Geologic map and digital database of the Yucaipa 7.5' quadrangle, San Bernardino and Riverside Counties, California

Metadata Updated: November 12, 2020

The Yucaipa 7.5' quadrangle is located at the southeastern margin of the San Bernardino Basin, an extensional region situated within a right-step-over zone between the San Jacinto and San Andreas Fault zones. The quadrangle is traversed by several faults of the San Andreas system, including (from oldest to youngest) the Banning Fault and the Wilson Creek, Mission Creek, Mill Creek, and San Bernardino Strands of the San Andreas Fault. The Mill Creek Strand of the San Andreas Fault is the easternmost strand of the San Andreas in the Yucaipa quadrangle. It separates granitic and metamorphic rocks of the San Bernardino Mountains block from a thin slice of similar rocks on Yucaipa Ridge, and thus has only a small amount of strike-slip displacement. The Wilson Creek Strand traverses Yucaipa Ridge and converges toward the Mlll Creek Strand in the Santa Ana river Canyon. The fault has juxtaposed an igneous and metamorphic complex (Wilson Creek block) and overlying nonmarine sedimentary rocks (Mill Creek Formation of Gibson, 1971) against rocks of San Bernardino Mountains-type, and thus has significant strike-slip displacement. The Mission Creek Strand is inferred to lie beneath Quaternary surficial deposits along the southwestern base of the San Bernardino Mountains. This fault is the major strand of the San Andreas Fault zone, and has juxtaposed crystalline rocks of San Gabriel Mountains-type (including Pelona Schist overlain by the Vincent Thrust and associated upper-plate crystalline rocks) against the Wilson Creek block and the San Bernardino Mountains. The San Bernardino Strand defines the modern trace of the San Andreas Fault. The strand forms primary fault features in all but the youngest Quaternary surficial units, and is thought to have evolved in the last 125,000 years or so based on regional fault relations. Complications within the San Andreas Fault system over the last several hundred thousand years have created a landscape setting in which Quaternary surficial materials of the Yucaipa quadrangle have accumulated. Crustal extension throughout the San Bernardino Basin region led to uplift of the Crafton Hills block and down-dropping of the Yucaipa Valley region on faults of the Crafton Hills and Chicken Hill complex. Subsequent middle and late Quaternary streamflows deposited several generations of axial-valley and alluvial-fan sediment in the down-dropped lowlands. These deposits and the older San Timoteo beds they overlie record the history of Quaternary fault movements, and form reservoirs for ground water in the Yucaipa quadrangle. Digital Data: The geologic database of the Yucaipa 1:24,000-scale 7.5' quadrangle, San Bernardino and Riverside Counties, California, was prepared by the Southern California Areal Mapping Project (SCAMP), a regional geologic-mapping project sponsored jointly by the U.S. Geological Survey and the California Geological Survey. The database was created in ARC/INFO (Environmental Systems Research Institute, ESRI), and includes the following files: (1) a readme.txt file, (2) this metadata file, (3) coverages containing geologic data and station-location data, (4) associated INFO attribute data files, (5) a browse graphic (.pdf) of the geologic-map plot and map-marginal explanatory information, (6) a PostScript graphics file of the geologic-map plot with map-marginal explanatory information, and (7) .pdf text files describing the map units of the Yucaipa quadrangle (Description of Map Units) and their geologic age and correlation (Correlation of Map Units).

Access & Use Information

License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Date June 10, 2016
Metadata Created Date November 12, 2020
Metadata Updated Date November 12, 2020
Reference Date(s) January 1, 2003 (publication)
Frequency Of Update asNeeded

Metadata Source

Harvested from DOI Open Data

Graphic Preview

Reduced-size image of the entire map sheet, 425x300 pixels, 43k bytes. 475x334 pixels, 56k bytes.

Additional Metadata

Resource Type Dataset
Metadata Date June 10, 2016
Metadata Created Date November 12, 2020
Metadata Updated Date November 12, 2020
Reference Date(s) January 1, 2003 (publication)
Responsible Party U.S. Geological Survey, Western Region, Earth Surface Processes Team (Point of Contact)
Contact Email
Access Constraints Use Constraints: The Yucaipa 7.5' geologic-map database should be used to evaluate and understand the geologic character of the Yucaipa quadrangle as a whole. It should not be used as a detailed map for purposes of site-specific land-use planning or site-specific geologic evaluations. The database is sufficiently detailed to identify and characterize many actual and potential geologic hazards represented by faults and landslides and posed by ground subsidence and earthquake-generated ground shaking. However, it is not sufficiently detailed for site-specific determinations or evaluations of these features. Faults shown do not take the place of fault-rupture hazard zones designated by the California State Geologist (see Hart, 1988). Use of the Yucaipa geologic-map database should not violate the spatial resolution of the data. Although the digital form of the data allows the scale to be manipulated at the discretion of the user, detail and accuracy issues that are inherent to map-scale limitations similarly exist in the digital data. The fact that this database was constructed and edited at a scale of 1:24,000 means that higher-resolution data generally are not present in the dataset. Therefore, plotting at scales larger than 1:24,000 will not yield greater, real detail, although enlarged plots may reveal fine-scale (artificial) irregularities beyond the intended resolution of the database. Although higher-resolution data may be incorporated at a few places, the resolution of the entire database output is limited by the lower-resolution data. Hart, E. W., 1988, Fault-rupture zones in California; Alquist-Priolo Special Studies Zones Act of 1972 with index to special studies zones maps: California Division of Mines and Geology Special Publication 42, Access Constraints: None
Bbox East Long -116.99990817
Bbox North Lat 34.12499996
Bbox South Lat 33.99998412
Bbox West Long -117.12509183
Coupled Resource
Frequency Of Update asNeeded
Graphic Preview Description Reduced-size image of the entire map sheet, 425x300 pixels, 43k bytes. 475x334 pixels, 56k bytes.
Graphic Preview File
Graphic Preview Type GIF
Licence The U.S. Geological Survey (USGS) provides these geographic data "as is." The USGS makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. The USGS further makes no warranties, either expressed or implied as to any other matter whatsoever, including, without limitation, the condition of the product, or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although these data have been processed successfully on computers at the USGS, no warranty, expressed or implied, is made by the USGS regarding the use of these data on any other system, nor does the fact of distribution constitute or imply any such warranty. In no event shall the USGS have any liability whatsoever for payment of any consequential, incidental, indirect, special, or tort damages of any kind, including, but not limited to, any loss of profits arising out of use of or reliance on the geographic data or arising out of the delivery, installation, operation, or support by USGS. This digital, geologic map database of the Yucaipa 7.5' quadrangle, 1:24,000 map-scale, and any derivative maps thereof, is not meant to be used or displayed at any scale larger than 1:24,000 (e.g., 1:12,000).
Metadata Language
Metadata Type geospatial
Progress completed
Spatial Data Service Type
Spatial Reference System
Spatial Harvester True
Temporal Extent Begin 1930-01-01
Temporal Extent End 1998-01-01

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