Identification_Information: Citation: Citation_Information: Originator: M.L. Anderson, C.W. Roberts, and R.C. Jachens Publication_Date: 2000 Title: Principal Facts for Gravity Stations in the Vicinity of San Bernardino, Southern California Edition: rev 1.0 Publication_Information: Publication_Place: U.S. Geological Survey, Menlo Park, CA Publisher: U.S. Geological Survey Online_Linkage: http://wrgis.wr.usgs.gov/open-file/of00-193 Description: Abstract: New gravity measurements in the vicinity of San Bernardino, California were collected to help define the characteristics of the Rialto-Colton fault. The data were processed using standard reduction formulas and parameters. Rock properties such as lithology, magnetic susceptibility and density also were measured at several locations. Purpose: To provide basic geophysical information to local hydrologic studies Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Megan L. Anderson Contact_Organization: U.S. Geological Survey Contact_Address: Address: 345 Middlefield Rd. MS 989 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: 650-329-5308 Contact_Electronic_Mail_Address: mlanderson@usgs.gov Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -117.625 East_Bounding_Coordinate: -117.0 North_Bounding_Coordinate: 34.25 South_Bounding_Coordinate: 34.0 Native_Data_Set_Environment: Data was stored and analysed on a SUN Ultra4000 UNIX platform Status: Progress: Preliminary report Keywords: Place: Place_Keyword: Southern California, San Bernardino, San Bernardino basin Theme: Theme_Keyword: gravity, density, isostatic anomaly, magnetic property, San Jacinto fault zone Access_Constraints: none Use_Constraints: none Data_Quality_Information: Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Accuracy of the point data is roughly 10m. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Accuracy of the point data is roughly 5-10cm. Attribute_Accuracy: Attribute_Accuracy_Report: Observed gravity data are accurate to 0.05 mGal; reduced anomalies are accurate to 1-2 mGal. Data are more accurate in the flat areas than in the mountains because of uncertainties in the terrain correction. Terrain corrections are accurate to 0.2 mGal in the flat areas and to 0.4-1.5 mGal in the mountains. Grain density measurements are accurate to 0.01 g/cm3; susceptibility measurements to 0.01 x 10-3 cgs units. Logical_Consistency_Report: see open-file report Completeness_Report: Dataset based on geophysical analysis. See open-file report. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Tang, R.W., and Ponce, D.A. Publication_Date: 1982 Title: Principal facts, accuracies, sources, and base station descriptions for 4915 gravity stations on the San Bernardino 1 degrees x 2 degrees quadrangle, California Series_Information: Series_Name: U.S. Geological Survey Open-File Report 82-004 Citation_Information: Originator: Sikora, R.F., Langenheim, V.E., Biehler, Shawn, Beyer, L.A., and Chapman, R.H. Publication_Date: 1993 Title: Principal facts and base station descriptions for gravity data compiled for the Santa Ana 1 degrees by 2 degrees quadrangle, California Series_Information: Series_Name: U.S. Geological Survey Open-File Reports 93-217A and 93-217B Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geodetic_Model: Horizontal_Datum_Name: Geographic North American Datum 1927 Ellipsoid_Name: CLARKE 1866 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: North American Vertical Datum 1929 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Definition: Point_Type Overview_Description: Entity_and_Attribute_Overview: The data files are in ASCII format. The gravity data define point data with information as follows: STATION NAME (a8): An alphanumeric combination of up to 8 characters used for station identification; LAT (f3.0,f6.3): Latitude in degrees and minutes, to 0.01 minute; LON (f4.0,f6.3): Longitude in degrees and minutes, to 0.01 minute; ELEV (f8.2): Elevation, to 0.1 ft; OG (f10.3): Observed gravity, to 0.01 mGal; FAA (f9.3): Free-air anomaly to 0.01 mGal; SBA (f8.3): Simple Bouguer anomaly to 0.01 mGal; ITC (f7.3): Inner terrain correction for a denisty fo 2.67 g/cm3, to 0.01 mGal, followed by a letter denoting the extent of the correction. "Z" indicates computer terrain correction from the station out to 166.7 km with inner terrain correction out to D zone; TC (f7.3): Total terrain correction from the station to 166.7 km for a density of 2.67 g/cm3, to 0.01 mGal; TC CODE (a1): Letter denoting the extent of the correction, according to the Hayford-Bowie template (e.g. 'D' means 590 m); CBA (f8.3): Complete Bouguer anomaly reduced for a density of 2.67 g/cm3, to 0.01 mGal; ISO (f8.3): Isostatic residual anomaly values assuming an Airy model for isostatic compensation of topographic loads. This model assumes a crustal thick ness of 25 km, a topographic load density of 2.67 g/cm3, and a density contrast across the base of the model crust of 0.4 g/cm3; The density and susceptibility data define point data with information as follows: STATION NAME (a8): An alphanumeric combination of up to 8 characters used for station identification; LAT (f3.0,f6.3): Latitude in degrees and minutes, to 0.01 minute; LON (f4.0,f6.3): Longitude in degrees and minutes, to 0.01 minute; GRAIN DENSITY (f7.2): in grams per cubic centimeter; SATURATED BULK DENSITY (f6.2): in grams per cubic centimeter; DRY BULK DENSITY (f6.2): in grams per cubic centimeter; MAGNETIC SUSCEPTIBILITY (f7.2): in 10-3 cgs units; GEOLOGIC MAP UNIT (a10): An alphanumeric combination of up to 10 characters for corresponding geologic map unit when plotted on the 1:24,000 geologic map, see open-file report for map references; ROCK TYPE (a32): description of hand sample. Metadata_Reference_Information: Metadata_Date: 20000516 Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata