Keywords
Kamchatka
Co-seismic deformation
focal mechanism
How to Cite
Abstract
The Mw 8.8 Kamchatka earthquake of July 29, 2025, represents one of the largest seismic events recorded in the Kuril-Kamchatka subduction zone. This study synthesizes and compares the focal mechanism solutions reported by major seismological agencies to derive a representative consensus double-couple solution and to model the coseismic deformation fields generated by the rupture. The angular quadratic mean difference among strike, dip, and rake parameters was used as the main metric of similarity between mechanisms. The consensus solution (strike= 203.5°, dip = 22.7°, rake= 70.1°) is consistent with megathrust faulting on the subduction interface. Based on the USGS finite rupture model, surface displacement and strain fields were computed using Okada’s (1985) elastic dislocation formulation. The results reveal horizontal displacements toward the trench, vertical subsidence to the northwest, and uplift to the southwest of the epicenter, with strain patterns correlating with aftershock distribution. The low angular dispersion (maximum rotation = 28.4°) confirms convergence among agency solutions. These findings contribute to a more reliable representation of rupture parameters and support regional seismic hazard modeling.
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