May 14, 2026
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
* On April 1, a magnitude (M) 5.0 earthquake occurred in southern Ibaraki Prefecture, it recorded a maximum seismic intensity 5 Lower in Tochigi Prefecture.
* On April 18, an M5.0 earthquake occurred in northern Nagano Prefecture. it recorded a maximum seismic intensity 5 Upper within the prefecture. On the same day, a second earthquake with M5.1 occurred, recording a maximum seismic intensity 5 Lower. These earthquakes caused partial damage to residential buildings.
* On April 20, 2026, an M7.7 earthquake occurred offshore of Sanriku. It triggered a tsunami that reached a height of 79 cm at the Kuji Port observation point (Port and Harbor Bureau) in Iwate Prefecture and 39 cm at the Urakawa observation point (Port and Harbor Bureau) in Hokkaido (both provisional results). This earthquake recorded maximum seismic intensity 5 Upper in Aomori Prefecture. This resulted in damage and injuries. Additionally, it generated long-period ground motion of class 3 in the southern inland of Akita Prefecture and northern Miyagi Prefecture.
* On April 27, an M6.2 earthquake occurred in the southern Tokachi region. The quake recorded maximum seismic intensity 5 Upper in Hokkaido. This resulted in damage and injuries.
* On April 27, an M6.2 earthquake occurred in the southern Tokachi region at a depth of approximately 85 km. Its focal mechanism showed a tension axis oriented in the NNE-SSW direction, and it occurred within the Pacific Plate.
GNSS observations have revealed no evidence of crustal deformation associated with this earthquake.
* For more information about the M7.7 earthquake offshore of Sanriku on April 20, please refer to "Evaluation of Earthquake Offshore of Sanriku on April 20, 2026."
* On April 1, an M5.0 earthquake occurred in southern Ibaraki Prefecture at a depth of approximately 50 km. The earthquake focal mechanism indicated a reverse fault with a pressure axis oriented in the NW-SE direction. It occurred at the boundary between the Philippine Sea Plate and the continental plate.
GNSS observations have revealed no evidence of crustal deformation associated with this earthquake.
* On April 18, at 13:20 and 14:54, two earthquakes with M5.0 and M5.1, respectively, occurred in northern Nagano Prefecture at a depth of approximately 10 km. Their focal mechanisms indicated strike-slip faults with a pressure axis oriented in the NW-SE direction. These events occurred within the crust. Seismic activity persists. From April 18 to the end of the month,
37 earthquakes with seismic intensity 1 or greater were recorded.
This seismic activity zone is located close to the Itoigawa-Shizuoka- Tectonic Line fault zone.
GNSS observations have revealed slight crustal deformation linked to this earthquake.
There was no remarkable activity.
There was no remarkable activity.
* No unusual changes have been recorded that would suggest that the likelihood of a great earthquake occurring along the Nankai Trough has increased compared to that of a normal situation.
Note: GNSS is a general name of a satellite positioning system such as GPS.
#: The probability of a subduction-zone earthquake occurring within the next 30 years is as follows: Rank III: greater than 26%, Rank II: 3% ~ 26%, Rank I: less than 3%, Rank X: unknown (an immediate earthquake cannot be ruled out).
May 14, 2026
Earthquake Research Committee
The numbers of earthquakes by magnitude (M) in and around Japan in April 2026 are as follows.
(Reference)
The following events for the period from April 2025 until the end of March 2026 have been listed as "Major Seismic Activities" in the monthly "Evaluation of Seismic Activities."
| – 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) | ||
| – In 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) | ||
| – In eastern Shimane Prefecture | M6.4 on January 6, 2026 (Depth of approximately 10 km) | ||
There is no supplementary information for Hokkaido region.
There is no supplementary information for Tohoku region.
– GNSS observations suggest that the crustal deformation differs from the normal trend in the area stretching from the western Shizuoka to the eastern Aichi Prefectures, a phenomenon observed since early 2022. This change is believed to be the result of a long-term slow slip occurring deep within the boundary between the Philippine Sea Plate and the continental plate, which extends from the Atsumi Peninsula to Lake Hamana. The slip center is gradually shifting from the Atsumi Peninsula towards Lake Hamana.
There is no supplementary information for Kinki-Chugoku-Shikoku region.
– According to GNSS observations, crustal deformation has been observed northwest of Miyakojima Island since February 26 due to an increase in seismic activity. However, this has decreased since mid-March.
– "No unusual changes have been recorded that would suggest
that the likelihood of a great earthquake occurring along the Nankai Trough
has increased compared to that of a normal situation.":
(This evaluation corroborates with the views presented at the regular meeting of the Nankai Trough Earthquake Assessment Committee on May 12 (reference below).)
(Reference)
Recent Crustal Activity Around the Nankai Trough (Seismological and Volcanological Department, Japan Meteorological Agency, May 12, 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: