November 10, 2017
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
* On October 6, there was a magnitude (M) 5.9 earthquake offshore Fukushima prefecture. Maximum seismic intensity 5 Lower was observed in Fukushima prefecture and was caused damage with injured persons and so on.
There was no remarkable activity.
* On October 6, there was an M6.3 earthquake at a depth of approximately 10 km (CMT solution), offshore Fukushima prefecture. The focal mechanism showed a normal fault type with a tension axis in a WNW-ESE direction. This event occurred within the Pacific plate.
* On October 6, there was an M5.9 earthquake at a depth of approximately 55 km, offshore Fukushima 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 Pacific and the continental plates.
* On October 1, there was an M4.9 earthquake at a depth of approximately 5 km in the northern Ibaraki prefecture. The focal mechanism showed a normal fault type with a tension axis in an E-W direction. This event occurred within the crust.
* In the GNSS data for the Tokai region, there has been no unusual change of activity which is likely to be associated with the Tokai earthquake.
There was no remarkable activity.
* On October 19, there was an M5.6 earthquake at a depth of approximately 20 km (CMT solution), offshore north-east of Amami Oshima. The focal mechanism showed a normal fault type with a tension axis in an E-W direction. This event occurred within the Philippine Sea plate.
* On November 1, there was an M3.8 earthquake at a depth of approximately 10 km in the Kagoshima bay. The focal mechanism had a tension axis in a WNW-ESE direction. This event occurred within the crust.
* On November 3, there was an M5.0 earthquake at a depth of approximately 65 km offshore Tokachi. The focal mechanism had a tension axis in an NE-SW direction. This event occurred within the Pacific plate.
* On November 3, there was an M4.8 earthquake at a depth of approximately 10 km in the northern Ibaraki prefecture. The focal mechanism showed a normal fault type with a tension axis in an NE-SW direction. This event occurred within the crust.
Note: GNSS is a general name of satellite positioning system such as GPS.
November 10, 2017
Earthquake Research Committee
The following are the numbers of earthquakes by magnitude (M) that occurred in Japan and the surrounding area during October 2017.
(reference)
The following events for the period from October 2016 to late September 2017 have been listed as "Major Seismic Activities" in monthly "Evaluation of Seismic Activities."
| – Central Tottori Prefecture | M6.6 on October 21, 2016 (Depth of approximately 10 km) |
|
| – Offshore Fukushima Prefecture | M7.4 on November 22, 2016 (Depth of approximately 10 km) |
|
| – Northern Ibaraki Prefecture | M6.3 on December 28, 2016 (Depth of approximately 10 km) |
|
| – Offshore Fukushima Prefecture | M5.7 on February 28, 2017 (Depth of approximately 50 km) |
|
| – Bungo Channel | M5.0 on June 20, 2017 (Depth of approximately 40 km) |
|
| – Southern Nagano Prefecture | M5.6 on June 25, 2017 (Depth of approximately 5 km) |
|
| – Central and Eastern Iburi Region | M5.1 on July 1, 2017 (Depth of approximately 25 km) |
|
| – Aso Region, Kumamoto Prefecture | M4.5 on July 2, 2017 (Depth of approximately 10 km) |
|
| – Kagoshima Bay | M5.3 on July 11, 2017 (Depth of approximately 10 km) |
|
| – Southern Inland, Akita Prefecture | M5.2 on September 8, 2017 (Depth of approximately 10 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 unusual 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 30 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 30, 2017)
"There has been no unusual change of activity which is likely to be associated with the Tokai earthquake until now.(Excerpted)"
There is no supplementary information for Kinki-Chugoku-Shikoku region.
– The seismic activity in the Kagoshima bay after an M5.3 earthquake on July 11 continues, decaying as a whole.
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: