An Updated Evaluation of the Rose Canyon Fault, San Diego, California

Michael J. DeFrisco

Published August 15, 2019, SCEC Contribution #9814, 2019 SCEC Annual Meeting Poster #105

The Rose Canyon Fault Zone (RCFZ) extends from La Jolla to San Diego Bay and is the southern, onshore section of the 170-km long Newport-Inglewood/Rose Canyon fault zone. The RCFZ is approximately 20 km in length and is a predominantly right-lateral strike-slip system with local reverse-oblique movement resulting in uplift of Mt Soledad, and right-normal, oblique extensional faulting responsible for the formation of San Diego Bay. Previous studies by the California Geological Survey (CGS) resulted in establishment of Alquist-Priolo Earthquake Fault Zones (APEFZs) for a portion of the fault zone from La Jolla to De Anza Cove, the Spanish Bight, Coronado, and Silver Strand faults in San Diego Bay, and the downtown graben and San Diego fault in downtown San Diego. However, evidence was insufficient to support zoning portions of the fault zone through Old Town and east of Mission Bay. We recently re-evaluated the RCFZ within the La Jolla and Point Loma 7.5’ quadrangles for the APEFZ program. Recent subsurface geologic investigations at the San Diego International Airport confirmed the northern projection of the Spanish Bight fault, and identified a previously unmapped Holocene-active fault informally named the “East Bay” fault. Paleoseismic studies (Singleton et. al., 2019) at the Presidio Hills Golf Course provide evidence for multiple late-Holocene surface rupturing events on the RCFZ in Old Town. Fault investigations downtown confirm the Holocene-active Coronado fault comes onshore at Seaport Village and suggest continuity with the “Pacific Hwy” fault, previously identified as a north-south trending pre-Holocene structure located east of Pacific Highway. Additionally, recent mapping and interpretation of fault-related geomorphic features by Kleinfelder, Inc., and the San Diego Association of Governments (SANDAG) for the Mid-Coast Corridor Transit Project provide evidence for Holocene fault activity east of Mission Bay, and suggest Holocene activity and continuity of the entire RCFZ from La Jolla to San Diego Bay. Our current evaluation considers this new data for development of updated APEFZ Special Studies Zones maps.

Citation: Singleton, D. M., T. K. Rockwell, D. Murbach, M. Murbach, J. M. Maloney, T. Freeman, and Y. Levy (2019). Late-Holocene Rupture History of the Rose Canyon Fault in Old Town, San Diego: Implications for Cascading Earthquakes on the Newport-Inglewood-Rose Canyon Fault System, Bull. Seismol. Soc. Am. 109, 855-874.

Key Words
Rose Canyon fault, Alquist-Priolo, San Diego, Coronado fault

DeFrisco, M. J. (2019, 08). An Updated Evaluation of the Rose Canyon Fault, San Diego, California. Poster Presentation at 2019 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Geology