Journal of Natural Disaster Science
Journal of Natural Disaster Science, Volume 19, Number 2, 1997, pp.101f.
ESTIMATION OF STRONG GROUND MOTION IN KOBE CITY DURING THE 1995 HYOGO-KEN NANBU EARTHQUAKE AND ITS DESTRUCTIVE POWER IN RELATION TO BUILDING STRUCTURES
(Received 6 October, 1997 and revised form 2 June, 1998)
Abstract
Strong ground motions in Kobe City during the 1995 Hyogo-ken Nanbu earthquake were estimated analytically taking into account the deep irregular underground structure and the soft surface layers indicated strong nonlinearity. The destructive power of the ground motions are discussed in terms of structural response based on the strength demand spectra of the SDOF elastic-plastic response. The destructive power of the ground motions estimated by Motosaka and Nagano (1996) first are discussed. Then the ground motions along the fault-normal line through Kobe University estimated. These motions include relatively high frequency contents (10Hz), which suggest that ground motion exerted strong destructive power in the heavily damaged belt. Contour maps also were plotted both for the ground motion distribution and for the strength demand distribution throughout the entire urban Kobe area, starting from the variable rupture slip model of the source reported by Wald (1996). This was done to clarify the relation between structural damage and ground motion throughout the entire urban Kobe area during this disastrous earthquake. The investigated frequencies were 0-1Hz; frequencies less than 1Hz, because of the limitation of the source model. The estimated peak ground velocities (PGVs) and velocity waveforms are compared with those of the recorded motions. The relation between the strength demand of the ground motion and structural damage is discussed.
Key words
Hyogo-ken Nanbu Earthquake, deep irregular underground structure, ground motion distribution, destructive power of ground motion, strength demand spectra