July 11, 2022
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
* On June 19, there was a magnitude (M) 5.4 earthquake in the Noto region, Ishikawa prefecture. Maximum seismic intensity 6 Lower was observed in Ishikawa prefecture, and was caused damage with injured persons.
* On June 26, there was an M4.7 earthquake in the Kumamoto region, Kumamoto prefecture. Maximum seismic intensity 5 Lower was observed in Kumamoto prefecture.
* On June 20, there was an M4.4 earthquake at a depth of approximately 10 km in the northern Soya region. This event occurred within the crust.
* On June 12, there was an M5.1 earthquake at a depth of approximately 55 km, offshore Fukushima prefecture. The focal mechanism had a compression axis in a WNW-ESE direction. This event occurred within the Pacific plate.
In the vicinity of the recent event, on March 16, 2022 there was an M7.4 earthquake within the Pacific plate. From March 16 till July 8 at 09 o'clock (JST) there occurred 162 earthquakes with seismic intensity 1 or over observed: from June 1 till July 8 at 09 o'clock (JST) 19 earthquakes. Though the seismic activity still continues, it is decaying with time.
* With regard to the earthquake in the Noto region, Ishikawa prefecture on June 19, refer to another report (Evaluation of Earthquake in the Noto Region, Ishikawa Prefecture).
* On June 21, there was an M6.1 earthquake at a depth of approximately 10 km (CMT solution) in the ocean near Chichijima Island. The focal mechanism showed a reverse fault type with a compression axis in an E-W direction. This event occurred at the boundary between the Pacific and the Philippine Sea plates.
* On June 17, there was an M4.9 earthquake at a depth of approximately 45 km under the southern Tokushima prefecture. The focal mechanism showed a normal fault type with a tension axis in an ENE-WSW direction. The event occurred within the Philippine Sea plate.
* Within the continental plate offshore northwest of Okinawa Main Island, an active seismic activity is observed from January 30, and till July 8 at 09 o'clock (JST), there occurred 62 earthquakes with seismic intensity 1 or over. From June 1 till July 8 at 09 o'clock (JST), there occurred 14 earthquakes. In the series of seismic activity, till July 8 at 09 o'clock (JST) there occurred 18 earthquakes of M5.0 or over, the largest being M5.9 earthquakes on March 17 and June 3.
According to the GNSS observation, crustal deformation was observed from about February 2022 such as a south-southeastward displacement of 1 cm over of Gushikawa observatory, Kumejima Town, Okinawa prefecture.
In the neighborhood of the area of the recent seismic activity, there were several seismic clusters: from February to March 1980 and in August 2007, there were clusters including earthquakes of M6.0 or over. In the seismic activity from February to March 1980, there were M6.7 and M6.3 earthquakes.
* On June 26, there was an M4.7 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 NNW-SSE direction. This event occurred within the crust.
According to the GNSS observation, no significant crustal deformation associated with the recent event was observed.
* There has been observed no unusual change which indicates that the possibility of occurrence of great earthquakes along the Nankai Trough has relatively raised compared to the normal time.
* On June 20, there was an M6.4 earthquake at a depth of approximately 10 km (CMT solution) near Taiwan. The focal mechanism showed a reverse fault type with a compression axis in an NW-SE direction.
* On July 2, there was an M5.9 earthquake at a depth of approximately 320 km under the Soya Strait. The focal mechanism had a compression axis in the subducting direction of the Pacific plate. This event occurred within the Pacific plate. Seismic intensity 3~1 was observed in the area extending from Hokkaido to Tohoku regions: in addition to epicentral area, the ground quake was large also along the Pacific side of the area from Hokkaido to Tohoku regions due to the seismic waves which propagated through the subducting Pacific plate (abnormal seismic intensity area).
* On July 5, there was an M4.9 earthquake at a depth of approximately 55 km, under the eastern Hidaka region. 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 July 6, there was an M5.4 earthquake at a depth of approximately 65 km, offshore Miyagi prefecture. The focal mechanism showed a reverse fault type with a compression axis in an NW-SE direction. This event occurred within the Pacific plate.
