TY - JOUR
T1 - The key frictional parameters controlling spatial variations in the speed of postseismic-slip propagation on a subduction plate boundary
AU - Ariyoshi, Keisuke
AU - Matsuzawa, Toru
AU - Hasegawa, Akira
N1 - Funding Information:
We thank Naoki Uchida for valuable discussion, James R. Rice for introducing us to Yajing Liu, two anonymous editors for their helpful comments, and our editor Scott King for patiently and kindly waiting for our revision. This study was partly supported by the Tohoku University Supercomputing System Information Synergy Center, by a Grant-in-Aid for Scientific Research (C) (KAKENHI) No. 15510145 from the Japan Society for the Promotion of Science (JSPS) and by a grant from the Ministry of Education, Culture, Sports, Science and Technology. This work was also conducted as part of the 21st COE program, ‘E-ASTEC’, at Tohoku University. Some of the figures were drawn using GMT developed by Wessel and Smith [37] .
PY - 2007/4/15
Y1 - 2007/4/15
N2 - We investigate relations between the postseismic-slip process, effective normal stress, and friction parameters for a rate- and state-dependent law using 3-D numerical simulations of a subduction zone. The results show that the postseismic propagation speed largely depends on A(= aσ) rather than (A - B) = σ(a - b) or dc, where a and b are the frictional parameters describing the friction law, σ is the effective normal stress, and dc is the characteristic slip distance. The duration of the postseismic slip is found to depend on dc and (a - b). Considering that postseismic slip propagates faster in shallower regions than in deeper regions for both our numerical simulations and observation off Sanriku, and that frictional parameter a is not likely to be several times smaller than that estimated from rock laboratory experiments, we conclude that effective normal stress mainly controls the spatial variations in the speed of postseismic-slip propagation for large earthquakes off Sanriku. Moreover, the effective normal stress much lower than lithostatic stress due to high pore pressure may explain the speed of aseismic slip propagation in other subduction zones as well as off Sanriku.
AB - We investigate relations between the postseismic-slip process, effective normal stress, and friction parameters for a rate- and state-dependent law using 3-D numerical simulations of a subduction zone. The results show that the postseismic propagation speed largely depends on A(= aσ) rather than (A - B) = σ(a - b) or dc, where a and b are the frictional parameters describing the friction law, σ is the effective normal stress, and dc is the characteristic slip distance. The duration of the postseismic slip is found to depend on dc and (a - b). Considering that postseismic slip propagates faster in shallower regions than in deeper regions for both our numerical simulations and observation off Sanriku, and that frictional parameter a is not likely to be several times smaller than that estimated from rock laboratory experiments, we conclude that effective normal stress mainly controls the spatial variations in the speed of postseismic-slip propagation for large earthquakes off Sanriku. Moreover, the effective normal stress much lower than lithostatic stress due to high pore pressure may explain the speed of aseismic slip propagation in other subduction zones as well as off Sanriku.
KW - after slip
KW - aseismic slip
KW - earthquake cycle
KW - effective normal stress
KW - rate- and state-dependent friction law
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U2 - 10.1016/j.epsl.2007.01.019
DO - 10.1016/j.epsl.2007.01.019
M3 - Article
AN - SCOPUS:33847618410
VL - 256
SP - 136
EP - 146
JO - Earth and Planetary Sciences Letters
JF - Earth and Planetary Sciences Letters
SN - 0012-821X
IS - 1-2
ER -