Search for geospatial/GIS data

Find GIS data held at MIT and other institutions

10,000+ results returned

  1. Title: Mining Districts, Victoria, Australia, ca. 1868 (Raster Image)

    Contributors:

    Summary: This layer is a georeferenced raster image of the historic paper map entitled: Victoria mining districts, mining divisions & the gold fields, engraved by William Slight under the direction of R. Brough Smyth ; colored by Arthur Everett, August 1st, 1868. It was published by Dept of Mines ca. 1868. Scale [ca. 1:1,000,000].The image inside the map neatline is georeferenced to the surface of the earth and fit to the coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, administrative boundaries, railroads, gold reefs, mining districts, telegraph lines, shoreline features, and more. Relief shown by hachures. Includes notes.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

    View full record

  2. Title: Rome, Italy, 1862 (Raster Image)

    Contributors:

    Summary: This layer is a georeferenced raster image of the historic paper map entitled: Pianta di Roma, Giovanni Montiroli inv. e dis. le vedute; Augusto Fornari incise; Domenico Feltrini scrisse. It was published by Luigi Piale in nell' anno MDCCCLXII [i.e., 1862]. Scale [ca. 1:8,500,000]. Covers Rome, Italy and Vatican City. The image inside the map neatline is georeferenced to the surface of the earth and fit to the 'European Datum 1950 UTM Zone 33N' coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, city districts, walls, gates, and fortifications, selected buildings, and more. Relief is shown by hachures. Includes indices and inset: Controni di Roma.This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

    View full record

  3. Title: Part of Thunder Bay district : traversed by the Canadian Northern Railway

    Contributors:

    Summary: Surveys and geology by A.G. Burrows, 1916.; Relief shown by hachures and spot heights. 52 x 73 centimeters Scale 1:126,720; 1 inch = 2 miles General Map Collection

    View full record

  4. Title: Map of Northern Ontario : showing the northern part of the Nipissing Algoma and Thunder Bay

    Contributors:

    Summary: Shows administrative districts, mining districts, bodies of water, railroads, and textual descriptions of topography and ground cover.; "J.F. Whitson, O.L.S."--lower left.; "Compiled from surveys & explorations by the Department of Crown Lands and surveys by the Geological Department of Canada"--below title.; "E.H. Harcourt Co. Limited. Litho. Toronto." 146 x 181 centimeters, sheets 79 x 112 centimeters. or smaller Scale [1:506,880] 1 inch = 8 miles General Map Collection

    View full record

  5. Title: Map of North Western Ontario : shewing [sic] the districts of Kenora, Rainy River, Thunder Bay, and part of Algoma

    Contributors:

    Summary: Depths shown by isolines.; "E.H. Harcourt Co. Limited. Litho. Toronto."; "Mining divisions bounded by red lines..." ; names of divisions also indicated in red. 88 x 200 centimeters, sheets 92 x 117 centimeters and 92 x 92 centimeters Scale [1:506,880] 1 inch = 8 miles General Map Collection

    View full record

  6. Title: Map of the state of Colorado showing the coal and metalliferous areas

    Contributors:

    Summary: Includes 3 insets. 73 x 85 centimeters Scale [1:760,320] 1 inch = 12 miles General Map Collection

    View full record

  7. Title: Map of northern parts of the districts of Algoma and Nipissing, province of Ontario

    Contributors:

    Summary: To accompany report of J. M. Bell, 13th report Bureau of Mines, 1904.; Shows locations for gypsum, iron, and lignite. 46 x 66 centimeters Scale [1:506,880] 1 inch = 8 miles General Map Collection

    View full record

  8. Title: Relative Landslide Potential, Elk River Watershed, California, 1940-2000

    Contributors:

    Summary: This raster dataset represeting relative landslide potential within the Elk River watershed in Humboldt County, California. This layer contains five categories used to indicate potential for landsliding 91 = very low, 5 = very high). This dataset is the product of the Department of Conservation, California Geological Survey’s (CGS) investigation of landslides in the Elk River watershed. The 52 square mile study area is located in Humboldt County in northwestern California. The investigation was based on interpretation of 1940, 1941, 1948, 1954, 1962, 1965, 1984, 1988, 1996 and 2000 aerial photos, findings from CGS’s landslide mapping conducted in the early 1980s (Kilbourne, R.T. 1982-84, Manson, M. W. 1984), as well as other sources. Mapping was conducted at 1:24,000 scale. The resulting maps are titled “Geologic and Geomorphic Features Related to Landsliding, Elk River Watershed” (Plate 1) and “Relative Landslide Potential with Geologic and Geomorphic Features, Elk River Watershed” map (Plate 2). This study was conducted at a regional scale of mapping using ten sets of aerial photos combined with a compilation of earlier published and unpublished work. Other photo sets may reveal additional landslides. The regional nature of the study makes the data and maps, including the relative landslide potential zones, inappropriate as a substitute for site-specific analysis. CGS evaluated the geology, relative slope stability and geomorphic characteristics within the watershed, and compiled the digital geospatial data described in this document. This mapping and compilation is geared toward providing baseline geologic and geomorphic data to aid in responsible land management, as well as the development of watershed restoration projects, watershed management strategies, and watershed plans. Initial checking of attributes was conducted by the geologists who mapped the features. Limited field assessment of attributes was completed. The 'confidence' attribute indicates the geologist's level of certainty in a given feature (typically as viewed through a stereoscope). Peer reviewers and GIS staff conducted additional quality control. Because the attribute fields are designed to address various types of mapping products, and because some data is compiled from other sources, not all attribute fields are populated. Marshall, G., Mendes, E., California Geological Survey and California Dept. of Conservation. (2005). Relative Landslide Potential, Elk River Watershed, California, 1940-2000 California Geological Survey. Available at: http://purl.stanford.edu/tv351wx8553. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  9. Title: Planimetric Features - Curbs, Islands within Right of Way

    Contributors:

    Summary: Curbs and islands within the city rights-of-way. The data was develped by merging the 73 individual feature files of the Basemap into one citywide map. While the individual features files have not been updated since their development, the citywide file was updated to reflect changes along the Embarcardero corridor and along King St. Please note that the sidewalk widths (curbs) were derived from project working drawings and may not be as-builts conditions. There are plans by DPW to update the layers found in the features drawings.

    View full record

  10. Title: Orthophoto Grid

    Contributors:

    Summary: This data set is a grid of San Francisco and Treasure Island that references the appropriate TileKey Image and Quadrant for the Orthophotos.

    View full record

  11. Title: Supervisor Districts

    Contributors:

    Summary: Supervisorial districts for the City of San Francisco. This data include Treasure Island as part of Supervisor District 6. The data was created based on legal description as found in the City Charter.

    View full record

  12. Title: MassGIS 2003 Massachusetts Schools (May 2002)

    Contributors:

    Summary: This datalayer shows the location of 1,898 public and 623 private schools, pre-school through high school, in Massachusetts. This data was developed by the Massachusetts Department of Environmental Protection's (DEP) GIS Program based on database information provided by the Massachusetts Department of Education (DOE).

    View full record

  13. Title: Relative Landslide Potential Matrix: Albion River Watershed, California, 1984-2002

    Contributors:

