May 13, 2016
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
* On April 14, there was a magnitude (M) 6.5 earthquake in the Kumamoto region, Kumamoto prefecture, and on April 16, there was a M7.3 earthquake in the same region. These event had a maximum seismic intensity 7 observed in Kumamoto prefecture and caused damage. Then the seismic activity became high in the areas extending from the Kumamoto region, Kumamoto prefecture and the Aso region, Kumamoto prefecture to the central Oita prefecture.
There was no remarkable activity.
* On April 20, there was a M5.8 earthquake at a depth of approximately 50 km, offshore Fukushima prefecture. The focal mechanism showed a reverse fault type with a compression axis in a WNW-ESE direction. This event occurred on the boundary between the Pacific and the continental plates.
* On April 27, there was a M5.0 earthquake at a depth of approximately 50 km, offshore Miyagi prefecture. The focal mechanism showed a reverse fault type with a compression axis in a WNW-ESE direction. This event occurred on the boundary between the Pacific and the continental plates.
* On April 1, there was a M6.5 earthquake offshore southeast of Mie prefecture. The focal mechanism of this event showed a reverse fault type with a compression axis in an NW-SE direction. This event occurred on 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.
There was no remarkable activity.
* (See another article for the 2016 Kumamoto earthquake)
* On April 24, there was a M4.2 earthquake under the ocean area near Tokara Islands.
* On May 3, there was a M5.9 earthquake offshore east of Hokkaido.
Note:GNSS (Global Navigation Satellite System) is a general name of satellite positioning system such as GPS.
May 13, 2016
Earthquake Research Committee
The following are the numbers of earthquakes by magnitude that occurred in Japan and the surrounding area during April, 2016.
(reference)
The following events for the period from April 2015 to late March 2016 have been listed as "Major Seismic Activities" in monthly "Evaluation of Seismic Activities."
| – 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 April 25 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, April 25, 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.
– From the GNSS observation, non-stationary crustal deformation surrounding the Bungo Channel observed from around December, 2015 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.
There is no supplementary information for Kyushu-Okinawa 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: