February 10, 2026
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
* On January 6, a magnitude (M) 6.4 earthquake occurred in eastern Shimane Prefecture. It registered a maximum seismic intensity 5 Upper in Sakaiminato City, Hino Town, and Kofu Town in Tottori Prefecture, as well as in Matsue City and Yasugi City in Shimane Prefecture. Additionally, it generated a long-period ground motion class 4 in western Tottori Prefecture. The earthquake caused damage, including injuries. On the same day, an M5.1 event also occurred, registering a maximum seismic intensity 5 Lower.
* On January 12, an M5.1 earthquake occurred, followed by an M5.2 on January 13, and an M4.8 on January 28, all occurred in the northern and southern Soya regions. The focal mechanism of the M5.2 earthquake indicates a reverse fault with a pressure axis oriented in the E-W direction, whereas that of the M4.8 event shows a reverse fault with a pressure axis oriented in the ENE-WSW direction. These earthquakes occurred in the crust. Starting around 01:00 on January 12, a cluster of seismic activity was detected near their epicenters. Throughout January, 41 earthquakes with maximum seismic intensity 1 or greater were recorded.
* On January 13, an M6.3 earthquake occurred offshore southeast of Etorofu Island at a depth of approximately 30 km (CMT solution). Its focal mechanism shows a reverse fault type with a pressure axis oriented in the NW-SE direction.
* On January 15, an M5.6 earthquake occurred offshore of Kushiro at a depth of approximately 30 km. Its focal mechanism shows a reverse fault type with a pressure axis oriented in the NW-SE direction and occurred at the boundary between the Pacific and continental plates.
* On January 27, an M5.0 earthquake occurred offshore southeast of Nemuro Peninsula at a depth of approximately 40 km. Its focal mechanism indicates a tension axis oriented in the N-S direction and occurred within the Pacific Plate.
* On January 9, at 18:56 and 20:24, M4.3 and M4.2 earthquakes occurred in the northern inland of Akita Prefecture at depths of approximately 5 km and 10 km, respectively. The focal mechanism of the M4.3 event shows a reverse fault type with a pressure axis oriented in the E-W direction, whereas that of the M4.2 event shows a strike-slip fault type with a pressure axis oriented in the E-W direction. These events occurred within the crust.
* On January 11, an M5.1 earthquake occurred in the northern coast of Iwate Prefecture at a depth of approximately 65 km. Its focal mechanism indicates a pressure axis aligned with the subduction direction of the Pacific Plate and occurred within the Pacific Plate (on the upper surface of a double fault plane).
* On January 17 and 21, M5.4 and M5.3 earthquakes occurred offshore east of Aomori Prefecture at depths of approximately 35 km and 60 km, respectively. Their focal mechanisms show reverse faults with a pressure axis oriented in the WNW-ESE direction and occurred at the boundary between the Pacific and continental plates. In addition, on January 22, an M5.5 earthquake occurred at a depth of approximately 45 km. Its focal mechanism shows a normal fault type with a tension axis oriented N-S direction and occurred within the Pacific Plate. Since the M7.5 event on December 8, 2025, the seismic activity around these epicenters has remained high. Throughout January, 10 earthquakes with maximum seismic intensity 1 or greater were recorded. Seismic activity has been particularly intense near the source area of the M6.9 earthquake on December 12, 2025.
The seismic activity zone extended approximately 100 km eastward and 50 km north-south from the epicenter of the M7.5 earthquake. The source fault of the M7.5 earthquake, estimated from the analysis of GNSS observations, far-field seismic waves, and S-net hydrostatic pressure data, also extended over the same area. Furthermore, following the occurrence of the M7.5 earthquake, shallow ultra-low-frequency earthquakes and tremors have been detected in areas east of the seismic activity zone.
GNSS observations revealed that about 2 months after the M7.5 event, horizontal movements, likely post-seismic deformations, were detected mainly in Aomori Prefecture. This included an eastward shift of approximately 2 cm at the Higashidori observation point. The after-slip, inferred from the post-seismic deformation, is believed to persist in the region, including the focal area of the M7.5 event.
* On January 28, an M5.2 earthquake occurred offshore of Sanriku at a depth of approximately 20 km. Its focal mechanism indicates a reverse fault type with a pressure axis oriented in the WNW-ESE direction and occurred at the boundary between the Pacific and continental plates.
Seismic activity triggered by the earthquake offshore east of Aomori Prefecture (M7.5) on December 8 was observed to the north of this earthquake, whereas that from the offshore of Sanriku (M6.9) on November 9 was observed the southeast.
* On January 9, an M4.6 earthquake occurred offshore east of Chiba Prefecture (#1) at a depth of approximately 30 km. Its focal mechanism shows a reverse fault type with a pressure axis oriented in the N-S direction and occurred at the boundary between the Philippine Sea Plate and the continental plate.
* On January 10, an M5.5 earthquake occurred in the ocean near Ioto Island.
* On January 13, an M4.3 earthquake occurred in the Noto region, Ishikawa Prefecture, at a depth of approximately 10 km. This occurred within the crust.
* On January 15, at 14:40 and 14:48, M4.8 and M5.2 earthquakes occurred at very shallow depths in the Hida region, Gifu Prefecture (#2). Their focal mechanisms showed a strike-slip fault type with a pressure axis oriented in the NW-SE direction and occurred within the crust.
* On January 22, an M6.5 earthquake occurred in the ocean near Ioto Island at a depth of approximately 15 km (CMT solution). Its focal mechanism shows a strike-slip fault type with a pressure axis oriented in the NW-SE direction.
* On January 24, an M4.5 earthquake occurred in northern Ibaraki Prefecture at a depth of approximately 5 km. Its focal mechanism shows a normal fault type with a tension axis oriented in the NE-SW direction. This was an intraplate earthquake.
* On January 29, an M4.5 earthquake occurred in southern Chiba Prefecture at a depth of approximately 25 km. It occurred within the Philippine Sea Plate.
* On January 6, at 10:18 AM, an M6.4 earthquake occurred in eastern Shimane
Prefecture at a depth of approximately 10 km. The focal mechanism involved strike-slip faulting, with the pressure axis oriented in the WNW-ESE direction and occurred within the crust. Additionally, after the M6.4 earthquake, an M5.1 earthquake occurred at 10:28 on January 6, followed by an M5.5 earthquake at 10:37 on the same date. From January 6 to 31, 58 earthquakes with seismic intensity 1 or greater were recorded. Intense seismic activity persists within an area extending 10 km east-west.
GNSS observations indicated that this was accompanied by slight crustal deformation.
From January 5, microseismic activities, including an M3.3 earthquake, were observed near the epicenter. Based on the earthquake's focal mechanism, the distribution of seismic activity, and analysis of GNSS observations, the estimated source fault was a right-lateral strike-slip fault extending approximately 10 km in the ENE-WSW direction.
This earthquake occurred in the northern zone identified by the Earthquake Research Committee in its "Long-Term Evaluation of Active Faults in the Chugoku Region (First Edition)." This area is assessed as having relatively active seismic activity, even though it contains few active faults. Furthermore, GNSS observations indicate the existence of an area called a strain concentration zone in the San'in region.
Near this earthquake, an M5.5 earthquake occurred six days after an M5.3 earthquake in western Tottori Prefecture in October 1989. Furthermore, in November 1990, a sequence of earthquakes occurred in the same region: an M4.8 quake followed just one minute after an M5.1 earthquake, an M5.2 earthquake occurred two days later, and another M5.1 earthquake occurred ten days after that.
There was no remarkable activity.
* There has been observed no unusual change which indicates that the possibility of occurrence of a great earthquake along the Nankai Trough has relatively risen compared to the normal time.
#1: The place name of the epicenter used by the JMA in its information release was "northeastern Chiba Prefecture."
#2: Regarding the M4.8 earthquake that occurred at 14:40, the epicenter location name used by the Japan Meteorological Agency in its information release was "Eastern Toyama Prefecture."
Note: GNSS is a general name of a satellite positioning system such as GPS.
February 10, 2026
Earthquake Research Committee
The numbers of earthquakes by magnitude (M) in and around Japan in January 2026 are as follows.
(Reference)
The following events for the period from January 2025 until the end of December 2025 have been listed as "Major Seismic Activities" in the monthly "Evaluation of Seismic Activities."
| – Under the Hyuganada Sea | M6.6 on January 13, 2025 (Depth of approximately 35 km) |
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| – In Aizu, Fukushima Prefecture | M5.2 on January 23, 2025 (Depth of approximately 5 km) |
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| – In northern Nagano Prefecture | M5.1 on April 18, 2025 (Depth of approximately 15 km) |
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| – In the ocean near Tokara Islands | M5.3 on June 30, 2025 | ||
| – In the ocean near Tokara Islands | M5.1 on July 2, 2025 | ||
| – In the ocean near Tokara Islands | M5.6 on July 2, 2025 | ||
| – In the ocean near Tokara Islands | M5.5 on July 3, 2025 (Depth of approximately 10 km) |
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| – In the ocean near Tokara Islands | M5.4 on July 5, 2025 | ||
| – In the ocean near Tokara Islands | M4.9 on July 6, 2025 | ||
| – In the ocean near Tokara Islands | M5.5 on July 6, 2025 | ||
| – In the ocean near Tokara Islands | M5.1 on July 7, 2025 | ||
| – Offshore east of the Kamchatka Peninsula, Russia | M8.8 on July30, 2025 | ||
| – In the ocean near Tokara Islands | M4.7 on September 17, 2025 | ||
| – Offshore southeast of the Nemuro Peninsula | M5.8 on October 25, 2025 (Depth of approximately 40 km) |
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| – Offshore of Sanriku | M6.9 on November 9, 2025 (Depth of approximately 15 km) | ||
| – Aso region, Kumamoto Prefecture | M5.8 on November 25, 2025 (Depth of approximately 10 km) | ||
| – Offshore east of Aomori Prefecture | M7.5 on December 8, 2025 (Depth of approximately 55 km) | ||
There is no supplementary information for Hokkaido region.
There is no supplementary information for Tohoku region.
– According to the GNSS observations, the crustal deformation differs from the ordinary trend for the area extending from the western Shizuoka to the eastern Aichi Prefectures has been observed since early 2022. This change is believed to result from long-term slow slip occurring deep within the boundary between the Philippine Sea Plate and the continental plate extending from the Atsumi Peninsula to Lake Hamana. The slip center is gradually shifting from the Atsumi Peninsula toward Lake Hamana.
– "On January 13, an M4.3 earthquake occurred in the Noto region, Ishikawa Prefecture, at a depth of approximately 10 km. This occurred within the crust.":
For information on the series of seismic events that have occurred since December 2020, please refer to "Recent Seismic Activity of the '2024 Noto Peninsula Earthquakes' (Published on January 14, 2026)."
– Between December 31 and January 8, deep low-frequency earthquakes (tremors) were detected in western Shikoku, near the boundary between the Philippine Sea Plate and the continental plate. Strain data, GNSS observations, and tilt data indicate that the slight crustal deformations observed in the area were almost synchronized with this deep low-frequency seismic activity. This phenomenon is believed to result from a short-term slow slip occurring at the deep boundary between the Philippine Sea Plate and the continental plate.
There is no supplementary information for Kyushu-Okinawa region.
– "No unusual changes have been observed that would indicate
an increased likelihood of a great earthquake occurring along the Nankai
Trough compared to normal time.":
(This evaluation corroborates the views presented at the regular meeting
of the Nankai Trough Earthquake Assessment Committee on February 6 (reference
below).)
(Reference)
Recent Crustal Activity Around the Nankai Trough (Seismological and Volcanological Department, Japan Meteorological Agency, February 6, 2026)
"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 risen compared to the normal time (Excerpted)."
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: