Friday, December 7, 2012

7.3M quake strikes off Japan, raising risk of tsunami - CNN 

 Patterns are Emergent.

Stay Alert.

Will Keep this Blog Updated on Developments.

UPDATE:  Tsunami Warning Cancelled.  Wave estimated 2-5 Feet.  7.12.2012 4:45 CST



Major quake strikes off Japan, raising risk of tsunami

By Jethro Mullen, CNN
updated 4:17 AM EST, Fri December 7, 2012
  • A tsunami warning has been issued for the northeast prefecture of Miyagi
  • But there is no threat of a widespread tsunami in the Pacific, a warning center says
  • The 7.3-magnitude quake shook buildings in Tokyo
(CNN) -- A powerful earthquake struck off the northeast coast of Japan on Friday evening, rattling buildings in Tokyo and raising the risk of a tsunami.
The 7.3-magnitude quake hit 492 kilometers (306 miles) east-northeast of Tokyo, the U.S. Geological Survey said.
The Japan Meteorological Agency warned a tsunami as high as two meters could hit the country's northeast coast following the quake, which struck out at sea.
The agency issued the warning for Miyagi Prefecture, the hardest hit area by the devastating earthquake and tsunami that struck in March 2011.
But the quake Friday hasn't created a widespread threat of a tsunami in the Pacific, according to the Pacific Tsunami Warning Center.



M7.3 - 245km SE of Kamaishi, Japan 2012-12-07 08:18:24 UTC


Location and Magnitude contributed by: USGS, NEIC, Golden, Colorado (and predecessors)


20 km
20 mi
Powered by Leaflet
37.889°N, 144.090°E
Depth: 36.1km (22.4mi)

Event Time

  1. 2012-12-07 08:18:24 UTC
  2. 2012-12-07 18:18:24 UTC+10:00 at epicenter
  3. 2012-12-07 02:18:24 UTC-06:00 system time


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

Nearby Cities

  1. 245km (152mi) SE of Kamaishi, Japan
  2. 245km (152mi) ESE of Ofunato, Japan
  3. 251km (156mi) ESE of Ishinomaki, Japan
  4. 251km (156mi) SE of Otsuchi, Japan
  5. 462km (287mi) ENE of Tokyo, Japan

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.

Kamaishi engulfed by tsunami after earthquake rocks Japan - video ... › ... › Japan disaster
Mar 11, 2011
A devastating six-metre-high tsunami sweeps into the port city of Kamaishi in north-east Japan.