HR: 1340h
AN: S13D-1083    [Abstracts]
TI: A Kinematic Source Time Function Compatible With Earthquake Dynamics: Relations Between Kinematic and Dynamic Parameters
AU: * Piatanesi, A
EM: piatanesi@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia, Department of Seismology and Tectonophysics, Via di Vigna Murata, 605, Rome, 00143 Italy
AU: Tinti, E
EM: tinti@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia, Department of Seismology and Tectonophysics, Via di Vigna Murata, 605, Rome, 00143 Italy
AU: Cocco, M
EM: cocco@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia, Department of Seismology and Tectonophysics, Via di Vigna Murata, 605, Rome, 00143 Italy
AU: Fukuyama, E
EM: fuku@bosai.go.jp
AF: National Research Institute for Earth Science and Disaster Prevention, 3-1 Tennodai, Tsukuba, 3050006 Japan
AB: We show in this study that the adoption in kinematic source models of slip-velocity time functions which are not consistent with the dynamic propagation of an earthquake rupture can affect the inferred dynamic traction evolution. To overcome this limitation, we propose a new source time function to be used in kinematic modeling of ground motion time histories which is compatible with elastodynamics and it makes feasible the dynamic interpretation of slip models. This function is derived from a different one, first proposed by Yoffe (1951), which models a slip velocity pulse propagating during the earthquake rupture. In order to remove its singularity at the crack tip, we apply a convolution with a triangular function and we obtain a regularized source time function called regularized Yoffe. We provide an analytical expression of this slip velocity time function and propose its parameterization in terms of the final slip, its duration and the duration of the positive slip acceleration. We use this function to prescribe the slip velocity history and compute the dynamic traction evolution on the fault plane through a 3D finite difference algorithm. We estimate the relevant dynamic parameters from the inferred traction evolution. Therefore, we examine the relations between kinematic and dynamic parameters, such as peak slip velocity, slip weakening distance (D$_c$) and breakdown stress drop. The inferred scaling relations are consistent with those proposed by Ohnaka and Yamashita (1989) from laboratory experiments. Our numerical simulations reveal that the inferred values of D$_c$ depend on the adopted slip velocity time function: they can range between 30% and 80% of the total slip. The source time function proposed in this study yields reasonable values of D$_c$ and includes the healing of slip.
DE: 7260 Theory and modeling
DE: 7209 Earthquake dynamics and mechanics
DE: 7212 Earthquake ground motions and engineering
DE: 7215 Earthquake parameters
SC: Seismology [S]
MN: 2004 AGU Fall Meeting