Strike-Slip Transpressional Uplift Offshore San Onofre, California Inhibits Sediment Delivery to the Deep Sea

Wei, Emily; Holmes, J. J.; Driscoll, Neal W.

doi:10.3389/feart.2020.00051

Cited by 6 publications

(11 citation statements)

References 82 publications

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“…For cores containing more than two dates, we used these reservoirs as a parameter to generate age-depth models with the Bacon age-modeling software, version 2.3.3 (Blaauw and Christen, 2011). A more exhaustive description of measurements performed on these cores is documented by Wei et al (2019).…”

Section: Age Controlmentioning

confidence: 99%

“…Crossline 2457 (Figure 7) intersects the time-slice between two large canyons on the slope (Figure 1C). Both canyons are imaged as embayments in the time slice on Figure 6 and labeled San Onofre Canyon North and San Onofre Canyon South (labeled "SOCN" and "SOCS, " respectively, on Figure 1; Wei et al, 2019). An acoustically transparent region is observed immediately south-east of the crossline making confident interpretation difficult; however, reflector offsets in crosslines and geometry in the time slice allows for potential correlation of the fault segments between faults i and iv and that uncertainty is shown by the dashed fault trace in the region.…”

Section: Deformation and Fault Characterizationmentioning

confidence: 99%

“…The largest syncline imaged in the arbitrary line, centered around trace 2800, appears to plunge seaward with a west-southwest axis and is coincident with the San Onofre South (SOS) off-shelf drainage channel (Wei et al, 2019). A smaller syncline to the north, centered at trace 2240, also appears to plunge seaward, toward the San Onofre North (SON) drainage channel (Wei et al, 2019). Separating the two synclines is an asymmetric anticline, measuring 1686 m across at the arbitrary line in Figure 12, and narrowing to 1040 m near the shelf edge.…”

Section: Deformation and Fault Characterizationmentioning

confidence: 99%

“…The steepest slopes in the survey area are located above the basin floor at the toe of the slope and are up to 25 • . The large canyons in the northern portion of the study region (SON and SOS) incise the shelf edge (Figure 14; Wei et al, 2019).…”

Section: Deformation and Fault Characterizationmentioning

confidence: 99%

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High-Resolution 3D Seismic Imaging of Fault Interaction and Deformation Offshore San Onofre, California

2021

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The Inner California Borderland (ICB) records a middle Oligocene transition from subduction to microplate capture along the southern California and Baja coast. The closest nearshore fault system, the Newport-Inglewood/Rose Canyon (NIRC) fault complex is a dextral strike-slip system that extends primarily offshore approximately 120 km from San Diego to Newport Beach, California. Holocene slip rates along the NIRC are 1.5–2.0 mm/year in the south and 0.5 mm/year along its northern extent based on trenching and well data. High-resolution 3D seismic surveys of the NIRC fault system offshore of San Onofre were acquired to define fault interaction across a prominent strike-slip step-over. The step-over deformation results in transpression that structurally controls the width of the continental shelf in this region. Shallow coring on the shelf yields a range of sedimentation rates from 0.27–0.28 mm/year. Additionally, a series of smaller anticlines and synclines record subtle changes in fault trends along with small step-overs and secondary splay faults. Finally, sedimentary units onlapping and dammed by the anticline, place constraints on the onset of deformation of this section of the NIRC fault system. Thickness estimates and radiocarbon dating yield ages of 560,000 to 575,000 years before present for the onset of deformation.

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Section: Age Controlmentioning

confidence: 99%

Section: Deformation and Fault Characterizationmentioning

confidence: 99%

Section: Deformation and Fault Characterizationmentioning

confidence: 99%

Section: Deformation and Fault Characterizationmentioning

confidence: 99%

See 2 more Smart Citations

High-Resolution 3D Seismic Imaging of Fault Interaction and Deformation Offshore San Onofre, California

2021

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“…For cores containing more than two dates, age-depth models were generated using the Bacon age-modeling software package, version 2.3.3 (Blaauw and Christen, 2011) using these reservoirs as parameters. A more exhaustive description of measurements performed on these cores is documented by Wei et al (2020).…”

Section: Age Controlmentioning

confidence: 99%

Revealing Geometry and Fault Interaction on a Complex Structural System Based on 3D P-Cable Data: The San Mateo and San Onofre Trends, Offshore Southern California

et al. 2021

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Deformation observed along the San Mateo (SMT) and San Onofre trends (SOT) in southern California has been explained by two opposing structural models, which have very different hazard implications for the coastal region. One model predicts that the deformation is transpressional in a predominantly right lateral fault system with left lateral step-overs. Conversely in the alternative model, the deformation is predicted to be compressional associated with a regional blind thrust that reactivated detachment faults along the continental margin. State-of-the-art 3D P-Cable seismic data were acquired to characterize the geometry and linkage of faults in the SMT and SOT. The new observations provide evidence that deformation along the slope is more consistent with step-over geometry than a regional blind thrust model. For example, regions in the SOT exhibit small scale compressional structures that deflect canyons along jogs in the fault segments across the slope. The deformation observed in the SMT along northwesterly trending faults has a mounded, bulbous character in the swath bathymetry data with steep slopes ( ∼ 25°) separating the toe of the slope and the basin floor. The faulting and folding in the SMT are very localized and occur where the faults trend more northwesterly (average trend ∼ 285°) with the deformation dying away both towards the north and east. In comparison, the SOT faults trend more northerly (average trend ∼ 345°). The boundary between these fault systems is abrupt and characterized by shorter faults that appear to be recording right lateral displacement and possibly accommodating the deformation between the two larger fault systems. Onlapping undeformed turbidite layers reveal that the deformation associated with both major fault systems may be inactive and radiocarbon dating suggests deformation ceased in the middle to late Pleistocene (between 184 and 368 kyr). In summary, our preferred conceptual model for tectonic deformation along the SMT and SOT is best explained by left lateral step-overs along the predominantly right lateral strike-slip fault systems.

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

Walton,

Conrad,

Papesh

et al. 2024

Geochem Geophys Geosyst

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It is critical to characterize submarine landslide hazards near dense coastal populations, especially in areas with active faults, which can trigger slope failure, subsequent tsunamis, and damage seabed infrastructure during earthquake shaking. Offshore southern California, numerous marine geophysical surveys have been conducted over the past decade, and high‐resolution bathymetric and subsurface data now cover about 60 percent of the total region between Point Conception and the United States‐Mexico border from the California coast out to the base of Patton Escarpment ∼200 km offshore. In a comprehensive compilation and interpretive mapping effort, we find evidence of seafloor failure throughout offshore southern California with nearly 1,500 submarine landslide‐related features, including 63 discrete slide deposits with debris and >1,400 slide‐related scarps. In our analysis, we highlight new mapping of submarine landslides in Catalina Basin, the Del Mar slide, the San Gabriel slide complex, and the 232 km2 San Nicolas slide, the largest area of any known submarine landslide mass offshore southern California. Analysis of the spatial distribution of submarine landslide features suggests that most mapped slide features are located relatively near coastal sediment sources, particularly during sea‐level lowstand conditions, which underscores the importance of sediment supply and sediment accumulation on low‐gradient slopes as failure preconditioning processes. Tectonically driven uplift at shelf edges and along basin flanks is another key preconditioning factor, and our results also suggest that earthquakes along active faults trigger mass wasting, especially for repeated, small‐scale failures on tectonically steepened slopes.

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Strike-Slip Transpressional Uplift Offshore San Onofre, California Inhibits Sediment Delivery to the Deep Sea

Cited by 6 publications

References 82 publications

High-Resolution 3D Seismic Imaging of Fault Interaction and Deformation Offshore San Onofre, California

High-Resolution 3D Seismic Imaging of Fault Interaction and Deformation Offshore San Onofre, California

Revealing Geometry and Fault Interaction on a Complex Structural System Based on 3D P-Cable Data: The San Mateo and San Onofre Trends, Offshore Southern California

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

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