Groundwater response analysis to multiple earthquakes on Jeju volcanic island

Earthquakes have been known to induce a groundwater response. This study statistically analyzed the relationship between the changes in groundwater level (oscillation) and seismic waves, as well as the relationship between the changes in groundwater level and earthquakes of various magnitudes and epicenters more than 1,000 km distance from Jeju Island. The analysis showed that the groundwater level in Jeju Island is changed mostly by earthquakes larger than M = 7.0 within a 3,000 km from the epicenter. A positive relationship appeared between the earthquake magnitude and groundwater level change. A similar positive trend was observed between the maximum groundwater level and the seismic amplitude of the earthquakes. Geologically and spatially, the northern area of the island showed the highest response to earthquakes, the southern area showed an intermediate response, and the western and eastern areas showed the lowest response. The highest groundwater response in the northern area might be linked to its permeable structures and geological layers.