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3D simulation of near-fault strong ground motion: comparison between surface rupture fault and buried faultLiu Qifang (ÁõÆô·½)1, Yuan Yifan (Ô¬Ò»·²)1 and Jin Xing (½ð ÐÇ)1,2
1. Institute of Engineering
Mechanics, China Earthquake Administration, Harbin 150080, China Abstract:
In this paper, near-fault strong ground motions caused by a surface rupture
fault (SRF) and a buried fault (BF) are numerically simulated and compared by
using a time-space-decoupled, explicit finite element method combined with a
multi-transmitting formula (MTF) of an artificial boundary. Prior to the
comparison, verification of the explicit element method and the MTF is
conducted. The comparison results show that the final dislocation of the SRF is
larger than the BF for the same stress drop on the fault plane. The maximum
final dislocation occurs on the fault upper line for the SRF; however, for the
BF, the maximum final dislocation is located on the fault central part.
Meanwhile, the PGA, PGV and PGD of long period ground motions (¡Ü1 Hz) generated
by the SRF are much higher than those of the BF in the near-fault region. The
peak value of the velocity pulse generated by the SRF is also higher than the
BF. Furthermore, it is found that in a very narrow region along the fault trace,
ground motions caused by the SRF are much higher than by the BF. These results
may explain why SRFs almost always cause heavy damage in near-fault regions
compared to buried faults.
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