Long-term patterns of earthquakes influenced by climate change: Insights from earthquake recurrence and stress field changes across the Korean Peninsula during interglacial periods

This study examined the temporal patterns of paleo-earthquake recurrences on the Korean Peninsula, situated near the Eurasian Plate boundary, by using electron spin resonance (ESR) dating to ascertain the ages at which fault gouge patches were reactivated. The findings reveal that the paleo-earthquakes in each of the fault zones (Keumwang, southern part of Wangsukcheon, Yangsan, and Ulsan) display quasiperiodic patterns. The observed patterns align with a time-dependent earthquake recurrence model. A periodicity of approximately 100 kyr could represent a regional baseline for fault activity. Over the past 650 kyr, the periodicity of paleo-earthquakes has coincided with the interglacial periods of marine isotope stages (MIS) 15, 13, 11, 9, and 7. On the Korean Peninsula, it is hypothesized that long-term differential stress changes, resulting from sea-level rises in the Pacific Ocean, have played a significant role in driving Quaternary fault activities during these interglacial stages. Consequently, this study suggests that the ongoing global warming trend could potentially increase the earthquake frequency on the Korean Peninsula.