Uenishi Koji
School of Engineering, The University of Tokyo.
Proc Jpn Acad Ser B Phys Biol Sci. 2017;93(1):28-49. doi: 10.2183/pjab.93.003.
Normally, an earthquake is considered as a phenomenon of wave energy radiation by rupture (fracture) of solid Earth. However, the physics of dynamic process around seismic sources, which may play a crucial role in the occurrence of earthquakes and generation of strong waves, has not been fully understood yet. Instead, much of former investigation in seismology evaluated earthquake characteristics in terms of kinematics that does not directly treat such dynamic aspects and usually excludes the influence of high-frequency wave components over 1 Hz. There are countless valuable research outcomes obtained through this kinematics-based approach, but "extraordinary" phenomena that are difficult to be explained by this conventional description have been found, for instance, on the occasion of the 1995 Hyogo-ken Nanbu, Japan, earthquake, and more detailed study on rupture and wave dynamics, namely, possible mechanical characteristics of (1) rupture development around seismic sources, (2) earthquake-induced structural failures and (3) wave interaction that connects rupture (1) and failures (2), would be indispensable.
通常情况下，地震被视为固体地球破裂（断裂）产生的波动能量辐射现象。然而，震源周围动态过程的物理学原理，这可能在地震发生和强波产生中起关键作用，尚未得到充分理解。相反，地震学以前的许多研究是根据运动学来评估地震特征的，运动学并不直接处理这些动态方面，通常排除了频率超过1Hz的高频波分量的影响。通过这种基于运动学的方法获得了无数有价值的研究成果，但也发现了一些难以用这种传统描述来解释的“异常”现象，例如，在1995年日本兵库县南部地震时，对破裂和波动动力学进行更详细的研究，即（1）震源周围破裂发展、（2）地震引起的结构破坏以及（3）连接破裂（1）和破坏（2）的波相互作用的可能力学特性，将是不可或缺的。
