|Western Earth Surface Processes Team|
Geologic Framework of the Santa Barbara Coastal Plain
The geology of the Santa Barbara coastal plain is dominated by variably
deformed Cretaceous through late Cenozoic marine and nonmarine sedimentary
strata. These strata record a long history of continental-margin sedimentation,
and deposits as young as Quaternary have sustained strong deformations
that include folding, thrust and reverse faulting, and rotations of
crustal blocks about steep axes. Quaternary deformation in this area
has produced a series of uplifted and folded coastal terraces and
alluvial fans that form a substrate for the rapidly growing Santa
Barbara-Goleta urban corridor.
Click here to see additional geologic maps and information on the region.
The Santa Barbara coastal plain is transected by numerous active and potentially active folds and partly blind reverse faults of the Santa Barbara fold and fault belt (Fig. 2). Strong earthquakes that occurred in the region in 1925 (M 6.8) and 1978 (M 5.1) are evidence that such structures pose a significant earthquake hazard to the 200,000 people living on the coastal plain. Young landslide deposits along the steep lower flank of the Santa Ynez Mountains indicate that slope failures and mass movements have, and may continue to, threaten urbanized parts of the coastal plain. In addition, the coastal plain is subjected to limited groundwater resources and poor water quality due to salt-water contamination.
Submarine landslides have also been recognized offshore in the Santa Barbara Channel and are considered a potential source of local tsunami activity along the Santa Barbara coast.
See additional information about the Transverse Ranges Region:
Geology of the Inland Empire (includes information about the San Andreas Fault and other fault systems)
San Gabriel Mountains
San Gorgorio Pass Region
San Bernardino Mountains
Return to the Geology of the Transverse Ranges