At 23:24 on July 29, 2025 (UTC), a Mw 8.8 earthquake struck approximately 104 kilometers off the coast of the Kamchatka Peninsula, Russia. The event occurred at 20.7 kilometers depth as a shallow reverse megathrust along the Kuril-Kamchatka arc subduction zone. It is the strongest earthquake globally since Tōhoku in 2011, ranks among the ten largest earthquakes ever recorded instrumentally, and is the most powerful in the region since the Mw 9.0 Kamchatka event of 1952. Aftershocks from the earthquake have also been significant, with 24 exceeding Mw 5.0 recorded in the first 5 hours, the largest reaching Mw 6.9[1].
In the nearest city to the epicenter, Petropavlovsk-Kamchatsky, shaking reportedly reached Modified Mercalli Intensity of IX (violent) based on data submitted to the USGS ‘Did You Feel It?’ initiative[2]. There were local reports of building and infrastructure damage, as well as injuries. However, as is often the case with offshore megathrust earthquakes, the main concern wasn’t the ground shaking, but the tsunami it generated.
Tsunami warnings and evacuation orders were issued in several countries across the Pacific, including Russia, the U.S. (covering Alaska, Hawaii, Guam, and parts of the West Coast), Western Canada, Japan, the Philippines, and Central and South America. Wave heights across the U.S. reached around 1.1 - 2.5 meters, lower than initial estimates of up to 4 meters, although some areas along the Kamchatka Peninsula saw waves of up to 5 meters.
While wave heights along the U.S. West Coast remained modest, largely due to the long travel time from the epicenter which allowed wave energy to dissipate (Figure 1), the Kamchatka earthquake serves as a timely reminder of the country’s exposure to tsunami risk from both distant and near-field sources. From the devastation in Crescent City in 1964 to paleotsunami evidence stretching back centuries, the U.S. has a longer and more varied tsunami history than many realize. Here are five historical reminders that highlight the need for insurers and other risk managers to take the threat seriously.
Figure 1. Estimated tsunami wave travel times from Petropavlosk, Russia, across the Pacific Ocean. Source: NOAA National Centre for Environmental Information[3].
01
The Mw 9.1 Tōhoku megathrust earthquake struck off the northeastern coast of Honshu, Japan, on March 11, 2011, and triggered a tsunami which caused waves up to 40 meters high and inflicted huge amounts of damage along the coast of Japan. While the U.S. did not experience direct earthquake shaking, the tsunami propagated across the Pacific Ocean and impacted the U.S. West Coast and Hawaii. Waves of up to 2.4 meters led to $31 million in economic damages in Hawaii, and $100 million in mainland U.S. harbours and coastal infrastructure in California and Oregon ($43 million and $137 million respectively in 2025 dollars) [4].
02
The Mw 9.2 earthquake off Prince William Sound triggered a massive submarine landslide, resulting in devastating tsunamis that killed over 120 people in Alaska and destroyed much of Crescent City, California, with wave heights up to 6.4 meters. The tsunami caused around $15 million in economic loss in Crescent City alone ($154 million in 2025 dollars)[5]. Crescent City is particularly susceptible to tsunamis due to an underwater ridge just offshore, and it also recorded the highest waves along the continental U.S. for the recent Kamchatka earthquake (1.2 meters).
03
A Mw 8.6 earthquake in the Aleutians likely triggered a submarine landslide, generating a tsunami that killed 159 people in Hawaii, including schoolchildren in Hilo, and caused $25 million in economic damage ($413 million in 2025 dollars) and prompted the creation of the Pacific Tsunami Warning Center [6]. It showed how Alaskan events can drive deadly impacts across the Pacific, and how some smaller magnitude earthquakes can trigger disproportionately large and damaging tsunami waves.
04
Estimated at between Mw 8.7 and Mw 9.2, this massive rupture generated a trans-Pacific tsunami, with records in Japan of waves of up to 5 meters high, and caused widespread coastal flooding along the Pacific Northwest. It remains the most significant paleotsunami event tied to the U.S. West Coast. Geologists predict a similar event today could generate waves of up to 30 meters for parts of the U.S. West Coast. Scenarios suggest that should an event like this occur again today, economic losses could reach a staggering $70 billion for Washington, Oregon, and California alone[7].
05
Evidence of pre-historic tsunamis has been found along the west coast of the U.S., particularly in Washington, Oregon, and northern California. Geological records such as sand deposits and buried marsh soils suggest multiple large tsunami events over the past few thousand years[8].
Tsunamis may be rare, but as history shows, their impacts can be devastating and far-reaching. To ensure risk from this complex peril is not overlooked, exposures can be identified through geospatial analysis, taking into account known subduction zones and research insights, such as those derived from paleotsunami studies. From there, a combination of scenario-based and probabilistic modelling can be used to estimate potential losses, drawing on factors like bathymetry, nearshore topography, and the vulnerability of local assets. Finally, through bespoke risk transfer solutions and broader risk management strategies, tsunami risk can be managed in the context of the overall catastrophe footprint.
