A study on dynamic rupture process of an asperity and radiation of short-period seismic waves

凹凸体动态破裂过程及短周期地震波辐射研究

• 批准号: 20540407
• 负责人: KATO Naoyuki
• 金额: $ 1.33万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2008
• 资助国家: 日本
• 起止时间: 2008 至 2010
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-20540407/
• 关键词: 地震現象; アスペリティ; 短周期地震波; シミュレーション; エンベロープ; 応力集中; 応力降下量

We investigate effects of stress concentration at the rim of an asperity due to surrounding aseismic sliding through numerical simulations. The stress concentration due to aseismic sliding promotes earlier occurrence of seismic rupture. This results in lower average stress drop of earthquake. This effect of stress concentration at the rim of asperity may explain the difference in average stress drop between intraplate and interplate earthquakes. The stress concentration at the edge of an asperity affects rupture process of asperity, and the average stress drop of asperity rupture increases with fracture energy or critical slip-weakening distance. A numerical simulation is conducted for dynamic rupture process of a circular asperity, where stress concentration is generated at the rim of the asperity. Seismic rupture starts from a point of the stress concentrated rim and propagates bilaterally around the rim. A significant slip pulse is generated at the end of the rupture due to rupture front focusing. We compile spatial distributions of short-period seismic energy radiation on faults estimated from the envelope inversion method to obtain the scaling law, frequency dependence of seismic energy radiation, and locality.

我们通过数值模拟研究了周围抗震滑动导致的粗糙边缘应力集中的影响。地震滑动引起的应力集中促使地震破裂提前发生。这导致地震的平均应力降较低。粗糙边缘应力集中的这种效应可以解释板内地震和板间地震之间平均应力降的差异。凹凸体边缘的应力集中影响凹凸体的破裂过程，凹凸体破裂的平均应力降随着断裂能或临界滑移减弱距离的增加而增大。对圆形凹凸体的动态破裂过程进行了数值模拟，凹凸体边缘产生了应力集中。地震破裂从应力集中边缘的一点开始，并围绕边缘向两侧传播。由于破裂前沿聚焦，在破裂结束时会产生显着的滑移脉冲。我们编译了通过包络反演方法估计的断层上短周期地震能量辐射的空间分布，以获得标度律、地震能量辐射的频率依赖性和局部性。

项目成果

Numerical simulation of recurrence of asperity rupture in the Sanriku region, northeastern Japan

• DOI: 10.1029/2007jb005515
• 发表时间: 2008-06
• 期刊: Journal of Geophysical Research
• 作者: N. Kato

Seismogram envelope inversion for high-frequency seismic energy radiation from moderate to large earthquakes

中大地震高频地震能量辐射的地震记录包络线反演

• 发表时间: 2008
• 期刊: Advances in Geophysics 50
• 作者: M. Ichihara;M. Ripepe;A. Goto;H. Oshima;H. Aoyama;M. Iguchi;K. Tanaka and H. Taniguchi;中原恒
• 通讯作者: 中原恒

短周期地震の成因についての考察

短周期地震成因的思考

• 发表时间: 2008
• 期刊: 地震 61
• 作者: Yoshitaka Matsumura;Anjali Mahajan;Ming-Daw Tsai;Hiroshi Kihara;Iidaka et al.;宮武隆,三宅弘恵,木村武志,隅谷謙一
• 通讯作者: 宮武隆,三宅弘恵,木村武志,隅谷謙一

短周期地震波の成因の理解のために-数値シミュレーションによる考察(3)

为了理解短周期地震波的成因 - 使用数值模拟的考虑 (3)

• 发表时间: 2008
• 作者: 後藤章夫;M. Ripepe;G. Lacanna;宮武隆,隅谷謙一,三宅弘恵,木村武志
• 通讯作者: 宮武隆,隅谷謙一,三宅弘恵,木村武志

Dependence of earthquake stress drop on critical slip-weakening distance

地震应力降对临界滑移弱化距离的依赖性

• 发表时间: 2010
• 作者: A.Goto;J.Johnson;R.Sanderson;J.Anderson;N.Varley;Kato N.
• 通讯作者: Kato N.