March 9, 2016
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
There was no remarkable activity.
There was no remarkable activity.
* On February 2, there was a Magnitude (M) 5.6 earthquake offshore Iwate prefecture. The focal mechanism of this event showed a normal fault type with a tension axis in an NNW-SSE direction.
* On February 5, there was a M4.6 earthquake at a depth of approximately 25 km in the eastern Kanagawa prefecture. The focal mechanism of this event showed a reverse fault type with a compression axis in an NW-SE direction.
* On February 7, there was a M4.4 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 NW-SE direction. This event occurred within the crust.
* On February 7, there was a M4.6 earthquake at a depth of approximately 45 km under the southern Ibaraki prefecture. 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 Philippine Sea and the continental plates.
* On February 15, there was a M6.0 earthquake at a depth of approximately 440 km under the ocean area near Torishima. The focal mechanism had a compression axis in a subducting direction of the Pacific plate. This event occurred within the Pacific 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.
There was no remarkable activity.
There was no remarkable activity.
* On February 6, there was a M6.4 earthquake near Taiwan. The focal mechanism of this event had a compression axis in an ENE-WSW direction.
* On March 3, there was a M4.9 earthquake at a depth of approximately 50 km, under the southern plains of Miyazaki prefecture. The focal mechanism had a tension axis in an E-W direction. This event occurred within the Philippine Sea 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.
March 9, 2016
Earthquake Research Committee
The following are the numbers of earthquakes by magnitude that occurred in Japan and the surrounding area during February 2016.
(reference)
The following events for the period from February 2015 to late January 2016 have been listed as "Major Seismic Activities" in monthly "Evaluation of Seismic Activities."
| – Southern Tokushima Prefecture | M5.1 on February 6, 2015 (Depth of approximately 10 km) |
|
| – Offshore Sanriku | M6.9 on February 17, 2015 | |
| – Offshore Iwate Prefecture | M5.7 on February 17, 2015 (Depth of approximately 50 km) |
|
| – Ocean Area near Yonagunijima | M6.8 on April 20 | |
| – Ocean Area near Torishima | M5.9 on May 3, 2015 | |
| – Offshore Miyagi Prefecture | M6.8 on May 13, 2015 (Depth of approximately 45 km) |
|
| – Ocean Area near Amami Oshima | M5.1 on May 22 (Depth of approximately 20 km) |
|
| – Northern Saitama Prefecture | M5.5 on May 25, 2015 (Depth of approximately 55 km) |
|
| – Offshore West of Ogasawara Islands | M8.1 on May 30 (Depth of approximately 680 km) |
|
| – Abashiri Region | M5.0 on June 4, 2015 (At a very shallow depth) |
|
| – Northern Inland of Iwate Prefecture | M5.7 on July 10, 2015 (Depth of approximately 90 km) |
|
| – Southern Oita Prefecture | M5.7 on July 13, 2015 (Depth of approximately 60 km) |
|
| – Tokyo Bay | M5.2 on September 12, 2015 (Depth of approximately 55 km) |
|
| – Central Coast of Chile | Mw8.3 on September 17, 2015 | |
| – 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) |
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 February 29 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, February 29, 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 is still continuing. This deformation is thought to be due to a slow slip (slow-slip) at the boundary between the Philippine Sea and the continental plates.
– A seismic activity is observed in the ocean area near Tokara Islands since February 3. 21 earthquakes with seismic intensity 1 or over occurred until February 14. The maximum earthquake is a M3.0 one which occurred on February 11.
There is no supplementary information for other regions.
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: