Foreshock Migration Preceding the 2025 Mw 8.8 Kamchatka Earthquake: Insights From Single‐Station Observations

Abstract We investigate the spatiotemporal evolution of foreshocks preceding the 2025 Mw 8.8 Kamchatka earthquake by applying single‐station analysis to waveforms recorded at the nearest seismic station. Our results reveal a southwestward migration of foreshocks toward the mainshock epicenter through multiple stages, with a migration speed of ∼7.0 km/day, comparable to that of slow slip events along subduction zones, suggesting that aseismic slip may accompany the foreshock activity. The foreshocks occurred near the southern edge of the reduced kinematic locking of plate interface, where the relatively young and warmer slab is subducting. Repeated migrating transients likely acted as efficient stress transfers, potentially associated with slow slip, progressively loading the nucleation area and promoting rupture initiation, while also contributing to the progressive weakening of the locked megathrust. Together, these observations support a model in which migrating foreshocks reflects progressive stress redistribution that prepares the fault for catastrophic failure.