|
October 10, 2007 |
| * | There was no remarkable activity. to supplementary reports |
| * | On September 4, there was a M6.3 earthquake at a depth of approximately 130km under the Chishima Islands. The focal mechanism had a compression axis in a WNW-ESE direction. This event occurred within the Pacific plate. to supplementary reports | |
| * | There was no remarkable activity. to supplementary reports |
| * | Using Synthetic Aperture Radar data (SAR) from the advanced land observing satellite, "Daichi", in the area near the Oginojo anticline on the western slope of the Nishiyama Hills located to the east of the focal region of the Niigataken Chuetsu-oki Earthquake in 2007, an uplift zone of approximately 15km in length and 1.5km in width was observed, which is associated with the earthquake. An approximately 10cm or more of maximum uplift was seen, which is consistent with leveling results. According to the GPS data, postseismic movements have been continuing in the area near the focal region of the Niigataken Chuetsu-oki Earthquake in 2007. |
| * | 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 September 22, there was a M5.1 earthquake under the ocean area near Miyakojima. | |
| * | On September 7, there was a M6.6 earthquake near Taiwan. The focal mechanism showed a reverse fault with a compression axis in an E-W direction. to supplementary reports | |
| * | On September 28, there was a M7.4 (moment magnitude by USGS) earthquake at a depth of approximately 260km under the Mariana Islands. The focal mechanism had a tension axis in the direction of the subducting plate. This event occurred within the Pacific plate. |
| * | On October 1, there was a M4.9 earthquake at a depth of approximately 15km in western Kanagawa prefecture. The focal mechanism had a compression axis in a NNW-SSE direction. This event is related to the subducting Philippine Sea plate. |
| * | On October 9, there was a M5.8 earthquake off-shore east of Hokkaido. |
[ ] were the regional names of the epicenters used in the Japan Meteorological Agency announcement.
October 10, 2007
The following are the numbers of earthquakes by magnitude that occurred in Japan and the surrounding area during September 2007.
| M4.0 or greater: 59 (125 events occurred in August) | |
| M5.0 or greater: 7 (21 events occurred in August) | |
| M6.0 or greater: 3 (There has been a total of 20 events for 2007 by the end of September.) |
(reference)
| M4.0 or greater: 73 / month | (Median number of earthquakes over the past 10 years from 1996 through 2005) | |
| M5.0 or greater: 9 / month | (Median number of earthquakes over the past 30 years from 1976 through 2005) | |
| M6.0 or greater: 1.4 / month, approximately 17 / year | (Average number of earthquakes over the past 80 years from 1926 through 2005) |
The following regions have been noted as having significant seismic activity during the period from September 2006 to the end of August 2007.
| - Off-shore east of the Chishima Islands | M7.9 on November 15, 2006 | |
| - Off-shore east of the Chishima Islands | M8.2 on January 13, 2007 | |
| - 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 |
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 September 25 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, September 25, 2007)
"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, 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."
At a depth of approximately 10km under northern Osaka prefecture, there was a M3.7 earthquake on September 5, and a M3.5 earthquake on September 21. Focal mechanisms of both events showed strike-slip faults with compression axes in an E-W direction. Those events occurred within the crust.
There is no supplementary information for the Kyushu-Okinawa region.
to the text
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Reference 1 Earthquakes that are described in the "Evaluation of Seismic Activity" (Monthly Report of Seismic Activity in Japan) have the following features. 1) Events of M6.0 and greater, or events that have maximum seismic intensity 4 or greater 2) Onshore events of M4.5 and greater that have maximum seismic intensity 3 or greater 3) Events under the ocean areas of M5.0 or greater that have maximum seismic intensity 3 or greater |
|
| Reference 2 Information that is described in the "Supplementary Information to the Evaluation" includes: |
|
| 1) | Reference information related to seismic activity described in the "Evaluation of Seismic Activity" |
| 2) | Recent earthquake activity over the past year related to the events described in "Major Seismic Activity" in the "Evaluation of Seismic Activity" |
| 3) | Seismic activity that has been evaluated, but not included in the "Evaluation of Seismic Activity" because it is within normal bounds and not prominent |