Field Survey of the 2025 Kamchatka Tsunami on Coasts of the North Kuril Islands, Russia (Second Kuril Strait)
摘要
On July 29, 2025, a strong earthquake near Kamchatka (Russia) generated a tsunami that spread across the entire Pacific Ocean. The tsunami had its strongest impact on the coast of the North Kuril Islands (Paramushir and Shumshu), causing significant destruction. During the first days after the earthquake, a field survey of tsunami traces on these islands was conducted in the area of the Second Kuril Strait (which divides these islands). The boundary of land inundation by tsunami waves was outlined using GPS. Runup heights were determined using GEBCO_2019 (a grid with 15 arc-second resolution) topographic maps installed into Google Earth. It should be noted that there is no good topographic map for the North Kuril Islands region, unlike for the Kamchatka Peninsula. Therefore, conducting field studies to document and preserve data on tsunami traces—which have a short lifespan and may be lost due to seasonal storms and coastal processes—is essential. The study area (Shumshu Island) is characterized by extreme inaccessibility and a complete lack of permanent population, making prompt documentation of tsunami traces critical. Existing estimates of tsunami heights based on topographic maps are approximate and require field verification. The results of field measurements provide a foundation for accurately determining tsunami heights using high-precision geodetic methods such as leveling. A primary analysis of our results indicated that the tsunami heights in Severo-Kurilsk town due to the 2025 earthquake were similar to those caused by the 1952 earthquake. This will allow for the refinement of existing models and assessments, increasing their accuracy for the purpose of assessing the region's tsunami risk. The observation results are summarized in this paper.