July 12, 2006 Headquarters for Earthquake Research Promotion Earthquake Research Committee

	- Amakusa Ashikita region,                       Kumamoto prefecture	M4.8 on June 3, 2005 (depth approximately 10km)
	- Chuetsu region, Niigata prefecture	M5.0 on June 20, 2005 (depth approximately 15km)
	- Northwestern Chiba prefecture	M6.0 on July 23, 2005 (depth approximately 75km)
	- Off-shore of Miyagi prefecture	M7.2 on August 16, 2005 (depth approximately 40km)
	- Chuetsu region, Niigata prefecture	M5.0 on August 21, 2005 (depth approximately 15km)
	- Off-shore of Ibaraki prefecture	M6.3 on October 19, 2005 (depth approximately 50km)
	- Off-shore of Sanriku	M7.2 on November 15, 2005
	- Hyuganada	M5.5 on March 27, 2006 (depth approximately 35km)
	- Off-shore east of the Izu Peninsula	seismic activity with M5.8 on April 21 and M4.5 on April 30, 2006

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2 Nationwide Seismic Activity by Region

(1) Hokkaido Region

There is no supplementary information for the Hokkaido region.

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(2) Tohoku Region

- On June 17, there were M5.7 and M5.6 events off-shore of Sanriku. Both focal mechanisms showed reverse faults with compression axes in a WNW-ESE direction.

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(3) Kanto-Chubu Region

"The long-term changes that have been observed since 2001 in the continuous GPS data in the Tokai region, appear to have nearly stopped recently.":
According to the GPS data, the Pacific side of the Tokai-Chubu region maintained a steady rate with movement to the WNW, consistent with the subduction of the Philippine Sea plate toward the northwest. The results, from observations in the area centered on western Shizuoka prefecture, have been showing a trend of moderate change since about April 2001. This long-term changes seem to have nearly stopped recently.
(This evaluation is in agreement with the views presented at the procedural meeting on June 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" (Japan Meteorological Agency, Department of Seismology and Volcanology, June 26, 2006)

"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. The seismicity continues at a level lower than normal directly under the area from eastern Hamana lake through central Shizuoka prefecture. In other regions, seismic activity is generally at a normal level.
The long-term crustal movements from the slow slip at the plate boundary in the Tokai region and its neighboring area, seem to have nearly stopped recently."

There was additional activity in the Kanto - Chubu region, as follows.
- On June 24, there was a M3.9 earthquake at a depth of approximately 10km near the border between Nagano and Gifu prefectures [in southern Nagano prefecture] (maximum seismic intensity 4).


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(4) Kinki-Chugoku-Shikoku Region

There is no supplementary information for the Kinki - Chugoku - Shikoku region.

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(5) Kyushu-Okinawa Region

There is no supplementary information for the Kyushu - Okinawa region.

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Supplement

"On July 1, there was a M5.3 earthquake at a depth of approximately 40km off-shore of Miyagi prefecture. 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 near the northern edge of the aftershock region of the earthquake off-shore Miyagi prefecture on August 16, 2005 (M7.2). In this vicinity, there was a M6.1 earthquake on December 17, 2005.

- On July 9, there was a M4.2 earthquake at a depth of approximately 25km under Tokyo Bay (maximum seismic intensity 3).
- On July 9, there was a M4.8 earthquake at a depth of approximately 10km under the ocean area near Niijima and Kozushima Islands (maximum seismic intensity 4).

[ ] was the regional name of the epicenter used in the Japan Meteorological Agency announcement.

Reference 1 Earthquakes that are described in the "Evaluation of Seismic Activity"(Monthly Report of Seismic Activity in Japan) are events of M6.0 and greater, or events of M4.0 and greater (M5.0 or greater off-shore) that have maximum intensity of 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.