HR: 1330h
AN: S52A-0132    [PDF]
TI: Physical Interpretation of Fling Step and Long-Period Rupture Directivity Pulse
AU: * Hisada, Y
EM: hisada@cc.kogakuin.ac.jp
AF: Kogakuin Univ. Dept. of Architecture, Nishi-Shinjuku 1-24-2, Tokyo, 163-8677 Japan
AU: Bielak, J
EM: bielak@cs.cmu.edu
AF: Department of Civil and Environmental Engineering Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 United States
AB: The long-period pulse and the fling step are the most prominent near-source effects, such as the 1995 Kobe and 1999 Taiwan earthquakes, respectively. In order to compute those near-source ground motions efficiently, we have recently proposed a new form of the representation theorem, in which the dynamic and static Green_fs functions in fault integrations were evaluated separately (Hisada and Bielak, 2003). Using this theoretical method, we found that the long-period pulse and the fling step were mainly composed of the dynamic and static Green_fs functions, respectively. The directivity pulse consists of mainly the dynamic Green_fs functions (i.e., the body and surface waves), while the fling step is composed of static Green_fs functions. Therefore, the long-period pulse attenuates on the order from the inverse of r to the inverse of the square root of r, where r is the distance between an observation station and an asperity of the fault, whereas the fling step attenuates rapidly on the order of the r squared. In this paper, we use this methodology to simulate the near-fault ground motion observed during the 1992 Landers earthquakes. The results show successfully the strong presence of the fling step and the directivity pulse on the near-fault ground motions.
UR: http://kouzou.cc.kogakuin.ac.jp/
DE: 7200 SEISMOLOGY
DE: 7209 Earthquake dynamics and mechanics
SC: Seismology [S]
MN: 2003 Fall Meeting