2024/05/08 by Qing‐Yu Wang, Xin Cui, William B. Frank +3 · 2 voices
Earth and Planetary Sciences · #High-pressure geophysics and materials #Seismic Waves and Analysis #earthquake and tectonic studies
paper · pdf · doi:10.1126/sciadv.ado1469
openalex publication_date 2024/05/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/04
The underlying mechanism of the ongoing seismic swarm in the Noto Peninsula, Japan, which generates earthquakes at 10 times the average regional rate, remains elusive. We capture the evolution of the subsurface stress state by monitoring changes in seismic wave velocities over an 11-year period. A sustained long-term increase in seismic velocity that is seasonally modulated drops before the earthquake swarm. We use a three-dimensional hydromechanical model to quantify environmentally driven variations in excess pore pressure, revealing its crucial role in governing the seasonal modulation with a stress sensitivity of 6 × 10 −9 per pascal. The decrease in seismic velocity aligns with vertical surface uplift, suggesting potential fluid migration from a high–pore pressure zone at depth. Stress changes induced by abnormally intense snow falls contribute to initiating the swarm through subsequent perturbations to crustal pore pressure.