Recent Rupture History of the Coastal Fault Zone between Punta Banda
and the Los Angeles Basin

by Lisa Grant
Dept. Environmental Analysis and Design
University of California, Irvine

3-4pm
Friday January 31, 2003
Refreshments served at 2:45pm
Munk Conference Room
Cecil and Ida M. Green Institute of Geophysics and Planetary Physics
Scripps Institution of Oceanography
University of California, San Diego
http://mahi.ucsd.edu/seminar/

Abstract

In this talk I will present a compilation and synthesis of observations
from paleoseismic research along a > 300-km-length zone of faults that
appear to be kinematically linked. At a minimum, the Coastal Fault Zone
extends from Beverly Hills, California (USA) southeast to the Punta
Banda peninsula in Baja California (Mexico), and includes both onshore
and offshore sections with different names. From north to south, these
faults include the Newport-Inglewood Fault Zone (NIFZ), the San Joaquin
Hills fault, the offshore NIFZ, the Rose Canyon fault, the Descanso strand
of the offshore Coronado Bank fault, and the Agua Blanca fault on the
Punta Banda peninsula. Historic and paleoseismic records indicate that
the entire Coastal Fault Zone between the Agua Blanca and the southern
NIFZ has ruptured in a cluster or series of earthquakes since ~1640
A.D., with the possible exception of the northern NIFZ and portions
of the offshore NIFZ. The 1933 Mw6.4 earthquake on the southern NIFZ
increased the Coulomb stress on the northern NIFZ in Los Angeles, and
recent seismicity suggests that the northern NIFZ may be approaching
failure in the culmination of a multi-century failure sequence.