TY - JOUR
T1 - The State of Stress on the Fault Before, During, and after a Major Earthquake
AU - Brodsky, Emily E.
AU - Mori, James J.
AU - Anderson, Louise
AU - Chester, Frederick M.
AU - Conin, Marianne
AU - Dunham, Eric M.
AU - Eguchi, Nobu
AU - Fulton, Patrick M.
AU - Hino, Ryota
AU - Hirose, Takehiro
AU - Ikari, Matt J.
AU - Ishikawa, Tsuyoshi
AU - Jeppson, Tamara
AU - Kano, Yasuyuki
AU - Kirkpatrick, James
AU - Kodaira, Shuichi
AU - Lin, Weiren
AU - Nakamura, Yasuyuki
AU - Rabinowitz, Hannah S.
AU - Regalla, Christine
AU - Remitti, Francesca
AU - Rowe, Christie
AU - Saffer, Demian M.
AU - Saito, Saneatsu
AU - Sample, James
AU - Sanada, Yoshinori
AU - Savage, Heather M.
AU - Sun, Tianhaozhe
AU - Toczko, Sean
AU - Ujiie, Kohtaro
AU - Wolfson-Schwehr, Monica
AU - Yang, Tao
N1 - Publisher Copyright:
© Copyright 2020 by Annual Reviews. All rights reserved.
PY - 2020/5
Y1 - 2020/5
N2 - Earthquakes occur by overcoming fault friction; therefore, quantifying fault resistance is central to earthquake physics. Values for both static and dynamic friction are required, and the latter is especially difficult to determine on natural faults. However, large earthquakes provide signals that can determine friction in situ. The Japan Trench Fast Drilling Project (JFAST), an Integrated Ocean Discovery Program expedition, determined stresses by collecting data directly from the fault 1-2 years after the 2011 Mbinfweinf 9.1 Tohoku earthquake. Geological, rheological, and geophysical data record stress before, during, and after the earthquake. Together, the observations imply that the shear strength during the earthquake was substantially below that predicted by the traditional Byerlee's law. Locally the stress drop appears near total, and stress reversal is plausible. Most solutions to the energy balance require off-fault deformation to account for dissipation during rupture. These observations make extreme coseismic weakening the preferred model for fault behavior. Determining the friction during an earthquake is required to understand when and where earthquakes occur. Drilling into the Tohoku fault showed that friction during the earthquake was low. Dynamic friction during the earthquake was lower than static friction. Complete stress drop is possible, and stress reversal is plausible.
AB - Earthquakes occur by overcoming fault friction; therefore, quantifying fault resistance is central to earthquake physics. Values for both static and dynamic friction are required, and the latter is especially difficult to determine on natural faults. However, large earthquakes provide signals that can determine friction in situ. The Japan Trench Fast Drilling Project (JFAST), an Integrated Ocean Discovery Program expedition, determined stresses by collecting data directly from the fault 1-2 years after the 2011 Mbinfweinf 9.1 Tohoku earthquake. Geological, rheological, and geophysical data record stress before, during, and after the earthquake. Together, the observations imply that the shear strength during the earthquake was substantially below that predicted by the traditional Byerlee's law. Locally the stress drop appears near total, and stress reversal is plausible. Most solutions to the energy balance require off-fault deformation to account for dissipation during rupture. These observations make extreme coseismic weakening the preferred model for fault behavior. Determining the friction during an earthquake is required to understand when and where earthquakes occur. Drilling into the Tohoku fault showed that friction during the earthquake was low. Dynamic friction during the earthquake was lower than static friction. Complete stress drop is possible, and stress reversal is plausible.
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U2 - 10.1146/annurev-earth-053018-060507
DO - 10.1146/annurev-earth-053018-060507
M3 - Review article
AN - SCOPUS:85077606275
SN - 0084-6597
VL - 48
SP - 49
EP - 74
JO - Annual Review of Earth and Planetary Sciences
JF - Annual Review of Earth and Planetary Sciences
ER -