Holocene paleoseismicity, temporal clustering, and probabilities of future large (M > 7) earthquakes on the Wasatch fault zone, Utah

摘要: The chronology of M > 7 paleoearthquakes on the central five segments Wasatch fault zone (WFZ) is one best dated in world and contains 16 earthquakes past 5600 years with an average repeat time 350 years. Repeat times for individual vary by a factor 2, range from about 1200 to 2600 Four ruptured between ∼620 ± 30 1230 60 calendar B.P. remaining segment (Brigham City segment) has not 2120 100 Comparison WFZ space-time diagram synthetic paleoseismic histories indicates that observed temporal clusters gaps have equal probability (depending model assumptions) reflecting random coincidence as opposed intersegment contagion. Regional seismicity suggests exposure 50 years, earthquake anywhere within Front region, based Poisson model, 0.16 0.30, respectively. A fault-specific predicts year probabilities itself, 0.13 0.25, In contrast, segment-specific assume quasi-periodic recurrence behavior Weber, Provo, Nephi are less (0.01–0.07 years) than regional or estimates (0.25–0.30 years), due short elapsed compared intervals those segments. Brigham Salt Lake segments, however, time-dependent approach exceed specific probabilities. For segment, these elevated being approximately late Holocene time. significantly longer