Paleoseismicity Of the North Branch Of the Newport-Inglewood Fault Zone In Huntington Beach, California, From Cone Penetrometer Test Data

Authors

Lisa B. Grant, Chapman University
John T. Waggoner, Southern California Earthquake Center
Thomas K. Rockwell, Southern California Earthquake Center
Carmen von Stein, Southern California Earthquake Center

Document Type

Article

Publication Date

1997

Abstract

Application of cone penetrometer testing (CPT) is a promising method for studying subsurface fault zones in stratified, unconsolidated sediment where trenching is not feasible. Analysis of data from 72 CPTs, spaced 7.5 to 30.0 m apart, and 9 borings indicates that the North Branch fault, the active strand of the Newport-Inglewood fault zone (NIFZ) in Huntington Beach, has generated at least three and most likely five recognizable surface ruptures in the past 11.7 +/- 0.7 ka. Additional smaller earthquakes similar to the M-w 6.4 1933. Long Beach earthquake may also have occurred but would not be recognizable with this method. The minimum right-lateral Holocene slip rate of the NIFZ in the study area is estimated to be 0.34 to 0.55 mm/yr. The actual slip rate may be significantly higher.

Comments

This article was originally published in Bulletin of the Seismological Society of America, volume 87, issue 2, in 1997.