Why Kamchatka's giant earthquake sent a smaller tsunami across the Pacific
In 2025, along parts of Kamchatka's coast in Russia, a magnitude 8.8 earthquake caused a tsunami to surge nearly 20 meters (65 feet) above sea level. Yet across the Pacific, its waves were much smaller than those produced by the region's great 9.0 earthquake in 1952. How could the tsunami climb so high near the source yet have a comparatively modest impact far away?
In July 2025, a magnitude 8.8 earthquake struck near Kamchatka, Russia, and produced a tsunami that reached heights of up to 20 meters onshore. However, just months earlier, a magnitude 9.0 earthquake in the same region generated a much larger tsunami with waves over 20 meters high that caused widespread destruction. A new study from Stefano Lorito and colleagues explains why the more recent tsunami was weaker despite the larger earthquake.
The 2025 quake's energy was only about 10-20% of the 1952 quake's, and most of its movement occurred deep beneath the seabed rather than at shallower depths. This deep, less energetic movement limited the tsunami's strength as it traveled across the Pacific. However, near Kamchatka, some movement happened closer to the seabed and even reached a trench, allowing waves to grow dramatically as they approached the shore.
Factors like the shape of the seabed and the slope of the coast caused these waves to build up even higher on land. While the earthquake's size was key, the depth of its movement was also crucial in determining the tsunami's impact both near the source and far away. The study emphasizes the need for improved forecasting methods that combine ocean and land sensors with simulations to provide more accurate early warnings.
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