April 11, 2008
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
* There was no remarkable activity. to supplementary reports
*On March 13, there was a M5.3 earthquake at a depth of approximately 60km off-shore southeast of the Nemuro Peninsula. The focal mechanism showed a reverse fault with a compression axis in a NW-SE direction. This event occurred within the Pacific plate. to supplementary reports
*On March 24, there was a M5.3 earthquake at a depth of approximately 50km off-shore of Fukushima prefecture. The focal mechanism showed a reverse fault with a compression axis in a WNW-ESE direction. This event occurred near the boundary between the Pacific and the continental plates. to supplementary reports
*On March 8, there was a M5.2 earthquake at a depth of approximately 55km under northern Ibaraki prefecture [off-shore of Ibaraki prefecture]. The focal mechanism showed a reverse fault with a compression axis in a WNW-ESE direction. This event occurred at the boundary between the Pacific and the continental plates.
*On March 15, there was a M6.6 earthquake under the ocean area near Chichijima. The focal mechanism showed a reverse fault with a compression axis in a WNW-ESE direction.
*There have been no anomalous changes observed in the GPS data for the Tokai region. to supplementary reports
* There was no remarkable activity. to supplementary reports
*On March 10, there was a M5.1 earthquake at a depth of approximately 30km in Hyuganada. The focal mechanism showed a reverse fault with a compression axis in a WNW-ESE direction. This event occurred at the boundary between the Philippine Sea and the continental plates. to supplementary reports
*On March 3, there was a M6.9 earthquake off-shore east of the Chishima Islands. The focal mechanism showed a reverse fault with a compression axis in a NW-SE direction. This event occurred at the boundary between the Pacific and the continental plates. This event occurred within the aftershock area of the M7.9 earthquake on November 15, 2006.
*On April 4, there was a M5.0 earthquake at a depth of approximately 55km under southern Ibaraki prefecture. The focal mechanism had a tension axis in an E-W direction. This event is related to the subduction of the Philippine Sea plate.
[ ] was the regional name of the epicenter used in the Japan Meteorological Agency announcement.
April 11, 2008
The following are the numbers of earthquakes by magnitude that occurred in Japan and the surrounding area during March 2008.
(reference)
The following regions have been noted as having major seismic activity during the period from March 2007 to the end of February 2008.
| - Noto Hanto Earthquake | M6.9 on March 25, 2007 (depth approximately 10km) | |
| - Central Mie prefecture | M5.4 on April 15, 2007 (depth approximately 15km) | |
| - Off-shore northwest of Miyakojima | seismic activity with M6.3, M6.7 and M6.1 on April 20, 2007 | |
| - Niigataken Chuetsu-oki Earthquake in 2007 | M6.8 on July 16, 2007 (depth approximately 10km) | |
| - Off-shore west of Sakhalin | M6.4 on August 2, 2007 | |
| - Near the coastal area of Kujukurihama | seismic activity with M5.3 on August 16, and M4.8 on August 18, 2007 | |
| - Coast of Peru | M8.0 on August 16, 2007 | |
| - Western Kanagawa prefecture | M4.9 on October 1, 2007 (depth approximately 15km) | |
| - Noto region, Ishikawa prefecture | M4.8 on January 26, 2008 (depth approximately 10km) |
"On March 13, there was a M5.3 earthquake at a depth of approximately 60km off-shore southeast of the Nemuro Peninsula. The focal mechanism showed a reverse fault with a compression axis in a NW-SE direction. This event occurred within the Pacific plate.":
This event is located near the southwestern edge of the aftershock area of the 1994 Off-shore East Hokkaido Earthquake (M8.2). There was a M7.0 earthquake at the nearly same location on January 28, 2000.
There is no supplementary information for the Tohoku region.
"There have been no anomalous changes observed in the GPS data for the Tokai region.":
(This evaluation is in agreement with the views presented at the procedural meeting on March 24 of the Assessment Committee for Areas under Intensified Measures against Earthquake Disaster. (see reference below))
(reference)
"Recent seismic and crustal activity in the Tokai region and its vicinity" (Japan Meteorological Agency, Department of Seismology and Volcanology, March 24, 2008)
"So far, there have been no changes of activity which are likely to be associated with the so-called Tokai earthquake.
There was no remarkable seismic activity in general. Under central Shizuoka prefecture, the seismicity remains at a level lower than normal within the plate, and higher within the crust. In other regions, seismic activity is generally at a normal level.
There were no notable changes observed in crustal movements in the Tokai region and its neighboring areas."
- Light seismicity, with the largest earthquake a M4.5 event on March 17, has been occurring on the western edge of the aftershock area of the Noto Hanto Earthquake in 2007, since late February.
- According to the GPS data, small crustal movements were observed in the area near Chichijima associated with the M6.6 earthquake that occurred under the ocean near Chichijima on February 27.
There is no supplementary information for the Kinki-Chugoku-Shikoku region.
There is no supplementary information for the Kyushu-Okinawa region.
Reference 1
Earthquakes that are described in the "Evaluation of Seismic Activity" (Monthly Report of Seismic Activity in Japan) have the following features.
Reference 2
Information that is described in the "Supplementary Information to the Evaluation" includes: