USGS ScienceSearch

Geology topics

Robert H. Wright

Publications and source records attributed to Robert H. Wright.

3 recordsLinked to original sources

Possible costs associated with investigating and mitigating geologic gazards in rural areas of western San Mateo County, California

This publication consists of a digital map database on a geohazards web site, http://kaibab.wr.usgs.gov/geohazweb/intro.htm, this text, and 43 digital map images available for downloading at this site. The report is stored as several digital files, in ARC export (uncompressed) format for the database, and Postscript and PDF formats for the map images. Several of the source data layers for the images have already been released in other publications by the USGS and are available for downloading on the Internet. These source layers are not included in this digital database, but rather a reference is given for the web site where the data can be found in digital format. The exported ARC coverages and grids lie in UTM zone 10 projection. The pamphlet, which only describes the content and character of the digital map database, is included as Postscript, PDF, and ASCII text files and is also available on paper as USGS Open-File Report 00-127. The full versatility of the spatial database is realized by importing the ARC export files into ARC/INFO or an equivalent GIS. Other GIS packages, including MapInfo and ARCVIEW, can also use the ARC export files. The Postscript map image can be used for viewing or plotting in computer systems with sufficient capacity, and the considerably smaller PDF image files can be viewed or plotted in full or in part from Adobe ACROBAT software running on Macintosh, PC, or UNIX platforms.

California

Preparation and use of isopleth maps of landslide deposits

Isopleth maps derived from landslide inventory maps generalize and quantify the areal distribution of landslide deposits in contour form and may be uniquely useful for some types of regional planning. The isopleth format permits incorporation of landslide information with other quantified map data in the preparation of slope stability maps. The isopleth map of landslide deposits in San Mateo County, California (scale 1:300,000), serves as an example of this technique.

California

Map showing locations of samples dated by radiocarbon methods in the San Francisco Bay region

Radiocarbon dating is an important interdisciplinary tool for studies involving events and processes during the last 40,000 years of earth history, including studies involving marine transgressions and regressions, land subsidence, climatic changes, sedimentation rates and patterns, fault movements, and archaeology, among others. The potential value of a radiocarbon date is diminished, however, if adequate site data are not taken with the sample and do not accompany the date in publication. At a minimum, published dates should include an accurate location for the dated sample, type of material dated and method of dating, nature of the site, depth below surface (or other accurately defined datum) of date sample, stratigraphy of material overlying date sample, and the significance of the data in the study.

California