Potential relationships between seismo-deformation and seismo-conductivity anomalies

This study examines the relationships between seismo-deformation and seismo-conductivity anomalies during two M6 earthquakes that occurred on March 27th and June 2nd, 2013 in Taiwan. The Hilbert-Huang Transform is applied on surface displacement data to remove the effects of noise, semi-annual and annual cycles, and the long-term plate movements. The residual displacements have similar orientations when earthquake-related stress accumulates in the crust. Once the accumulated stress approaches the threshold for fault rupture, the orientations of the residual displacements generally become random, except in a small region near the epicenter. Interestingly, high-conductivity anomalies, which can be detected from the 3-component magnetic data via the magnetic transfer function, exist in places very close to this small region near the epicenter. Spatial and temporal correlations between the high-conductivity anomalies and the small region of seismo-deformation anomalies suggest that electric charges may migrate and become trapped in the region during seismogenic processes due to differential stress accumulation. These electric charges form a high-conductivity material that affects the Parkinson vector of the geomagnetic field.