Geologic map and digital database of the San Rafael Mtn. 7.5- minute Quadrangle, Santa Barbara County, California, USGS OFR 01-290

This database and accompanying plot files depict the distribution of geologic
materials and structures at a regional (1:24,000) scale. The report is
intended to provide geologic information for the regional study of materials
properties, earthquake shaking, landslide potential, mineral hazards, mineral
and energy resources, seismic velocity, and earthquake faults. In addition,
the report contains new information and interpretations about the regional
geologic history and framework. However, the regional scale of this report
does not provide sufficient detail for site development purposes. In addition,
this map does not take the place of fault-rupture hazard zones designated by
the California State Geologist (Hart and Bryant, 1997). Similarly, the database
cannot be substituted for comprehensive maps that systematically identify and
classify landslide hazards.

This digital map database, compiled from previously published and unpublished
data, and new mapping by the authors, represents the general distribution of
bedrock and surficial deposits in the mapped area. Together with the
accompanying text file (srm_expl.txt, srm_expl.pdf), it provides current
information on the geologic structure and stratigraphy of the area covered.
The database delineates map units that are identified by general age and
lithology following the stratigraphic nomenclature of the U.S. Geological
Survey. The scale of the source maps limits the spatial resolution (scale) of
the database to 1:24,000 or smaller.

The databases in this report were compiled in ARC/INFO, a commercial Geographic
Information System (Environmental Systems Research Institute, Redlands,
California), with version 3.0 of the menu interface ALACARTE (Fitzgibbon and
Wentworth, 1991, Fitzgibbon, 1991, Wentworth and Fitzgibbon, 1991). The files
are COVERAGE (ARC/INFO vector data) format. Coverages are stored in
uncompressed ARC export format (ARC/INFO version 8.0. 2). ARC/INFO export
files (files with the .e00 extension) can be converted into ARC/INFO coverages
in ARC/INFO (see below) and can be read by some other Geographic Information
Systems, such as MapInfo via ArcLink and ESRI's ArcView (version 1.0 for
Windows 3.1 to 3.11 is available for free from ESRI's web site:
http://www.esri.com.) The digital compilation was done in version 7.2.1 of
ARC/INFO with version 3.0 of the menu interface ALACARTE (Fitzgibbon and
Wentworth, 1991, Fitzgibbon, 1991, Wentworth and Fitzgibbon, 1991). The
geologic map information was digitized from stable originals of the geologic
maps at 1:24,000 scale. The author manuscripts (pen on mylar) were scanned
using a Altek monochrome scanner with a resolution of 800 dots per inch. The
scanned images were vectorized and transformed from scanner coordinates to
projection coordinates with digital tics placed by hand at quadrangle corners.
The scanned lines were edited interactively by hand using ALACARTE, color
boundaries were tagged as appropriate, and some scanning artifacts visible at
1:24,000 were removed.

This report consists of a set of geologic map database files (Arc/Info
coverages) and supporting text and plotfiles. In addition, the report includes
two sets of plotfiles (PostScript and PDF format) that will generate map sheets
and pamphlets similar to a traditional USGS Open-File Report. These files are
described in the explanatory pamphlets (srm.ps, srm.pdf, and srm.txt). The
base map layers used in the preparation of the geologic map plotfiles were
scanned from a scale-stable version of the USGS 1:24,000 topographic maps of
the San Rafael Mtn. (1959, photorevised 1988) 7.5-minute quadrangle. The map
has a 40 foot contour interval.