Characteristics and damage investigation of 1993 Hokkaido Nansei-oki earthquake

This paper describes the characteristics and earthquake damage of 1993 Hokkaido Nansei-oki Earthquake (M=7.8) by the recorded strong motion accelerograms and damage investigations perfomed a few days later the earthquake by CRIEPI researchers.(AU)

Evaluation for earthquake ground motion of sediment-filled basin under seismic observation

Characteristics of Earthquake ground motion and seismic wave propagation were investigated with reference to earthquake records, which were obtained at K site of horizontal sedimentary layer and at O site of sediment-filled basin. Seismic response analyses were also examined by comparing with those records.(AU)

Experimental study of effects of liquefaction - induced ground displacement on in - ground structures

The authors have conducted the following experiments to investigate the fundamental characteristics of the effect that liquefaction-induced ground displacements have on in-ground structures: (i) experiments to measure the pressure of liquefied soil on a rigid in-ground wall (ii) experiments to measure the effects of liquefaction-induced ground displacements on a pile (iii) experiments on the load acting on spheres moving in liquefied soil. From these experiments it was concluded that the pressure exerted by liquefied soil on a rigid in-ground wall was approximately equal to the pressure of a liquid with an equivalent specific gravity. The force due to laterally flowing ground on in-ground structures did not depend on the magnitude of the ground displacement, but was greatly affected by the flow velocity.(AU)

Case histories of relationship between wooden house damage and lateral geologic inhomogeneity

Wooden house damages caused during three of the past earthquake in Japan, the 1923 Kanto, the 1978 Mijagi-Ken-Oki, and the 1987 Chiba-Ken-Toho-Oki earthquakes have already been studied extensively and in detail. Moreover, soil condition surveys were conducted in the areas where structursl danaged were predominant have been investigated. In this paper, in order to study the local site effects pf lateral geologic inhomogeneity on surface ground motion during earthquakes, relationship between wooden house damaged due to resonance of ground motion and the ground condition of the damaged house distributed area surveys.(AU)

Response caracteristics of thick sedimentary layers based on the deep vertical array observation

This paper describes the results of deep vertical array observation perfomed to understand responses of thick sedimentary horizontal layers. Acceleration responses are evaluated at 9 different levels from the bottom of the boring hole (about-500m) to the ground surface. Moderate nonlinear responses of the near surface layer are observed with the maximum surface acceleration of about 0.1G. Giving the deepest record, numerical simulations are carried out to validate a one-dimensional wave propagation analysis. Moreover, a comparison between an equivalent linear analysis and an effective stress analysis is made to observe the difference due to modelling of soil nonlinearity.(AU)