    Summary: This raster layer represents relative landslide potentials within the Albion River watershed in Mendocino County, California. These data were generated using a landslide potential matrix prepared by geologists familiar with the study area. The matrix is based on landslide feature type and activity, geomorphic features, geology, and slope found within the watershed. The matrix is included in the data dictionary with the relative landslide potential layer information. This mapping began as part of the North Coast Watershed Assessment Program (NCWAP) which was de-funded by the Legislature in June 2003, the work was subsequently completed in late 2003 and early 2004. The California Geological Survey (CGS) evaluated the geology, fluvial geomorphic characteristics, relative slope stability and geomorphic characteristics within the watershed, and compiled the digital geospatial data described in this document. This mapping and compilation is geared toward providing baseline geologic and geomorphic data to aid in responsible land management, as well as the development of watershed restoration projects, watershed management strategies, and watershed plans. California. Division of Mines and Geology. (2004). Relative Landslide Potential Matrix: Albion River Watershed, California, 1984-2002. California Division of Mines and Geology. Available at: http://purl.stanford.edu/sd935db0706 The Albion River watershed is predominantly located on the coastal side of the Mendocino Range, the western-most range of the northern California Coast Ranges Geomorphic Province. The Albion River drains 43 square miles of the Mendocino County coastline. The headwaters are approximately 12 miles inland. The data is a product of the Department of Conservation, California Geological Survey’s (CGS) investigation of landslides and fluvial geomorphology of the Albion River watershed. The investigation was based on interpretation of 1984 and 2000 aerial photos, findings from CGS’s landslide mapping conducted in the early 1980s (Kilbourne, R.T. 1982-84, Manson, M. W. 1984), as well as other sources (McLaughlin, 1997 and Matthews, 2001). Link to this dataset on the California Department of Conservation website as of November 2014: http://www.conservation.ca.gov/cgs/fwgp/Pages/albion.aspx This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  14. Title: 10-Meter Digital Elevation Model: Albion River Watershed, California, 1984-2002

    Contributors:

    Summary: This raster layer is a 10-meter resolution digital elevation model (DEM) depicting the terrain surface and elevations within the Albion River watershed. These data were generated from 7.5-minute topographic quadrangle maps by the US Geological Survey. This mapping began as part of the North Coast Watershed Assessment Program (NCWAP) which was de-funded by the Legislature in June 2003, the work was subsequently completed in late 2003 and early 2004. The California Geological Survey (CGS) evaluated the geology, fluvial geomorphic characteristics, relative slope stability and geomorphic characteristics within the watershed, and compiled the digital geospatial data described in this document. This mapping and compilation is geared toward providing baseline geologic and geomorphic data to aid in responsible land management, as well as the development of watershed restoration projects, watershed management strategies, and watershed plans. California. Division of Mines and Geology. (2004). 10-Meter Digital Elevation Model: Albion River Watershed, California, 1984-2002. California Division of Mines and Geology. Available at: http://purl.stanford.edu/jg941rj5247 The Albion River watershed is predominantly located on the coastal side of the Mendocino Range, the western-most range of the northern California Coast Ranges Geomorphic Province. The Albion River drains 43 square miles of the Mendocino County coastline. The headwaters are approximately 12 miles inland. The data is a product of the Department of Conservation, California Geological Survey’s (CGS) investigation of landslides and fluvial geomorphology of the Albion River watershed. The investigation was based on interpretation of 1984 and 2000 aerial photos, findings from CGS’s landslide mapping conducted in the early 1980s (Kilbourne, R.T. 1982-84, Manson, M. W. 1984), as well as other sources (McLaughlin, 1997 and Matthews, 2001). Link to this dataset on the California Department of Conservation website as of November 2014: http://www.conservation.ca.gov/cgs/fwgp/Pages/albion.aspx This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  15. Title: 10-Meter Hillshade Grid: Albion River Watershed, California, 2004

    Contributors:

    Summary: This shaded relief map was derived from the digital elevation model (see "Digital Elevation Model: Albion River Watershed, California, 2004" raster file) file to more accurately depict landscape within the Albion River watershed predominantly located on the coastal side of the Mendocino Range, the western-most range of the northern California Coast Ranges Geomorphic Province. The Albion River drains 43 square miles of the Mendocino County coastline. The headwaters are approximately 12 miles inland. Data portrays landslides, geomorphic features related to landsliding, relative landslide potential, geology, and stream channel geomorphic conditions. The data is a product of the Department of Conservation, California Geological Survey’s (CGS) investigation of landslides and fluvial geomorphology of the Albion River watershed. The investigation was based on interpretation of 1984 and 2000 aerial photos, findings from CGS’s landslide mapping conducted in the early 1980s (Kilbourne, R.T. 1982-84, Manson, M. W. 1984), as well as other sources (McLaughlin, 1997 and Matthews, 2001). This mapping began as part of the North Coast Watershed Assessment Program (NCWAP) which was de-funded by the Legislature in June 2003, the work was subsequently completed in late 2003 and early 2004. The California Geological Survey (CGS) evaluated the geology, fluvial geomorphic characteristics, relative slope stability and geomorphic characteristics within the watershed, and compiled the digital geospatial data described in this document. This mapping and compilation is geared toward providing baseline geologic and geomorphic data to aid in responsible land management, as well as the development of watershed restoration projects, watershed management strategies, and watershed plans. The Albion River watershed is predominantly located on the coastal side of the Mendocino Range, the western-most range of the northern California Coast Ranges Geomorphic Province. The Albion River drains 43 square miles of the Mendocino County coastline. The headwaters are approximately 12 miles inland. The data is a product of the Department of Conservation, California Geological Survey’s (CGS) investigation of landslides and fluvial geomorphology of the Albion River watershed. The investigation was based on interpretation of 1984 and 2000 aerial photos, findings from CGS’s landslide mapping conducted in the early 1980s (Kilbourne, R.T. 1982-84, Manson, M. W. 1984), as well as other sources (McLaughlin, 1997 and Matthews, 2001). Link to this dataset on the California Department of Conservation website as of November 2014: http://www.conservation.ca.gov/cgs/fwgp/Pages/albion.aspx

    View full record

  16. Title: Landslide Activity, Freshwater Creek Watershed, California, 1942-1999

    Contributors:

