December 8, 2008
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
There was no remarkable activity. to supplementary reports
* On November 22, there was a M5.2 earthquake at a depth of approximately 45 km off-shore southeast of the Nemuro Peninsula. The focal mechanism showed a reverse fault with a compression axis in a NNW-SSE direction. This event occurred at the boundary between the Pacific and the continental plates. to supplementary reports
There was no remarkable activity. to supplementary reports
* On November 24, there was a M3.9 earthquake at a depth of approximately 10km in eastern Mino, Gifu prefecture. The focal mechanism showed a reverse fault with a compression axis in an E-W direction. This event occurred within the crust.
* 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
There was no remarkable activity. to supplementary reports
* On December 4, at 08:16 (JST) there was a M6.1 earthquake off-shore of Sanriku. Also at 12:10 on the same day, a M5.5 earthquake occurred. The focal mechanisms for both events showed reverse faults with compression axes in a WNW-ESE direction. The events occurred at the boundary between the Pacific and the continental plates.
* On December 7, there was a M4.4 (preliminary) earthquake at a depth of approximately 10km in central Miyagi prefecture.
December 8, 2008
The following are the numbers of earthquakes by magnitude that occurred in Japan and the surrounding area during November 2008.
(reference)
The following regions have been noted as having major seismic activity during the period from November 2007 to the end of October 2008.
| - Noto region, Ishikawa prefecture | M4.8 on January 26, 2008 (depth approximately 10km) | |
| - Off-shore of Ibaraki prefecture | M7.0 on May 8, 2008 | |
| - Iwate-Miyagi Nairiku Earthquake in 2008 | M7.2 on June 14, 2008 (depth approximately 10km) | |
| - Off-shore of Ibaraki prefecture | M5.2 on July 5, 2008 (depth approximately 50km) | |
| - Near Okinoerabujima | M6.1 on July 8, 2008 (depth approximately 45km) | |
| - Off-shore of Fukushima prefecture | M6.9 on July 19, 2008 | |
| - Central Iwate prefecture | M6.8 on July 24, 2008 (depth approximately 110km) |
|
| - Off-shore of Tokachi | M7.1 on September 11, 2008 |
There is no supplementary information for the Hokkaido region.
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 November 21 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, November 21, 2008)
"So far, there have been no changes of activity which are likely to be associated with the so-called Tokai earthquake.
1. Status of seismicity
There was no remarkable seismic activity in general.
There are continued less frequent occurrences of events equal to or larger than M3.5 within the Philippine Sea plate under mid-western Shizuoka prefecture, and also there are fewer events within the Philippine Sea plate under the region around Hamana lake. On the other hand, there is continued slightly strong seismicity within the crust in Aichi prefecture, and also seismicity has been slightly strong within the crust in mid-western Shizuoka prefecture. In other regions, seismic activity is generally at a normal level.
In addition, during the period from November 10 through 18, there were deep low-frequency earthquakes observed in the area from Ise Bay through Mie and Nara prefectures, which is adjacent to the Tokai region. In this vicinity, deep low-frequency earthquakes were also observed in March and June this year.
2. Status of crustal movements
There were no notable changes observed in general.
According to the GPS data and leveling results, the trend of long-term subsidence at Omaezaki has been continuing as before.
In addition, during the same period of the deep low-frequency seismic activity mentioned above, there were crustal movements observed on strainmeters in the neighboring region, which were thought to be caused by the short-term slow slip in the area around the plate boundary. A similar phenomenon was seen in this vicinity in March and June this year."
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: