2025 Kamchatka earthquake

On 30 July 2025, at 11:24:52 PETT (29 July, 23:24:52 UTC), a M_w 8.7-8.8 megathrust earthquake struck off the eastern coast of the Kamchatka Peninsula in the Russian Far East, 119 km (74 mi) east-southeast of the coastal city of Petropavlovsk-Kamchatsky. It was the most powerful earthquake recorded worldwide since the 2011 Tōhoku earthquake, and is tied with the 1906 Ecuador–Colombia and 2010 Chile earthquakes as the sixth-strongest ever recorded by seismometers. However, it caused minimal damage compared to other earthquakes of similar magnitude. The earthquake caused moderate damage and multiple injuries in Kamchatka Krai and Sakhalin Oblast. The subsequent Pacific-wide tsunami was weaker than expected, with waves approximately 1 m (3 ft) or less in most places. However, a locally high run-up of 33.1 m (109 ft) was recorded in a steep narrow river valley near Vestnik Bay. One indirect fatality and 21 injuries were attributed to tsunami-related evacuations in Japan.

Tectonic setting

The earthquake occurred on the Kuril–Kamchatka subduction zone, a large thrust fault and convergent plate boundary between the Okhotsk plate and Pacific plate that extends from the east coast of the Kuril Islands to the Kamchatka Peninsula. Active subduction of the Pacific plate beneath the Okhotsk plate has been continuous since the Cretaceous. Estimates of the rate of convergence between these two plates varies between 76 and 90 mm (3.0 and 3.5 in) annually.

Large earthquakes on the subduction zone have been recorded before. The previous largest was the 1952 Severo-Kurilsk earthquake which measured M_w 8.8–9.0 and had an epicenter 45 km (28 mi) southeast of the 2025 earthquake. This event caused a large and destructive tsunami along the Kamchatka coast. It is believed to have ruptured a 700 km (430 mi) by 150–200 km (93–124 mi) section of the subduction zone from Shipunskii Cape in the north to Onekotan in the south. Unlike most large subduction earthquakes, the greatest fault movement in the 1952 event occurred at greater depth instead of being closer to the trench. Movement on the fault was inferred to be as deep as 40 km (25 mi) and possibly 60–80 km (37–50 mi). Little slip occurred at the trench, leaving it locked and accumulating unreleased elastic energy.

A larger earthquake occurred in 1737 and had a magnitude estimated at 9.3. This earthquake generated a tsunami 63 m (207 ft) high according to written records by travellers and tsunami deposit observations. In 1841, another earthquake with an estimated magnitude of 9.0 produced a major tsunami that was also recorded in Hawaii.

In a paper from Izvestiya, Physics of the Solid Earth dated to 23 July 2025, researchers studied ring-shaped seismicity in southern Kamchatka, a pattern in earthquakes where their epicenters are distributed around an elliptical "ring" shape. These events are often associated with the preparatory process of a large earthquake on an active fault. An analysis of earthquakes from 1973 to late 2024 revealed three ring-shaped seismicity structures at 0–33 km (0–21 mi), 34–70 km (21–43 mi), and 71–110 km (44–68 mi). Existing studies reported that a large earthquake usually occurs about 10 to 15 years after a sudden high rate of seismicity around these structures, and in the Kamchatka area, this occurred in 2016. The paper said there was a likelihood of a large earthquake occurring between 2026 and 2031 with a moment magnitude of 8.4–8.8.

Earthquake

The large submarine earthquake occurred on 29 July at 23:24:50 UTC with a moment magnitude (M_ww ) of 8.8, according to the United States Geological Survey (USGS). The International Seismological Centre (ISC) assigned the earthquake a moment magnitude of M_w 8.7. Its epicenter was off the Pacific coast of the Kamchatka Peninsula, about 136 km (85 mi) east-southeast of Petropavlovsk-Kamchatsky, while the hypocenter was put at a shallow depth of 35 km (22 mi). The National Institute of Geophysics and Volcanology and Geoscience Australia both put the magnitude at M_w 8.6.

The USGS said the earthquake occurred as a result of shallow reverse faulting on the subduction zone interface. They estimated the area where movement occurred on the interface to be 390 km (240 mi) by 140 km (87 mi). The rupture was believed to have re-ruptured the part of the fault that slipped in the M_w 9.0 1952 Severo-Kurilsk earthquake, and also filled any remaining seismic gap between the 1952 and 1923 Kamchatka earthquakes.