    Summary: This point shapefile depicts landslide activity within the Freshwater Creek watershed in Humboldt County, California between 1942 and 1999 at 1:24,000 scale. These data were derived from digital maps of landslide potential and geologic features in Humboldt County originally published in 1999 by the California Division of Mines and Geology (OFR 99-10 and OFR 99-10a). The data for the original mapping were compiled from multiple sources including published maps and reports, aerial photograph mapping, and reconnaissance geologic mapping. The maps/data are useful in preparation of Timber Harvesting Plans, and for use by land managers for identifying areas of potentially unstable ground. The maps/data serve as a guide to potential problem areas where more site-specific review is required. California Division of Mines and Geology and California Geological Survey. (2002). Landslide Activity, Freshwater Creek Watershed, California, 1942-1999. California Dept. of Conservation and California Geological Survey. Available at http://purl.stanford.edu/xb539vj7108. The discussion below was excerpted from OFR 99-10 and 99-10a. The geology of the drainage is dominated by the Freshwater Fault. This fault is considered a normal fault with blocks on either side stepping down to the west in a regional context. Multiple strands of the fault appear to be present in the study area. The fault is considered inactive because no evidence of movement after late Quaternary time has been observed along it. The Freshwater Fault splits the watershed into two sections having different geologic conditions, topographic styles and potentials for landsliding (Plate 1). Much of the western half of the drainage has relatively steep topography underlain by gently dipping, interbedded mudstone, siltstone, sandstone and minor conglomerate of the Wildcat Group (early Pleistocene to late Miocene). These rocks are typically prone to shallow debris flows/slides and occasional translational/rotational rock slides. The Wildcat Group in this part of the drainage rests uncomformably atop interbedded sandstone and shale of the Yager Formation (early Tertiary). The Yager Formation dips steeply to the northwest (Plate 1). Only one translational/rotational rockslide was identified in this unit. Several lineaments were noted on the aerial photographs throughout this part of the drainage, but no faults are indicated. The geology of the eastern half of the drainage is complex and most of the larger translational/rotational landslides and earthflows are found there. The western third of this area is underlain by Wildcat Group rocks that rest unconformably atop dense sandstones and shales of the Yager Formation and Coastal Belt of the Franciscan Assemblage (PLATE 1). The contacts between Yager and Franciscan rocks probably represent multiple strands of the Freshwater Fault (Keith Knudsen, May 1999, personal communication). The remainder of the eastern half is dominated by a series of northeast-dipping thrust faults. These faults are considered inactive at this time because they are not indicated on the State of California Earthquake Fault Zone map (State of California, 1983). The thrust faults juxtapose irregular slabs of dense sandstone/shale and melange of the Coastal Belt of the Franciscan Assemblage. The erosional contrast between the two units is seen as discrete bands of "hard" and "soft" topography that cut through the drainage in a north-westerly direction (Plate 1). The characteristics and properties of the various rock units found in this area were taken into account during the assessment of relative landslide potential. The primary sources of geological data used in preparing the relative landslide potential map are compiled on Plate 1 of Open-File Report 99-10. The Relative Landslide Potential Map has been prepared to aid in resource management and general land-use planning. It is not intended, nor should it be used for, evaluation of specific sites. Site specific evaluations often require detailed engineering geologic studies and soil engineering investigations of the underlying soil and bedrock for proper planning of specific projects. This map is derivative, based on the following: 1) the occurrence and distribution landslides, other types of slope failure, and features indicating slope instability (Plate 1, Open-File Report 99-10); 2) the geology of the area, including bedrock types and lithologic properties relative to slope stability and distribution of various earth materials, as well as the structural framework, such as the folded and faulted strata found throught the region; and 3) the relative behavior of slopes within the area as interpreted from analysis of historic aerial photographs and recent field observations. Studies of the stability of specific sites commonly require development of quantitative data through laboratory testing of field samples. This level of testing was not done for this regional evaluation. In producing this map, it was assumed that actively sliding material has the lowest relative strength, and thus, the highest relative potential for landsliding of all the geological materials underlying the slopes. Recent alluvial deposits in the valley bottom were assumed to possess the least potential for landsliding due to their flat slope. The relative potential for landsliding between these extremes was evaluated subjectively based on aerial photograph interpretation, field observations and the following principal factors: The broad apparent stability characteristics of geological materials underlying the slopes and adjacent lower-lying areas, as expressed in their natural exposures and their observed responses to alteration by land-use activities. For example, slopes that exhibit abundant evidence of landsliding or downslope creep of the soil are considered oversteepened relative to the strength of the materials that underlie them. Steepness of slopes, whether or not landslides are apparent. The presence of active or intermittent natural influences that tend to cause slope failure. These include gravity, climatic conditions, fluvial processes, and the tendency of certain soils to shrink and swell under varying moisture conditions. These criteria are combined to yield the five-value scale used on the Relative Landslide Potential Map to indicate the comparative capacity of the slopes within the map area to resist failure by landsliding. The map, Landslide Potential with Geologic and Geomorphic Features, Freshwater Creek, Humboldt County, California is a digital representation of the map, Geological and Geomorphic Features Related to Landsliding, OFR 99-10, combined with the map of Relative Landslide Potential, OFR 99-10a. Purpose: The maps/data are useful in preparation of Timber Harvesting Plans, and for use by land managers for identifying areas of potentially unstable ground. The maps/data serve as a guide to potential problem areas where more site-specific review is required. Data Capture Procedures: As noted previously, geomorphic features were mapped on stereo pair photographs and transferred to 7.5 minute quadrangle mylar overlays. These overlays were scanned and converted to ArcInfo vector coverages. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  17. Title: Geologic map of the Juniper Hills quadrangle, Los Angeles County, California

    Contributors:

    Summary: by Thomas W. Dibblee, Jr.; edited by John A. Minch. Relief shown by contours and spot heights. "Prepared in cooperation with the California Department of Conservation, Division of Mines and Geology; and the U.S. Geological Survey." "Allan Barrows Honorary Map." "First printing, February 2002". Includes 2 col. cross sections, quadrangle location map, index to sources of geology, and index to adjacent 7.5 minute quadrangles. Includes "pertinent references".

    View full record

  18. Title: Geologic Units (Polygons), Freshwater Creek Watershed, California, 1999

    Contributors:

    Summary: This polygon shapefile represents geological units (such as fault contacts, lithographic contacts and the watershed boundary) within the Freshwater Creek watershed in Humboldt County, California at 1:24,000 scale. These data were derived from digital maps of landslide potential and geologic features in Humboldt County originally published in 1999 by the California Division of Mines and Geology (OFR 99-10 and OFR 99-10a). The data for the original mapping were compiled from multiple sources including published maps and reports, aerial photograph mapping, and reconnaissance geologic mapping. The maps/data are useful in preparation of Timber Harvesting Plans, and for use by land managers for identifying areas of potentially unstable ground. The maps/data serve as a guide to potential problem areas where more site-specific review is required. California Division of Mines and Geology and California Geological Survey. (2002). Geologic Units (Polygons), Freshwater Creek Watershed, California, 1999. California Dept. of Conservation and California Geological Survey. Available at http://purl.stanford.edu/dq241nm1562. The discussion below was excerpted from OFR 99-10 and 99-10a. The geology of the drainage is dominated by the Freshwater Fault. This fault is considered a normal fault with blocks on either side stepping down to the west in a regional context. Multiple strands of the fault appear to be present in the study area. The fault is considered inactive because no evidence of movement after late Quaternary time has been observed along it. The Freshwater Fault splits the watershed into two sections having different geologic conditions, topographic styles and potentials for landsliding (Plate 1). Much of the western half of the drainage has relatively steep topography underlain by gently dipping, interbedded mudstone, siltstone, sandstone and minor conglomerate of the Wildcat Group (early Pleistocene to late Miocene). These rocks are typically prone to shallow debris flows/slides and occasional translational/rotational rock slides. The Wildcat Group in this part of the drainage rests uncomformably atop interbedded sandstone and shale of the Yager Formation (early Tertiary). The Yager Formation dips steeply to the northwest (Plate 1). Only one translational/rotational rockslide was identified in this unit. Several lineaments were noted on the aerial photographs throughout this part of the drainage, but no faults are indicated. The geology of the eastern half of the drainage is complex and most of the larger translational/rotational landslides and earthflows are found there. The western third of this area is underlain by Wildcat Group rocks that rest unconformably atop dense sandstones and shales of the Yager Formation and Coastal Belt of the Franciscan Assemblage (PLATE 1). The contacts between Yager and Franciscan rocks probably represent multiple strands of the Freshwater Fault (Keith Knudsen, May 1999, personal communication). The remainder of the eastern half is dominated by a series of northeast-dipping thrust faults. These faults are considered inactive at this time because they are not indicated on the State of California Earthquake Fault Zone map (State of California, 1983). The thrust faults juxtapose irregular slabs of dense sandstone/shale and melange of the Coastal Belt of the Franciscan Assemblage. The erosional contrast between the two units is seen as discrete bands of "hard" and "soft" topography that cut through the drainage in a north-westerly direction (Plate 1). The characteristics and properties of the various rock units found in this area were taken into account during the assessment of relative landslide potential. The primary sources of geological data used in preparing the relative landslide potential map are compiled on Plate 1 of Open-File Report 99-10. The Relative Landslide Potential Map has been prepared to aid in resource management and general land-use planning. It is not intended, nor should it be used for, evaluation of specific sites. Site specific evaluations often require detailed engineering geologic studies and soil engineering investigations of the underlying soil and bedrock for proper planning of specific projects. This map is derivative, based on the following: 1) the occurrence and distribution landslides, other types of slope failure, and features indicating slope instability (Plate 1, Open-File Report 99-10); 2) the geology of the area, including bedrock types and lithologic properties relative to slope stability and distribution of various earth materials, as well as the structural framework, such as the folded and faulted strata found throught the region; and 3) the relative behavior of slopes within the area as interpreted from analysis of historic aerial photographs and recent field observations. Studies of the stability of specific sites commonly require development of quantitative data through laboratory testing of field samples. This level of testing was not done for this regional evaluation. In producing this map, it was assumed that actively sliding material has the lowest relative strength, and thus, the highest relative potential for landsliding of all the geological materials underlying the slopes. Recent alluvial deposits in the valley bottom were assumed to possess the least potential for landsliding due to their flat slope. The relative potential for landsliding between these extremes was evaluated subjectively based on aerial photograph interpretation, field observations and the following principal factors: The broad apparent stability characteristics of geological materials underlying the slopes and adjacent lower-lying areas, as expressed in their natural exposures and their observed responses to alteration by land-use activities. For example, slopes that exhibit abundant evidence of landsliding or downslope creep of the soil are considered oversteepened relative to the strength of the materials that underlie them. Steepness of slopes, whether or not landslides are apparent. The presence of active or intermittent natural influences that tend to cause slope failure. These include gravity, climatic conditions, fluvial processes, and the tendency of certain soils to shrink and swell under varying moisture conditions. These criteria are combined to yield the five-value scale used on the Relative Landslide Potential Map to indicate the comparative capacity of the slopes within the map area to resist failure by landsliding. The map, Landslide Potential with Geologic and Geomorphic Features, Freshwater Creek, Humboldt County, California is a digital representation of the map, Geological and Geomorphic Features Related to Landsliding, OFR 99-10, combined with the map of Relative Landslide Potential, OFR 99-10a. Purpose: The maps/data are useful in preparation of Timber Harvesting Plans, and for use by land managers for identifying areas of potentially unstable ground. The maps/data serve as a guide to potential problem areas where more site-specific review is required. Data Capture Procedures: As noted previously, geomorphic features were mapped on stereo pair photographs and transferred to 7.5 minute quadrangle mylar overlays. These overlays were scanned and converted to ArcInfo vector coverages. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  19. Title: Landslides, Freshwater Creek Watershed, California, 1999

