Morphology, structure, and kinematics of the San Clemente and Catalina faults based on high-resolution marine geophysical data, southern California Inner Continental Borderland (USA)

Abstract

<jats:p>Catalina Basin, located within the southern California Inner Continental Borderland (ICB), United States, is traversed by two active submerged fault systems that are part of the broader North America–Pacific plate boundary: the San Clemente fault (along with a prominent splay, the Kimki fault) and the Catalina fault. Previous studies have suggested that the San Clemente fault (SCF) may be accommodating up to half of the ~8 mm/yr right-lateral slip distributed across the ICB between San Clemente Island and the mainland coast, and that the Catalina fault (CF) acts as a significant restraining bend in the larger transform system. Here, we provide new high-resolution geophysical constraints on the seabed morphology, deformation history, and kinematics of the active faults in and on the margins of Catalina Basin. We significantly revise SCF mapping and describe a discrete releasing bend that corresponds with lows in gravity and magnetic anomalies, as well as a connection between the SCF and the Santa Cruz fault to the north. Subsurface seismic-reflection data show evidence for a vertical SCF with significant lateral offsets, while the CF exhibits lesser cumulative deformation with a vertical component indicated by folding adjacent to the CF. Geodetic data are consistent with SCF right-lateral slip rates as high as ~3.6 mm/yr and transpressional convergence of &amp;lt;1.5 mm/yr accommodated along the CF. The Quaternary strands of the SCF and CF consistently cut across Miocene and Pliocene structures, suggesting generation of basin and ridge morphology in a previous tectonic environment that has been overprinted by Quaternary transpression. Some inherited crustal fabrics, especially thinned crust and localized, relatively hard crustal blocks, appear to have had a strong influence on the geometry of the main trace of the SCF, whereas inherited faults and other structures (e.g., the Catalina Ridge) appear to have minimal influence on the geometry of active faults in the ICB.</jats:p>

Recency of Faulting and Subsurface Architecture of the San Diego Bay Pull-Apart Basin, California, USA

“…The misaligned magnetic anomalies and variations in along strike character of batholiths in the Peninsular Ranges point towards the region occupied by the transpeninsular faults (i.e., the Agua Blanca and San Miguel-Vallecitos), potentially developing above pre-existing crustal weaknesses that represent a more mechanically favorable path in response to regional strains. Similar arguments have been invoked to explain fault development in general as well as other areas of the Big Bend Domain (Langenheim et al, 2004, Cooke et al, 2013Walton et al, 2020b).…”

A Comprehensive Assessment of Submarine Landslides and Mass Wasting Processes Offshore Southern California

“…Catalina Basin, located in the Inner Borderland (Figure 1), contains three total discrete slides, two of which are significant failures in the northeastern part of the basin first documented by Walton, Brothers, et al. (2020) (Figure 4). The slides are located at just under 1,000 m water depth and downslope of the shelf break offshore of northwestern Santa Catalina Island along the south‐facing slope of Catalina Ridge (Figure 4a).…”

“…The two discrete slides each have arcuate, connected headwall and sidewall scarps (relief of up to ∼40 m) located on an open slope area dipping at approximately 8–12° in the headwall region (Figure 4a). Both slides appear to be translational with SW‐trending lobate debris aprons; the debris apron for the larger southern slide has a runout of ∼7 km and appears to terminate at the ∼5‐m‐relief Catalina fault (Walton, Brothers, et al., 2020; Figure 4a). The nearest land is Santa Catalina Island, and the closest shoreline to the slide headwalls is 6–8 km away.…”

“…For example, the Santa Cruz Canyon captures coarse‐grained terrigenous sediment sourced from Santa Cruz and Santa Rosa Islands, which is transported downslope to a ∼30 km 2 distributary fan and channel system on the basin floor (Barnes, 1970; Felsher, 1971; Schwalbach et al., 1996). Similarly, Catalina Canyon funnels terrigenous sediment from Santa Catalina Island to the floor of the Catalina Basin (Walton, Brothers, et al., 2020). Sedimentation rates and sources are variable along the coast (e.g., Warrick & Farnsworth, 2009), generally highest in Santa Barbara Basin and lower southward into the Gulf of Santa Catalina.…”

“…Numerous studies assessing offshore Quaternary fault slip rates, offset, geometry, and seismic activity have been conducted over the past several decades. Detailed studies exist along the Newport‐Inglewood‐Rose Canyon fault (e.g., Sahakian et al., 2017; Singleton et al., 2021), the Carlsbad/San Onofre/San Mateo fault zone (Conrad et al., 2019; Holmes et al., 2021; Wei et al., 2020), the Palos Verdes fault (e.g., Alongi et al., 2022; Brothers et al., 2015) the San Diego Trough fault (e.g., H. F. Ryan et al., 2012), and the San Clemente fault (e.g., Walton, Brothers, et al., 2020), amongst others (e.g., Astiz & Shearer, 2000; Chaytor et al., 2008; Fisher et al., 2004; Lee et al., 2009; Legg et al., 2007, 2015; Lindvall and Rockwell, 1995; Pinter & Sorlien, 1991; H. F. Ryan et al., 2009; Seeber & Sorlien, 2000; Shaw & Suppe, 1996). Most of the documented Quaternary faults are considered to be seismically active today (e.g., Walton, Papesh, et al., 2020 data compilation).…”