Possible Costs Associated with Investigating and Mitigating Some Geologic Hazards in Rural Parts of San Mateo County, California

These susceptibility maps and the cost assessment data allow landowners in
rural western San Mateo County to determine if their property is impacted by
deep-seated landslide and debris flow hazards and, if so, how much money might
be required to investigate them. The information is also useful for land use
planners, local officials and public interest groups. For example, the maps
will be useful for purposes such as determining where sediment from landslides
might adversely affect fish in the various creeks, or where roads might be
closed after heavy rainfall.

This publication addresses deep-seated landslide susceptibility, debris flow
susceptibility, and other geologic hazards in rural parts of western San Mateo
County. The report also estimates possible costs of investigating and
mitigating the landslide hazards. The study area includes the Half Moon Bay
7.5' quadrangle, the Montara Mountain 7.5' quadrangle, and the Pescadero/Butano
Creeks watershed. Hazard maps were derived by integrating slope data and
previous geologic, landslide and debris flow mapping. The digital database,
which is found at &http://geopubs.wr.usgs.gov/open-file/of00-127& includes 43
plotfiles for slope maps, Digital Orthophoto Quadrangle maps, Digital Raster
Graphic topographic base maps, geologic maps, deep-seated landslide inventory
maps, deep-seated landslide susceptibility maps, and debris flow inventory and
susceptibility maps. Twelve ARC export files of supporting digital data are
included in the database, and other data have been published previously and are
available at other USGS websites named in an accompanying pamphlet (of00-127_2.
ps, of00-127_2.pdf, of00-127_2.txt).

As explained in the pamphlet, a geohazard website included in the publication
facilitates interactive use of the hazard information in this database. All
data layers are in Universal Transverse Mercator (UTM) projection, zone 10.
The scale of the source maps limits the spatial resolution (scale) of the
database to 1:24,000.

An explanatory pamphlet (of00-127_2.ps, of00-127_2.pdf, of00-127_2.txt)
accompanies the digital database. An interactive website for landslide hazards
http://landslides.usgs.gov/ is provided for the study area. People
can use the website to locate their property, overlay deep-seated landslide
hazard maps and determine the possible costs associated with investigating
them. Information is provided for investigating and mitigating several other
kinds of geologic hazards, but the data are not interactive.