    Contributors:

    Summary: This line shapefile represents landslide activity within the Freshwater Creek watershed in Humboldt County, California at 1:24,000 scale. These data were derived from digital maps of landslide potential and geologic features in Humboldt County originally published in 1999 by the California Division of Mines and Geology (OFR 99-10 and OFR 99-10a). The data for the original mapping were compiled from multiple sources including published maps and reports, aerial photograph mapping, and reconnaissance geologic mapping. The maps/data are useful in preparation of Timber Harvesting Plans, and for use by land managers for identifying areas of potentially unstable ground. The maps/data serve as a guide to potential problem areas where more site-specific review is required. California Division of Mines and Geology and California Geological Survey. (2002). Landslides, Freshwater Creek Watershed, California, 1999. California Dept. of Conservation and California Geological Survey. Available at http://purl.stanford.edu/kt474zt6227. The discussion below was excerpted from OFR 99-10 and 99-10a. The geology of the drainage is dominated by the Freshwater Fault. This fault is considered a normal fault with blocks on either side stepping down to the west in a regional context. Multiple strands of the fault appear to be present in the study area. The fault is considered inactive because no evidence of movement after late Quaternary time has been observed along it. The Freshwater Fault splits the watershed into two sections having different geologic conditions, topographic styles and potentials for landsliding (Plate 1). Much of the western half of the drainage has relatively steep topography underlain by gently dipping, interbedded mudstone, siltstone, sandstone and minor conglomerate of the Wildcat Group (early Pleistocene to late Miocene). These rocks are typically prone to shallow debris flows/slides and occasional translational/rotational rock slides. The Wildcat Group in this part of the drainage rests uncomformably atop interbedded sandstone and shale of the Yager Formation (early Tertiary). The Yager Formation dips steeply to the northwest (Plate 1). Only one translational/rotational rockslide was identified in this unit. Several lineaments were noted on the aerial photographs throughout this part of the drainage, but no faults are indicated. The geology of the eastern half of the drainage is complex and most of the larger translational/rotational landslides and earthflows are found there. The western third of this area is underlain by Wildcat Group rocks that rest unconformably atop dense sandstones and shales of the Yager Formation and Coastal Belt of the Franciscan Assemblage (PLATE 1). The contacts between Yager and Franciscan rocks probably represent multiple strands of the Freshwater Fault (Keith Knudsen, May 1999, personal communication). The remainder of the eastern half is dominated by a series of northeast-dipping thrust faults. These faults are considered inactive at this time because they are not indicated on the State of California Earthquake Fault Zone map (State of California, 1983). The thrust faults juxtapose irregular slabs of dense sandstone/shale and melange of the Coastal Belt of the Franciscan Assemblage. The erosional contrast between the two units is seen as discrete bands of "hard" and "soft" topography that cut through the drainage in a north-westerly direction (Plate 1). The characteristics and properties of the various rock units found in this area were taken into account during the assessment of relative landslide potential. The primary sources of geological data used in preparing the relative landslide potential map are compiled on Plate 1 of Open-File Report 99-10. The Relative Landslide Potential Map has been prepared to aid in resource management and general land-use planning. It is not intended, nor should it be used for, evaluation of specific sites. Site specific evaluations often require detailed engineering geologic studies and soil engineering investigations of the underlying soil and bedrock for proper planning of specific projects. This map is derivative, based on the following: 1) the occurrence and distribution landslides, other types of slope failure, and features indicating slope instability (Plate 1, Open-File Report 99-10); 2) the geology of the area, including bedrock types and lithologic properties relative to slope stability and distribution of various earth materials, as well as the structural framework, such as the folded and faulted strata found throught the region; and 3) the relative behavior of slopes within the area as interpreted from analysis of historic aerial photographs and recent field observations. Studies of the stability of specific sites commonly require development of quantitative data through laboratory testing of field samples. This level of testing was not done for this regional evaluation. In producing this map, it was assumed that actively sliding material has the lowest relative strength, and thus, the highest relative potential for landsliding of all the geological materials underlying the slopes. Recent alluvial deposits in the valley bottom were assumed to possess the least potential for landsliding due to their flat slope. The relative potential for landsliding between these extremes was evaluated subjectively based on aerial photograph interpretation, field observations and the following principal factors: The broad apparent stability characteristics of geological materials underlying the slopes and adjacent lower-lying areas, as expressed in their natural exposures and their observed responses to alteration by land-use activities. For example, slopes that exhibit abundant evidence of landsliding or downslope creep of the soil are considered oversteepened relative to the strength of the materials that underlie them. Steepness of slopes, whether or not landslides are apparent. The presence of active or intermittent natural influences that tend to cause slope failure. These include gravity, climatic conditions, fluvial processes, and the tendency of certain soils to shrink and swell under varying moisture conditions. These criteria are combined to yield the five-value scale used on the Relative Landslide Potential Map to indicate the comparative capacity of the slopes within the map area to resist failure by landsliding. The map, Landslide Potential with Geologic and Geomorphic Features, Freshwater Creek, Humboldt County, California is a digital representation of the map, Geological and Geomorphic Features Related to Landsliding, OFR 99-10, combined with the map of Relative Landslide Potential, OFR 99-10a. Purpose: The maps/data are useful in preparation of Timber Harvesting Plans, and for use by land managers for identifying areas of potentially unstable ground. The maps/data serve as a guide to potential problem areas where more site-specific review is required. Data Capture Procedures: As noted previously, geomorphic features were mapped on stereo pair photographs and transferred to 7.5 minute quadrangle mylar overlays. These overlays were scanned and converted to ArcInfo vector coverages. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  20. Title: Maps and GIS data for the Watersheds mapping series

