Title: Determination of effective tectonic stress associated with earthquake faulting. The Tottori earthquake of 1943
Abstract: The records of the Tottori earthquake of 1943 (M = 7.4, 35.5° N, 134.2° E, depth 10 km) about by a low-magnification seismograph at a relatively short distance are used to determine dynamics fault parameters such as the particle velocity and the effective tectonic stress, in addition to static fault parameters such as the dislocation and the stress drop. The particle velocity of the fault motion is determined by comparing the initial slope of the observed seismogran with that of synthetic seismograms. Resolution sufficient for determining the rise time is obtained. The effective stress is determined from the particle velocity in the light of several dynamics fault models developed recently. The fault parameters thus determined, with supplementary data on the P-wave first motion, the aftershock and the triangulation, are: fault, type, vertical right-lateral strike slip; fault dimension, 33 km (lenght) × 13 km (width); strike, N 80° E; rupture velocity, 2.3 km/s (bilateral); average dislocation, 2.5 m; seismic moment, 3.6 × 1026 dyne · sm; rise time 3 s; particle velocity of the fault plane, 42 cm/s; stress drop, 83 b; effective tectonic stress, 30 to 100 b. The approximate agreement of the stress drop with the effective stress suggests that this earthquake represents an almost complete release of the effective tectonic stress. The seismic slip, 2.5 m, is in approximate agreement with the slip determined from the triangulation data over a period of 66 y, suggesting that the rate of the strain accumulation is very small in the epicentral area, the Japan Sea coast side of Honshu, Japan.
Publication Year: 1972
Publication Date: 1972-01-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 130
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot