Deformation Anomalies of 2025 Kamchatka Earthquake

This paper is devoted to identifying the deformation anomalies in records of the remote unequal-arm laser strainmeters recording Kamchatka earthquakes. We have analyzed data from two North-South-oriented laser strainmeters with 52.5-meter measuring arms and one East-Westoriented laser strainmeter with a 17.5-meter measuring arm, installed in the south of the Primorsky Territory. Deformation anomalies were detected in the laser interference instruments’ records during recording of tsunamigenic earthquakes in July and September 2025. The main characteristics of a tsunami cannot be defined from the recorded deformation anomalies, but they can help calculate the magnitude of seabed displacement in the earthquake epicenter, which is what causes the tsunami.