Interactions of Earthquakes in Central Italy over the Past 100 Yr through Coulomb Stress Changes, and Implications for Seismic Hazards

摘要

Italy has a historical earthquake record that is complete for events with a magnitude above 5.8 since A.D. 1349, making it possible to study Coulomb failure stress changes (Delta CFS) over a long period. In this study, we investigated the interactions between moderate-to-large earthquakes through Delta CFS over 100 yr in central Italy. This region is characterized by intense seismicity with predominantly extensional components. Hence, earthquake hazard assessment is of great public concern. Besides, earthquake interactions on normal faults are relatively less studied compared to reverse and strike-slip faults. Delta CFS calculations in this study incorporated both coseismic stress transfer and postseismic viscoelastic relaxation, and found the epicenters of 13 out of 15 events located in positively stressed lobes induced by previous earthquakes, confirming a correlation between the Delta CFS pattern and locations of moderate-to-large earthquakes. Next, we estimated the current distribution of Delta CFS on active faults, and after a comprehensive analysis of Delta CFS accumulation, slip rates, historical seismicity, and locations of populated cities, we identified three regions of potential seismic hazards in this region.