Major Asperities that Ruptured in Large California Earthquakes, Surrounding Pre-Shocks, and Some Yearly to Decadal Precursory Changes in Seismic Activity  

作　　者：Lynn R. Sykes Lynn R. Sykes(Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA)

机构地区：[1]Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA

出　　处：《International Journal of Geosciences》2025年第1期99-125,共27页地球科学国际期刊(英文)

摘　　要：Double-difference locations of forerunning shocks of seismic magnitude, M, 2 to 6 are examined in the months to decades before 11 mainshocks in California of magnitude 6 and larger. Each of the 11 had large quiet zones beforehand, which are called asperities, that break nearly entirely in large mainshocks. Their surrounding 11 zones were all sites of small to moderate-size shocks that define the approximate magnitudes of the coming large event. The latter, donuts of activity, are places to examine for precursory changes years to decades before larger earthquakes. The quiet asperities and many sites at the earth’s surface are not good places to monitor precursory changes before large mainshocks. Detecting forerunning events to large future earthquakes requires monitoring the right places. A few possible precursory changes are identified and discussed.Double-difference locations of forerunning shocks of seismic magnitude, M, 2 to 6 are examined in the months to decades before 11 mainshocks in California of magnitude 6 and larger. Each of the 11 had large quiet zones beforehand, which are called asperities, that break nearly entirely in large mainshocks. Their surrounding 11 zones were all sites of small to moderate-size shocks that define the approximate magnitudes of the coming large event. The latter, donuts of activity, are places to examine for precursory changes years to decades before larger earthquakes. The quiet asperities and many sites at the earth’s surface are not good places to monitor precursory changes before large mainshocks. Detecting forerunning events to large future earthquakes requires monitoring the right places. A few possible precursory changes are identified and discussed.

关 键 词：Active Faults Plate Boundaries California Double-Difference Locations San Andreas Fault ASPERITIES Forecasts Predictions SEISMOLOGY 

分 类 号：P31[天文地球—固体地球物理学]