February 9, 2009
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
There was no remarkable activity. to supplementary reports
* On January 11, there was a M4.7 earthquake at a depth of approximately 70km under central Tokachi subprefecture [under southern Tokachi subprefecture]. The focal mechanism had a tension axis in a NNE-SSW direction. It is thought that this event occurred within the Pacific plate. to supplementary reports
* On January 3, there was a M4.8 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 at the boundary between the Pacific and the continental plates. to supplementary reports
* 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 January 24, there was a M5.1 earthquake under the ocean area near Miyakojima. to supplementary reports
* On January 4, at 04:43 (JST) there was a M7.6 earthquake near New Guinea. Tsunamis were observed on the Izu and Ogasawara Islands, Nansei Islands and the Pacific coast from the Kanto region through the Kyushu region. There were tsunami heights of 0.4m on Chichijima and in Kushimoto-cho, Wakayama prefecture. Also at 07:33 (JST) on the same day, there was a M7.4 event at nearly the same location.
* On January 16, there was a M7.4 earthquake off-shore east of the Chishima Islands [off-shore of the Chishima Islands]. Associated with this event, small tsunamis were observed on Chichijima. The focal mechanism showed a reverse fault with a compression axis in a WNW-ESE direction. It is thought that this event occurred within the Pacific plate. to supplementary reports
* On February 1, there was a M5.8 earthquake at a depth of approximately 45km 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.
[ ] were the regional names of the epicenters used in the Japan Meteorological Agency announcement.
February 9, 2009
The following are the numbers of earthquakes by magnitude that occurred in Japan and the surrounding area during January 2009.
(reference)
The following regions have been noted as having major seismic activity during the period from January 2008 to the end of December 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 January 26 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" (Seismological and Volcanological Department, Japan Meteorological Agency, January 26, 2009)
"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. However, when considering smaller events as well, seismic activity has been continuing to be at a high level. Also, there are continued fewer events within the Philippine Sea plate under the region around Hamana lake. On the other hand, seismicity has been continuing to be strong within the crust in mid-western Shizuoka prefecture. In other regions, seismic activity is generally at a normal level.
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."
There is no supplementary information for the Kinki-Chugoku-Shikoku region.
There is no supplementary information for the Kyushu-Okinawa region.
"On January 16, there was a M7.4 earthquake off-shore east of the Chishima Islands [off-shore of the Chishima Islands]. (excerpted).":
In this vicinity, there was a M7.9 earthquake on November 15, 2006, and a M8.2 on January 13, 2007.
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: