December 9, 2016
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
* On November 22, there was a Magnitude (M) 7.4 earthquake offshore Fukushima prefecture, and maximum seismic intensity 5 Lower was observed in Fukushima, Ibaraki and Tochigi prefectures. Tsunami with height of 1.4 m was observed at Sendai port, Miyagi prefecture. Also this event caused some damage with injured persons.
* On November 25, there was a M4.6 earthquake at a depth of approximately 25 km in the central northern Rumoi region. The focal mechanism showed a reverse fault type with a compression axis in an E-W direction. This event occurred within the crust.
* On November 12, there was a M5.9 earthquake at a depth of approximately 60 km offshore Miyagi 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 November 22, there was a M7.4 earthquake at a depth of approximately 10 km (due to CMT solution), offshore Fukushima prefecture. This event occurred within the crust of the continental plate. The focal mechanism showed a normal fault type with a tension axis in an NW-SE direction: the fault plane dips in an S-W direction. In addition to tsunami with height of 1.4 m at Sendai port, Miyagi prefecture, tsunami was observed along the Pacific coast of the area extending from Hokkaido to Wakayama prefecture and Izu-Ogasawara Islands. According to GNSS observation, was observed the crustal deformation following the event, such as the displacement of about 4 cm in N-W direction at Odaka station, Fukushima prefecture. In the vicinity of this event, 9 earthquakes of M5.0 or over occurred including a M6.2 one on November 24.
* On November 21, there was a M5.0 earthquake at a depth of approximately 15 km, offshore east of Chiba prefecture [offshore Ibaraki prefecture]. This event occurred within the crust of the continental plate.
* 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 November 19, there was a M5.4 earthquake at a depth of approximately 50 km, under southern Wakayama prefecture. The focal mechanism showed a strike-slip fault type with a tension axis in an ENE-WSW direction. This event occurred within the Philippine Sea plate.
* On November 11, there was a M4.2 earthquake at a depth of approximately 10 km in the Kumamoto region, Kumamoto prefecture. The focal mechanism showed a strike-slip fault type with a tension axis in an N-S direction. This event occurred within the crust.
* On December 6, there was a M4.5 earthquake at a depth of approximately 5 km in the Hida region, Gifu prefecture. The focal mechanism had a compression axis in an NW-SE direction (provisional). This event occurred within the crust.
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.
December 9, 2016
Earthquake Research Committee
The following are the numbers of earthquakes by magnitude that occurred in Japan and the surrounding area during November 2016.
(reference)
The following events for the period from November 2015 to late October 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) |
|
| – Central Tottori Prefecture | M6.6 on October 21, 2016 (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 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 November 28 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, November 28, 2016)
"No change of activity which is likely to be associated with the Tokai earthquake has been observed until now. (Excerpted)"
– In the central Tottori prefecture where a M6.6 earthquake occurred on October 21, there were 1 earthquake with maximum seismic intensity 3 and 33 earthquakes with seismic intensity 1 or over in November. The seismic activity still continues, decaying as a whole.
– 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.
– "On November 11, there was a M4.2 earthquake at a depth of
approximately 10 km in the Kumamoto region, Kumamoto prefecture. (Excerpted)"
In November, 1 earthquake with maximum seismic intensity 4 (0 in October) and 1 earthquake with maximum seismic intensity 3 (4 in October) occurred in the Kumamoto and Aso regions, Kumamoto prefecture. A series of seismic activity of the 2016 Kumamoto Earthquakes in the Kumamoto and Aso regions 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: