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Geophysics and Seismology Commons

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Geology

Central Washington University

Paleoseismology

Publication Year

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Full-Text Articles in Geophysics and Seismology

Unusual Geologic Evidence Of Coeval Seismic Shaking And Tsunamis Shows Variability In Earthquake Size And Recurrence In The Area Of The Giant 1960 Chile Earthquake, M. Cisternas, E. Garrett, R. Wesson, T. Dura, Lisa L. Ely Mar 2017

Unusual Geologic Evidence Of Coeval Seismic Shaking And Tsunamis Shows Variability In Earthquake Size And Recurrence In The Area Of The Giant 1960 Chile Earthquake, M. Cisternas, E. Garrett, R. Wesson, T. Dura, Lisa L. Ely

All Faculty Scholarship for the College of the Sciences

An uncommon coastal sedimentary record combines evidence for seismic shaking and coincident tsunami inundation since AD 1000 in the region of the largest earthquake recorded instrumentally: the giant 1960 southern Chile earthquake (Mw 9.5). The record reveals significant variability in the size and recurrence of megathrust earthquakes and ensuing tsunamis along this part of the Nazca-South American plate boundary. A 500-m long coastal outcrop on Isla Chiloé, midway along the 1960 rupture, provides continuous exposure of soil horizons buried locally by debris-flow diamicts and extensively by tsunami sand sheets. The diamicts flattened plants that yield geologically precise ages to correlate …


Serial Ruptures Of The San Andreas Fault, Carrizo Plain, California, Revealed By Three-Dimensional Excavations, Jing Liu-Zeng, Yann Klinger, Kerry Sieh, Charles Rubin, Gordon Seitz Feb 2006

Serial Ruptures Of The San Andreas Fault, Carrizo Plain, California, Revealed By Three-Dimensional Excavations, Jing Liu-Zeng, Yann Klinger, Kerry Sieh, Charles Rubin, Gordon Seitz

All Faculty Scholarship for the College of the Sciences

It is poorly known if fault slip repeats regularly through many earthquake cycles. Well‐documented measurements of successive slips rarely span more than three earthquake cycles. In this paper, we present evidence of six sequential offsets across the San Andreas fault at a site in the Carrizo Plain, using stream channels as piercing lines. We opened a latticework of trenches across the offset channels on both sides of the fault to expose their subsurface stratigraphy. We can correlate the channels across the fault on the basis of their elevations, shapes, stratigraphy, and ages. The three‐dimensional excavations allow us to locate accurately …