A foreshock, measuring M_w 7.4, struck on 20 July, about 60 km (37 mi) to the southwest of the 29 July mainshock. The foreshock was preceded by smaller earthquakes in the hour before, including a Mw 6.7 earthquake. At least 3,527 aftershocks followed, with 27 exceeding M_w 5.9, including a M_w 6.9 event at 00:09 UTC on 30 July, a M_w 6.8 on 3 August, a M_w 7.4 on 13 September, and a M_w 7.8 on 18 September.

In Japan, the earthquake was felt at an intensity of 2 on the Shindo scale in Hokkaido.

Characteristics

A finite fault model released by the USGS indicated slip on an approximately 600 km (370 mi) by 140 km (87 mi) segment of the Kuril–Kamchatka Trench up to a depth of 40 km (25 mi). A majority of the rupture propagated 500 km (310 mi) along the subduction zone from the hypocenter to the southwest as far as Onekotan Island, while the remaining 100 km (62 mi) propagated northeast towards offshore Cape Shipunskii, albeit producing only negligible amounts of slip (less than 7.186 m (23.58 ft)) in small patches close to the trench.

The model divided the fault into three segments based on the depth profile and dip angle. Segment 1 represented the part closest to the trench, extending 8 to 15 km (5.0 to 9.3 mi) in depth. Near the trench, slip values peaked at 21.4169 m (70.265 ft) at 10 km (6.2 mi) depth while at 15 km (9.3 mi) depth, another area of high slip (30.2475 m (99.237 ft)) was inferred.

This high slip zone extended into Segment 2 (15 to 30 km (9.3 to 18.6 mi) range), where 31.4138 m (103.064 ft) of slip was recorded. About 150 km (93 mi) southwest, another zone of peak slip is inferred with the maximum dislocation estimated at 40.3013 m (132.222 ft). These two zones of high slip is separated by a narrow zone of smaller slip (~23 m (75 ft)). The deepest portion of the rupture, represented by Segment 3, exhibited 9.9145 m (32.528 ft) of slip at ~40 km (25 mi) depth. Most coseismic displacements occurred on Segments 1 and 2 in a region southwest from the hypocenter at depths of 8 to 25 km (5.0 to 15.5 mi).

The GEOSCOPE Observatory estimated that the earthquake ruptured the subduction zone for a duration of more than 180 seconds. The USGS estimated the earthquake's duration to be about 270 seconds (four minutes and 30 seconds).

Geological effects

An eruption occurred on 30 July at Klyuchevskaya Sopka, a volcano on the Kamchatka peninsula, shortly after the earthquake, although the eruption was not directly caused by the earthquake, and activity at the volcano had been observed over the preceding days. On 3 August, Krasheninnikov, another volcano, generated a 6 km (3.7 mi) eruption plume. It was the first recorded eruption on the volcano since human observations began. The Institute of Volcanology and Seismology of the Russian Academy of Sciences said on 6 August that seven Kamchatka volcanoes had erupted due to the earthquake, an occurrence that had not been seen on the Kamchatka Peninsula in nearly 300 years.

Parts of the southern Kamchatka Peninsula shifted southeast by as much as 2 m (6 ft 7 in) according to the Geophysical Service of the Russian Academy of Sciences.

Tsunami

Warnings

Space

NASA's GNSS-based Upper Atmospheric Realtime Disaster Information and Alert Network (GUARDIAN), comprising a portion of the Global Navigation Satellite System, had an AI component installed the day before the earthquake, which informed scientists in near real-time of the tsunami crossing open ocean. The vast column of water uplifted over a wide area pushed up the mass of air above it, sending ripples of low-frequency sound and gravity waves upwards into the ionosphere, thus measurably perturbing the orbits of GPS satellites.

Asia

The Pacific Tsunami Warning Center (PTWC) warned of "hazardous tsunami waves" along the coasts of Russia and Japan. Authorities in Russia also issued tsunami warnings for the Kamchatka Peninsula and the Kuril Islands, which were cancelled on the evening of 30 July. On 3 August, a magnitude 7.0 aftershock off the Kuril Islands prompted Russian authorities to issue a tsunami warning in parts of Kamchatka, with the Ministry of Emergency Situations warning of waves of up to 18 cm (7.1 in). The alert was lifted later that day.