Geomagnetic variation and its relation to microearthquakes in the seismically inactive Korean Peninsula

Some microearthquakes that occur in the Korean Peninsula show significant geomagnetic variation when subjected to a specialized principal component analysis, wavelet-based semblance filtering and eigenvalue analysis. In this study, the principal component analysis was used to reconstruct and predict the geomagnetic field based on the past observed magnetic fields, and the reconstructed field was compared with the field observed during the earthquake event. The wavelet-based filtering showed improved results in delineating the earthquake event’s geomagnetic variations from their background field. Finally, the change in the tendency of the eigenvalues was detected by the analysis of three components of the geomagnetic fields during the earthquake event. The basement rock of the Korean Peninsula is known to have a highly resistive electrical structure that makes it possible for small-magnitude earthquakes to generate exaggerated geomagnetic variations. This is the first study reporting the relation between these earthquake events and the geomagnetic variations observed in the Korean Peninsula.