Three Dimensional Seismo-Tectonic Imaging: An Example from the Southern California Transverse Ranges

Peter A. Geiser, & Leonardo Seeber

Published July 2008, SCEC Contribution #388

We present a new technique to image deformation, 3D Seismo-tectonic Imaging, which juxtaposes instantaneous and accumulated deformation by combining earthquake and structural geology data. We test the technique using three independent data sets. We find concordance between the predicted finite deformation field and related instantaneous deformation surfaces inferred from aftershock and background seismicity data as well as structure imaged by seismic reflection data. These results indicate that; 1] The 1994 Northridge event ruptured a transverse, high-angle reverse fault linking two E-W striking listric thrust systems, the Pico and Oak Ridge. The rupture terminated on the thrusts and was capped by a north-dipping, forward-breaking imbricate of the Santa Susana fault.
2] The Los Angeles Seismic Zone is a region of thrusting associated with the development of a new mountain front forming south of the present one represented by the Santa Monica Anticline. The thrust is rooted on a mid-crustal ramp forming beneath the Los Angeles basin. We conclude that seismo-tectonic imaging by linking earthquake data to an empirically based quantitative description of the finite deformation field provides a new and fruitful method for integrating geological and seismological data.

Key Words
structural geology, seismology, California Transverse Range

Citation
Geiser, P. A., & Seeber, L. (2008). Three Dimensional Seismo-Tectonic Imaging: An Example from the Southern California Transverse Ranges. Journal of Structural Geology, 30(7), 929-945. doi: 10.1016/j.jsg.2008.02.010.