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Southern California Areal Mapping Project

Geologic Framework of the San Bernardino Basin

The modern trace of the San Andreas Fault lies along the base of the San Bernardino mountains. View looking northeast toward the San Bernardino Mountains and part of the San Bernardino Basin. The modern trace of the San Andreas Fault lies along the base of the mountains. Click here for more info and enlarged image.

| Selected References |



SCAMP currently is performing geologic-mapping and geophysical investigations that will clarify the geologic setting and geologic history of the San Bernardino Basin. The goal is to describe the physical properties of rock and sediment, determine the distribution and movement history of fault systems, and provide a geologic-map basis for evaluating geologic hazards and for investigating hydrogeologic resources.


The San Bernardino Basin is the alluviated lowland that extends northwestward from Yucaipa to the Devore area at the foot of Cajon Pass. It is bounded by the San Andreas fault on the north and the San Jacinto Fault and Rialto-Colton ground-water barrier on the southwest. Current geologic understanding suggests that the lowland is a pull-apart basin that developed over the last 1.7 million years in response to a right step between the San Jacinto and San Andreas faults. This right step still is taking place today, and provides the background for current earthquake activity in the San Bernardino region. Sedimentary materials that are filling up this basin record information about interactions among the various fault systems, including their origin and movement history. The sediments also store ground water for the urbanizing San Bernardino-Fontana-Redlands-Yucaipa region.


Geologic-mapping and Geologic-framework Investigations

SCAMP currently is updating geologic-map information for the San Bernardino Basin previously released by the U.S. Geological Survey (Morton, 1978a,b,c;d; Miller, 1979; Matti and others, 1992). The updated map information will be released as digital geologic-map files. Initial releases will be the Yucaipa, Redlands, and San Bernardino South 7.5' quadrangles, followed by updates of the San Bernardino North and Devore 7.5'quadrangles; preliminary versions of these maps can be examined at the SCAMP office in the Department of Earth Sciences at U.C. Riverside.

Recent SCAMP Products

Matti, J.C., and Morton, D.M., 1993, Paleogeographic evolution of the San Andreas fault in southern California: a reconstruction based on a new cross-fault correlation, in Powell, R.E., Weldon, R.J., II, and Matti, J.C., eds., The San Andreas fault system: displacement, palinspastic reconstruction, and geologic evolution: Geological Society of America Memoir 178, p. 107-159.

Matti, J.C., Morton, D.M. and Cox, B.F., 1992, The San Andreas fault system in the vicinity of the central Transverse Ranges province, southern California: U.S. Geological Survey Open-File Report 92-354, 40 p., scale 1:250,000.

Matti, J.C., Morton, D.M., Cox, B.F., Carson, S.E., and Yetter, T.J., 1992, Geologic map of the Yucaipa 7.5' quadrangle, California: U.S. Geological Survey Open-File Report 92-446, 14 p., scale 1:24,000.

Matti, J.C., Morton, D.M., Cox, B.F., Carson, S.E., and Yetter, T.J., 2000, Geologic map and digital data base of the Yucaipa 7.5' quadrangle, San Bernardino and Riverside Counties, California: U.S. Geological Survey Open-File Report 00-XXX, scale 1:24,000 (in press).

Matti, J.C., Morton, D.M., Cox, B.F., and Kendrick, K.J., 2000, Geologic map and digital data base of the Redlands 7.5' quadrangle, Riverside and San Bernardino Counties, California, version 1.0: U.S. Geological Survey Open-File Report 2000-XXX, scale 1:24,000 (in press).

Morton, D.M., and Matti, J.C., 1993, Extension and contraction within an evolving divergent strike-slip fault complex: the San Andreas and San Jacinto fault zones at their convergence in southern California, in Powell, R.E., Weldon, R.J., and Matti, J.C., eds., The San Andreas fault system: displacement, palinspastic reconstruction, and geologic evolution: Geological Society of America Memoir 178, p. 217-230.

Morton, D.M., Matti, J.C., and Kendrick, K.J., 2000, Geologic map and digital data base of the San Bernardino South 7.5' quadrangle, San Bernardino and Riverside Counties, California, version 1.0: U.S. Geological Survey Open-File Report 2000-XXX, scale 1:24,000 (in press).

 

Geophysical Investigations

SCAMP is co-sponsoring geophysical studies of the San Bernardino Basin that will lead to a 3-D geologic/structural/physical-property model. This model will provide a basis for estimates of seismic velocity in various geologic media, which in turn will be used for earthquake ground shaking estimates, for ground-water flow modeling, and for estimates of potential for groundwater recharge. The geophysical work is closely coordinated with, and has parallel tasks in, the USGS Earthquake Hazards Program Southern California Project.

Recent SCAMP Products

Jachens, R.C., and Langenheim, V.E.,1996, Aeromagnetic map of the San Bernardino 1:100,000-scale quadrangle, California: U.S. Geological Survey Open-File Report 96-284.

Anderson, M.L., Roberts, C.W., and Jachens, R.C., 2000, Principal facts for gravity stations in the vicinity of San Bernardino, southern California, U.S. Geological Survey Open File Report 00-193, 23 p.

 


 

Cooperative Interactions

SCAMP geologic investigations in the San Bernardino Basin are coordinated with several USGS projects, and with the San Bernardino Valley Municipal Water District. These cooperative investigations include:

Geologic framework for earthquake studies:

The USGS Earthquake Hazards Program sponsors earthquake investigations in southern California, including investigations of ground-shaking potential, earthquake monitoring, and earthquake history. The California Division of Mines and Geology has a program of earthquake-fault mapping and zonation that has produced a series of fault maps for the San Bernardino Basin in response to the State of California Alquist-Priolo Earthquake Fault Zoning Act. Geologic-mapping studies by SCAMP are coordinated with these earthquake investigations, and are designed to clarify the distribution, origin, and history of faulting within the San Bernardino Basin region.

Geologic framework for ground-water studies:

The California District Office of the USGS Water Resources Division (WRD) is actively conducting ground-water investigations in the San Bernardino Basin in support of water-quality and water-supply issues. These studies include drilling investigations to obtain information about subsurface geology, ground-water flow models, and evaluations of toxic-plume migration. Ground-water investigations in the San Bernardino Basin (Bunker Hill and related ground-water basins) are conducted out of the Coastal area Program (WRD San Diego office); investigations of the Rialto-Colton Basin are conducted out of the Coastal area Program (WRD Sacramento Office). SCAMP geologic-mapping and geophysical studies are coordinated with the ground-water investigations, with the joint objective of developing a refined hydrogeologic model for the San Bernardino Basin. The hydrologic and geologic/geophysical investigations are funded cooperatively by the San Bernardino Valley Municipal Water District which maintains a Geographic Information System for the San Bernardino Basin.

Recent Cooperative Products

Frankel, Arthur, 1993, Three-dimensional simulations of ground motions in the San Bernardino Valley, California, for hypothetical earthquakes on the San Andreas fault: Bulletin of the Seismological Society of America, v. 83, p. 1020-1041.

Frankel, Arthur, 1994, Dense array recordings in the San Bernardino Valley of Landers-Big Bear aftershocks-Basin surface waves, Moho reflections, and three-dimensional simulations: Bulletin of the Seismological Society of America, v. 84, p. 613-624.

Hartzell, S., Jachens, R., Brocher, T., and Frankel, A., 1988, Imaging and ground motion in urban sedimentary basins: the Santa Clara and San Bernardino Valleys: U.S. Geological Survey Open File-Report 98-244, 28 p.

Izbicki, John A., Danskin, Wesley R. , and Mendez, Gregory O., 1998, Chemistry and isotopic composition of ground water along a section near the Newmark area, San Bernardino County, California: U.S. Geological Survey Water Resources Investigation Report 97-4179

Woolfenden, L.R., and Kadhim, Dina, 1997, Geohydrology and water chemistry in the Rialto-Colton basin, San Bernardino County, California: U.S. Geological Survey Water-Resources Investigations Report 97-4012, 101 p.


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