    Contributors:

    Summary: Contains PDF copies of the originals, as well as digital presentations of, the documents and maps produced from the Freshwater Watershed Mapping Project. These documents, Geologic and geomorphic features related to landsliding, Freshwater Creek, Humboldt County, California; and, Relative landslide potential map, Freshwater Creek, Humboldt County, California, were completed by James N. Falls in 1999 and issued as Open-file report 99-10 and 99-10a by the California Division of Mines and Geology. by James N. Falls ; compiled by Lisa Ohara and Dave Dixon. Title from CD cover. Includes: Factors affecting landslides in forested terrain (California. Division of Mines and Geology. Note 50). System requirements: Intel Pentium processor or Macintosh Power PC or later with CD-ROM drive; Microsoft Windows 95 OSR2.0, Windows 98SE, Windows Millenium, Windows NT 4.0 with service pack 5, or Windows 2000, Macintosh OS8 or later; 64 MB RAM for any Windows platform; 16 MB RAM (32 MB recommended) for Macintosh; 24 MB available hard disk space; Acrobat Reader 5.0 (included on disc) to view the reference images; Arcview or Arcinfo to view GIS data. Graphics files (.gra, .rtl and .pdf formats) for five maps; Arcinfo export files; Arcview shape files; text files (.rtf, .txt and .pdf)

    View full record

Need help?

Ask GIS