GIS Lookup: Detailed Data Layer Listing

Data Layer GraphicTitle: "Landslides" (2005)
Description: The North Carolina slope movement-slope movement deposit database (NCSM-SMD database) covers all of North Carolina. The NCSM-SMD databases includes slopemovement and deposit type, location, dimensions, dates, geologic (rock and soil), geomorphic and other site data for individual slope movements, and slope movement deposits. While the majority of the slope movement (landslide) events have occured mountainous western North Carolina, other parts of the state are not immune from such events. Initial data collection by the North Carolina Geological Survey (NCGS) began in 1990, but the impetus to assemble these data arose from a collaborative effort, beginning in 2004, between the North Carolina Division of Emergency Management, NCDEM, and the NCGS, to establish a statewide inventory of geological hazards. The geological hazard inventory currently includes the locations of and information on slope movements and slope movement deposits, earthquakes, historic mines, sinkholes, and a number of additional geological hazards. Further impetus to develop the NCSM-SMD database resulted from at least 90 slope meovements triggered by the inland tracking of hurricanes during September 2004. These slope movements resulted in a total of five deaths and 27 destroyed or heavily damaged homes. Reported landslides for which there are geographic coordinates are in the accomapanying data table and are present in the ESRI shape file. As of 15 February 2005 there are a total 497 slope movement-slope movement deposit records in the database; of these 446 have geographic coordinates. Those deposits without coordinates are not plotted but listed in the metadata abstract in an abbeviated format. The following is a glossary of terms used to describe the slope movements and slope movement deposits in this database. The project data is stored in a MS Access database in the NCGS's Swannanoa office. NCGS Slope Movement ? Deposit Database Fields Deliverable Metadata Field Name ID: Sequential database number beginning with 1. Project is a name for a project, example Blue Ridge Parkway or Geohazards Entry Type is an entry specifying either Process: A known specific slope movement where a movement mechanism is known, or can be readily inferred Deposit: Slope movement deposit Slope Movement Name is the informal geographic name of slope movement designated by NCGS, example Charley Branch #4 Slope Movement Type is the classification of slope movement, example process 1, debris flow, debris slide, debris slide-flow, rockslide, rock fall, weathered-rock slide, embankment failure, other-specify Slope Movement Deposit is the classification of slope movement deposit, these include debris1 undifferentiated, debris1 fan, composite debris fan, colluvial-alluvial fan, earth1 undiff, colluvium undiff, colluvium toe slope, colluvial hollow, block field, block stream, talus, or other that is specified Date Data Collected is that the date the data was collected in month, day, year data format Date of Movement in date of movement in month, day, year data format County is the county name Quad is the 7.5-minute United States Geological Survey quadrangle name Coordinates2 Latitude3 is the latitude in decimal degrees to 5 decimal places if possible. Longitude3 is the longitude in decimal degrees to 5 decimal places if possible. State Plane Meters4 is the northing and Easting to 5 decimal places where possible. Elevation Head/Apex is the elevation in feet from USGS 7.5-minute topographic map of head of slope movement or apex of slope movement deposit. Highway-Road is the road name and/or number Data Source is the source of data, example NCGS, USFS, EM-Swain County. Location Confidence: Confidence in accuracy of location NCGS field verified: 7.5-minute US Geological Survey quadrangle with a positional accuracy accurate within a 400-foot radius in the worst case NCCS field verified: using another source with accuracy unknown NCGS field verified: field verified GPS with an accuracy to be accurate within a 40-foot radius NCGS field verified aerial photograph is accurate within a 200-foot radius in the worst case NCGS not field Verified: accuracy is unknown, location not field verified by other means. Accuracy of height ismade from dimensions for slope movements and deposits made by visual estimates, or scaled from maps and or aerial photographs Slope Configuration: Configuration of slope on which movement occurred types, road cut, road embankment, road unspecified or unmodified cut slope ? not road related embankment-not road related other-specify Displaced Mass Length is the estimated length of displaced mass in feet. Displaced Mass Width is the estimated width of displaced mass in feet. Displaced Mass Thickness is the estimated thickness of displaced mass in feet. Track Length is th length of track from the head to the toe in feet, mainly for debris flows. Damage-Impacts is the text narrative of any damage or impacts of slope movement, example road damage, stream sedimentation, house damage. Movement History is the text narrative of movement history, example, dates, rates of movement if continued beyond initial date of movement; also includes information on any stabilization actions. Remarks is the text narrative of any additional information pertinent to entry, example reference for a source, general comments, repairs. NCGS Investigators is the initial or initials of NCGS investigators. Notes Vertical lists within fields indicate specified categories for database entries. Classified in general accordance with Cruden, D.M. and Varnes, D.J., 1996, Landslide types and processes,in Landslides: Investigation and Mitigation, Turner, A.K. and Schuster, R.L., eds. Transportation Research Board Special Report No. 247, National Research Council, National Academy Press, Washington, D.C., p. 36-75. Varnes, D.J., 1978, Slope movement types and processes, in Landslide Analysis and Control, edited by R.L. Schuster and R.J. Krizak, Transportation Research Board Special Report No. 176, National Academy of Sciences, Washington, D.C., p. 11-33. Coordinates given in latitude, longitude; and, NAD83 state plane meters in the spreadsheet version of the database for NCEM. Latitude and longitude location at initiation point, usually head scarp, for slope movements; or at apex of slope movement deposits. State plane coordinate location at initiation point, usually head scarp, for slope movements; or at apex of slope movement deposits. Glossary of North Carolina Slope Movement follows alluvium is clay, silt, sand, gravel or similar unconsolidated detrital material deposited during relatively recent geologic time by a stream or other body of running water. Alluvium usually contains rounded particles and usually collects in the channels and floodplains of creeks, streams, rivers, and lakes (adj alluvial). apex is the uppermost and usually narrowest