Open AccessA static and dynamic finite element analysis of the 1971 San Fernando, California, earthquake
Author(s) -
McCowan D. W.,
Glover P.,
Alexander S. S.
Publication year - 1977
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1977.tb01294.x
Subject(s) - geology , finite element method , seismology , strong ground motion , displacement (psychology) , ground motion , earthquake simulation , slip (aerodynamics) , bar (unit) , geodesy , structural engineering , physics , engineering , psychology , oceanography , psychotherapist , thermodynamics
Summary A two‐dimensional finite element model was developed for the source region of the San Fernando earthquake. Stochastic inversion of the surface displacement data of Alewine was carried out to obtain estimates of the displacements and stress drops along the actual fault surface in the finite element model. We calculate an average slip of 222 cm with a rms fit to the data of 8 cm. The average computed stress drop was 290 bar, with a maximum of 650 bar. Using these calculated stresses in a dynamic model of the earthquake, we compute theoretical accelerograms for the Pacoima Dam site. For frequencies less than 2 Hz, we found that the observed accelerograms were fitted best by a model with a propagating source having a rupture velocity of approximately 2.5 km s −1 . These results suggest that the dynamic finite element method can be used to estimate strong earthquake ground motion from extended sources (earthquakes) in many different complex geologic structures.