November 10, 2016
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
* On October 21, there was a Magnitude (M) 6.6 earthquake in the central Tottori prefecture. Maximum seismic intensity 6 Lower was observed in Tottori prefecture with some damage.
* On October 12, there was a M5.0 earthquake at a depth of approximately 50 km under the eastern Hidaka region [the southern Tokachi region]. The focal mechanism showed a reverse fault type with a compression axis in an NW-SE direction. This event occurred at the boundary between the Pacific and the continental plates.
* On October 24, there was a M6.0 earthquake at a depth of approximately 40 km (due to CMT solution), offshore east of Hokkaido. The focal mechanism showed a reverse fault type with a compression axis in an NW-SE direction. This event occurred at the boundary between the Pacific and the continental plates.
* On October 16, there was a M5.2 earthquake at a depth of approximately 20 km in the central Miyagi prefecture [off Miyagi prefecture]. The focal mechanism had a compression axis in an NNW-SSE direction. This event occurred within the crust.
* On October 20, there was a M5.3 earthquake at a depth of approximately 35 km under the northeastern Chiba prefecture. The focal mechanism showed a reverse fault type with a compression axis in a WNW-ESE direction. This event occurred at the boundary between the Philippine Sea and the continental plates.
* In the GNSS data for the Tokai region, there has been no change of activity which is likely to be associated with the Tokai earthquake.
* On October 22, there was a M4.4 earthquake at a depth of approximately 55 km under the southern Oita prefecture [Hyuganada]. The focal mechanism had a tension axis in an NW-SE direction. This event occurred within the Philippine Seal plate.
Note:[ ] is the regional name of the epicenter used in the announcement
of Japan Meteorological Agency.
GNSS (Global Navigation Satellite System) is a general name of satellite positioning system such as GPS.
November 10, 2016
Earthquake Research Committee
The following are the numbers of earthquakes by magnitude that occurred in Japan and the surrounding area during October 2016.
(reference)
The following events for the period from October 2015 to late September 2016 have been listed as "Major Seismic Activities" in monthly "Evaluation of Seismic Activities."
| – Offshore West of the Satsuma Peninsula | M7.1 on November 14, 2015 | |
| – Sanpachi-Kamikita Region, Aomori Prefecture | M4.6 on January 11, 2016 (Depth of approximately 10 km) |
|
| – Offshore Urakawa | M6.7 on January 14, 2016 (Depth of approximately 50 km) |
|
| – Kumamoto Earthquakes | M6.5 on April 14, 2016 and M7.3 on April 16, 2016 (Depth of approximately 10 km) |
|
| – Southern Ibaraki Prefecture | M5.5 on May 16, 2016 (Depth of approximately 40 km) |
|
| – Uchiura Bay | M5.3 on June 16, 2016 (Depth of approximately 10 km) |
|
| – Northern Ibaraki Prefecture | M5.4 on July 27, 2016 (Depth of approximately 55 km) |
|
| – Kumamoto Region, Kumamoto Prefecture | M5.2 on August 31, 2016 (Depth of approximately 15 km) |
|
| – Ocean Area near Okinawa Main Island | M5.6 on September 26 (Depth of approximately 45 km) |
There is no supplementary information for Hokkaido region.
There is no supplementary information for Tohoku region.
–"In the GNSS data for the Tokai region, there has been no change
of activity which is likely to be associated with the Tokai earthquake.":
(This evaluation is in agreement with the views presented at the regular meeting on October 18 of the Assessment Committee for Areas under Intensified Measures against Earthquake Disaster (reference below).)
(Reference)
Recent seismic and crustal activity in the Tokai region and its vicinity (Seismological and Volcanological Department, Japan Meteorological Agency, October 18, 2016)
"No change of activity which is likely to be associated with the Tokai earthquake has been observed until now. (Excerpted)"
– Non-stationary crustal deformation surrounding the Kii Channel observed from mid-2014 seems to be generally almost finished. This deformation is thought to be due to a slow slip (slow-slip) at the boundary between the Philippine Sea and the continental plates.
– Non-stationary crustal deformation surrounding the Bungo Channel observed from around December 2015 is now decaying. This deformation is thought to be due to a slow slip (slow-slip) at the boundary between the Philippine Sea and the continental plates.
– In October, no earthquake with maximum seismic intensity 4 (2 in September) and 4 earthquakes with maximum seismic intensity 3 (7 in September) occurred in the Kumamoto and the Aso regions, Kumamoto prefecture. A series of seismic activity of the 2016 Kumamoto Earthquakes in Kumamoto region and Aso region is still continuing, decaying as a whole. According to the GNSS observation, postseismic deformation is still observed in the area centered on the series of the seismic activity.
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: