Recent Developments in Rock Mechanics as Applied to Earthquake Dynamics

This contribution summarizes some new findings related to the applied study of rock- and geomechanics in the field of engineering seismology. Our interest here is especially devoted to the influence of high-frequency seismic waves on the damage of underground structures, which are considered to be earthquake-resistant: On the occasion of the 1995 Hyogo-ken Nanbu (Kobe) and the 2004 Niigata-ken Chuetsu, Japan, earthquakes, unique and previously unrecognised damage to the underground structures was found both at depth and near the surface. Two-dimensional elastodynamic analyses "inversely" show that the observed damage patterns were induced most likely by the dynamic interaction of vertical (longitudinal) oscillations of relatively high frequencies with the tunnels. The results also suggest that, contrary to the structures on the surface, underground structures subjected to dynamic waves vibrate with their surroundings and they are expected to function as sensors that respond only to waves of specific characters.