast of Shikotan Island causing intense ground shaking, landslides, and a tsunami with run-up heights of up to 10 m on the island.

The most recent megathrust earthquake in the region was the November 15, 2006 M8.3 Kuril Island event, located in the central section of the arc. Prior to this rupture, this part of the subduction zone had been recognized as a seismic gap spanning from the northeastern end of the 1963 rupture zone to the southwestern end of the 1952 rupture. Two months after the 2006 event, a great (M8.1) normal faulting earthquake occurred on January 13, 2007 in the adjacent outer rise region of the Pacific plate. It has been suggested that the 2007 event may have been caused by the stresses generated from the 2006 earthquake.

More information on regional seismicity and tectonics

CNN.co.jp 5月24日(金)17時6分配信

（ＣＮＮ）　ロシアのカムチャツカ半島沖で２４日、マグニチュード（Ｍ）８．２の地震が発生した。米地質調査所（ＵＳＧＳ）が発表した。

震源はカムチャツカ半島西のオホーツク海で、深さ約６００キロ。

ロシアのノーボスチ通信によると、約５分間の強い揺れが発生し、多くの人が通りに逃げ出たという。

現在のところ、津波警報は出ていない。

http://headlines.yahoo.co.jp/hl?a=20130524-35032515-cnn-int

これ以上大きいものが来る確率は低そうだが、余震は続いているし、防災体制も怪しいので現地では、まだ暫くは大変だろう