Note: GNSS is a general name of satellite positioning system such as GPS.
July 11, 2022
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
The following are the numbers of earthquakes by magnitude (M) that occurred in Japan and the surrounding area during June 2022.
(Reference)
The following events for the period from June 2021 to late May 2022 have been listed as "Major Seismic Activities" in monthly "Evaluation of Seismic Activities."
| – In the Noto Region, Ishikawa Prefecture | M5.1 on September 16, 2021 (Depth of approximately 15 km) |
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| – Offshore Iwate Prefecture | M5.9 on October 6, 2021 (Depth of approximately 55 km) |
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| – Under the Northwestern Chiba Prefecture | M5.9 on October 7, 2021 (Depth of approximately 75 km) |
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– Under the Eastern and Fujigoko Regions, |
M4.8 on December 3, 2021 Regions, Yamanashi prefecture |
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| – Under the Kii Channel | M5.4 on December 3, 2021 (Depth of approximately 20 km) |
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| – In the Ocean near Tokara Islands | M6.1 on December 9, 2021 | ||
| – Under the Ocean near Chichijima Island | M6.1 on January 4, 2022 (Depth of approximately 60 km) |
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| – Under the Hyuganada |
M6.6 on January 22, 2022 (Depth of approximately 45 km) |
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| – Offshore Fukushima Prefecture | M7.4 on March 16, 2022 (Depth of approximately 55 km) |
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| – Offshore Iwate Prefecture | M5.6 on March 18, 2022 (Depth of approximately 20 km) |
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| – Under the Northern Ibaraki Prefecture | M5.4 on April 19, 2022 (Depth of approximately 95 km) |
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| – Offshore Ibaraki Prefecture | M6.0 on May 22, 2022 (Depth of approximately 5 km) |
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There is no supplementary information for Hokkaido region.
There is no supplementary information for Tohoku region.
There is no supplementary information for Kanto-Chubu region.
– In the crust of the southern Kyoto prefecture, the seismic activity became high since March 31. The largest are 2 M4.4 earthquakes which occurred on March 31 and May 2. From March 31 till June 30, there occurred 16 earthquakes with seismic intensity 1 or over. Of these there occurred 4 earthquakes with seismic intensity 3 or over. From June 1 till 30 there occurred 1 earthquake with seismic intensity 1 or over. Though the seismic activity still continues, it is decaying with time.
In the vicinity of the recent seismic activity, there was a cluster from February to March, 1999: an M4.2 earthquake on February 12 and an M4.0 on March 12.
– According to the GNSS observation, the crustal deformation different from the ordinary trend in the central Shikoku has been observed from about spring 2019. This phenomenon is considered to be caused by a long-term slow-slip around the central Shikoku at the deeper part of the boundary between the Philippine Sea and the continental plates.
– According to the GNSS observation, the crustal deformation different from the ordinary trend in the western Kii Peninsula and the eastern Shikoku has been observed from about summer 2020. This phenomenon is considered to be caused by a long-term slow-slip around the Kii Channel at the deeper part of the boundary between the Philippine Sea and the continental plates.
– According to the GNSS observation, the crustal deformation different from the ordinary trend in the southern Kyushu, being observed from about summer 2020, is considered to be caused by a long-term slow-slip around the southern Hyuganada at the deeper part of the boundary between the Philippine Sea and the continental plates. Recently this crustal deformation seems to be stagnant.
– "There has been observed no unusual change which indicates
that the possibility of occurrence of great earthquakes along the Nankai
Trough has relatively raised compared to the normal time.":
(here has been observed no unusual change which indicates that the possibility of occurrence of great earthquakes along the Nankai Trough has relatively raised compared to the normal time. (reference below).)
(Reference)
Recent Crustal Activity Around the Nankai Trough (Seismological and Volcanological Department, Japan Meteorological Agency, July 7, 2022)
"In the present, there has been observed no unusual change which indicates that the possibility of occurrence of great earthquakes along the Nankai Trough has relatively raised compared to the normal time.. (Excerpted)"
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: