Azimuthal differences and changes in strain rate and stress of the Japanese Islands deduced from geophysical data

Abstract Geodetic and seismological observations have shown discrepancies between azimuths of maximum contraction (strain rate) compression (stress). These can be the results superposition localized or transient mechanical processes such as fault coupling during seismic cycles. Rich sets recent geophysical data allow us to conduct spatiotemporal imaging discrepancies. Here, we estimate evolution in strain-rate fields Japanese Islands with optimized smoothing distances from 1997 2021 using Global Navigation Satellite System (GNSS) data, investigate how axes horizontal strain rates differ those stress based on earthquake focal mechanisms. Several characteristic are observed for each region within Islands. Both by more than 60° over hundreds kilometers Kanto along Nankai Trough, related seismotectonics due dual subduction Philippine Sea plate Pacific beneath The differences imply effect very long-term stable plate. We find that azimuthal tend small tectonic zones active inland earthquakes high back-arc sides. also 2011 off coast Tohoku caused notable region. strength may cause lower response sensitivity major geodetic rate. Our dataset has wide coverage serve a basis further research, example, current conditions Graphical