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An 8.8 magnitude earthquake struck off Kamchatka, Russia, on June 30, 2025, triggering a tsunami with waves over 3 meters high.
Experts rank it among the top 10 largest quakes recorded.
The tsunami has reached Japan and Hawaii, prompting alerts across the Pacific.
The quake occurred along the Aleutian Trench, a known hotspot for big earthquakes.
On June 30, 2025, an 8.8 magnitude earthquake off the east coast of Kamchatka, Russia, triggered a tsunami with estimated maximum wave heights exceeding 3 metres. Experts ranked this quake among the top 10 largest ever recorded.
The tsunami is travelling across the Pacific Ocean and has reached Japan and Hawaii.
Several alerts and advisories have been issued for California, Alaska, Papua New Guinea, Tokelau Island, Fiji, American Samoa, Indonesia, Peru, Australia, and other regions across the Pacific. The Indian National Centre for Ocean Information Services announced that there is no tsunami threat to India and the Indian Ocean.
This large 8.8 earthquake follows two other events that struck the same zone. On July 20, 2025, a magnitude 7.2 earthquake hit Russia’s Kamchatka Peninsula, according to INCOIS. In 2024, a magnitude 7.1 earthquake occurred in the same zone.
“Today, July 29th, we have just witnessed a magnitude 8.8 earthquake on this same subduction zone (July 30th local time). This subduction zone has now produced two of the world’s top-ten largest earthquakes (the other being a M9.0 in 1952),” Judith A Hubbard, an earthquake scientist and Kyle Bradley, a geologist, wrote in a newsletter titled Earthquake Insights. A subduction zone is a collision between two of Earth's tectonic plates, where one plate sinks into the mantle underneath the other plate.
The earthquake occurred along the Aleutian Trench, extending 2,900 kilometers from the Gulf of Alaska to Kamchatka peninsula in Russia. At this location, the Pacific plate and the North American are approaching each other at about 6 centimetres a year and the pacific plate is being subducted beneath the North American plate.
The boundary of the two plates has given rise to some of the largest earthquakes of the 20th century, according to the American Museum of Natural History.
“Big earthquakes are expected along the Aleutian trench. The 1964 Alaskan 9.2 earthquake originated in the same zone on the western side and the 1952 Kurilsk earthquake had a 9.0 magnitude,” CP Rajendran, adjunct professor at the National Institute of Advanced Sciences, told Down To Earth.
Hubbard and Bradely warned that more aftershocks can be expected, including some that may exceed magnitude 7. “There is also the potential that another large earthquake could be triggered on a nearby section of the megathrust fault,” they wrote.
Tsunamis usually occur in places with large faults that can generate large earthquakes. Most of these large faults are around the Pacific Ring of Fire. Between 1900 and 2015, 754 confirmed tsunamis have occurred, with 78 per cent of those events in the Pacific Ocean and 5 per cent in the Indian Ocean, according to the Global Historical Tsunami Database, according to NOAA.
The large magnitude of the July 30 earthquake has raised questions on the impact it could have on Earth’s rotation. The 2004 magnitude 9 Sumatran earthquake in Indonesia, for example, decreased the length of day by 2.68 microseconds.
It also shifted the mean North pole by about 2.5 centimetres, and altered the planet’s shape minutely. This led to a decrease in its oblateness, which is flattening on the top and bulging at the equator by about one part in 10 billion, according to NASA.
“Massive earthquakes cause mass distribution as movement of tectonic plates are involved in a big way. The magnitude 8.8 Kamchatka, Russia earthquake is also massive. The earth rotation changes because of this will emerge eventually,” Rajendran explained.