part of a debris fan deposit nearest the source area of the fan. block stream is an accumulation of boulders or angular blocks of rock, with little or no fine sediment in the upper part over bedrock or other hillslope deposit. Block streams usually occur at heads of ravines, as narrow bodies more extensive downslope than along slope. block field is a thin accumulation of boulders or angular blocks of rock, with little or no fine sediment in the upper part over bedrock or other hillslope deposit without a cliff or a ledge above as an apparent source. Block fields usually occur on high mountain slopes where they are most extensive along slopes parallel to contour. boulder is a detached rock mass larger than a cobble, having a diameter greater than 256 mm. clay is a rock or mineral fragment or a detrital particle of any composition smaller than a very fine silt grain, having a diameter less than 0.004 mm. cobble is a rock fragment larger than a pebble and smaller than a boulder, having a diameter in the range of 64 mm to 256 mm. colluvium is any loose, heterogeneous, and unconsolidated mass of soil and rock particles deposited by rainwash, sheetwash, or slow, continuous downslope creep. Colluvium usually contains angular to subrounded rock particles and usually collects at the base of gentle slopes or hillsides. colluvial-alluvial fan is a fan deposit that contains both alluvium and colluvium. colluvial-hollow is a hillslope landform represented by a depression or concave portion of the slope containing colluvium. colluvium toe slope is a database category of colluvial deposit that has accumulated along the lower part, or toe, of a hillslope, but without a distinctive fan shape. composite debris fan is a debris fan composed of more than one generation of either colluvium or alluvium that reflects more than one period of fan deposition. creep is the slow, more or less continuous downslope movement of mineral, rock, and soil particles by gravity. cut slope is a slope exposed by excavating earth materials. debris is regolith that contains a significant proportion of coarse material in which 20% to 80% of the particles are greater than sand sized in the range of 0.08 in or 2 mm. Debris is a general term used to classify the coarser-grained material in the source area of a slope movement, example debris flow or debris slide. debris fan is a fan-shaped accumulation of debris typically along the lower gentle slope of a hillside. debris flow is a type of slope movement in which the water content in the displaced mass is sufficient for the material to liquefy and resemble a viscous fluid. Flows involve the movement of unconsolidated earth materials, such as earth and debris, in a semi-fluid state. debris slide is slope movements initiated by slippage along a well-defined failure surface that is usually planar or curvi-planar. Slides are divided into two classes, rotational and translational. Slides usually consist of displaced and deformed blocks of material debris slide-flow is a slope movement with characteristics of a debris slide and a debris flow. A slope movement may begin as a debris slide, and then mobilize into a debris flow if sufficient water is available deposit is earth material of any type that has accumulated by some natural process or agent 'vb deposited' or, an accumulation of ore or other valuable earth material dip slope is a slope of the land surface, roughly determined by and conforming with, the direction and angle of the dip of the underlying rock earth is regolith in which about 80% or more of the particles are smaller than 2 mm. Earth is a general term used to classify the finer-grained type of material in the source area of a slope movement, examples earth flow or earth slide embankment is an-made deposits of natural earth materials, example rock, soil, or gravel, used to extend a sideslope or a land surface, example for a roadway or building site, build up low-lying land, hold back water, example a dam, or fill in an enclosed space, example mine workings. Synonymous with man-made fill, but distinguished from naturally occurring, sedimentary fill. foot slope is the lower gentle slope of a hillside below a steep rock face or escarpment including lower slopes of diminishing steepness. formation is a body of rock identified by its unique lithologic characteristics and stratigraphic position. gravel is an unconsolidated, natural accumulation of rounded rock fragments resulting from erosion and consisting predominantly of particles larger than sand but smaller than cobbles greater than >2mm and smaller than <64mm. ground water is water below the surface of the Earth. Also spelled: groundwater, ground-water. head is the upper parts of the slope movement material in contact between the displaced material and the main scarp. joint is a fracture or parting in a rock, without displacement. landslide is a wide variety of mass movement landforms and processes involving the downslope transport, under gravitational influence, of soil and rock material en masse. The term ?slope movement? is used here instead to include movement by flowing, falling and sliding. lithology is the description of rocks, especially in hand specimen and in outcrop, on the basis of such characteristics as color, mineral composition, and grain size (adj lithologic). mineral is a naturally occurring, inorganic substance having an orderly internal crystalline structure, characteristic chemical composition, and physical properties. oblique slope is a relatively steeper face of a hillslope, facing in a direction at an angle to the dip of the rock layers. An oblique slope faces a direction that lies between a dip slope and a scarp slope. pebble is a general term for a small, rounded, water- worn stone; specifically, a rock fragment larger than a granule and smaller than a cobble, having a diameter in the range of 4 mm to 64 mm. pore water is subsurface water in the voids of rock, sediment, or soil. quadrangle is a rectangular area bounded by parallels of latitude and meridians of longitude. In this database ?quadrangle? means a 7.5-minute U.S. Geological Survey topographic quadrangle map, 1:24,000 scale. regolith is a general term for the layer or mantle of fragmental and unconsolidated rock material that nearly everywhere forms the surface of land and overlies or covers bedrock. It includes alluvium, colluvium, residuum, debris, earth, and soil. residuum is a unconsolidated or partly weathered parent material, soil, that developed in place by the physical and chemical weathering from the consolidated rock on which it lies. rock is an aggregate of one or more minerals, undifferentiated mineral matter, or solid organic material. rock fall is a type of slope movement in which a single mass of rock of any size is detached from a steep slope or cliff along a surface on which little or no shear displacement occurs. The detached material descends mostly through the air by free fall, bounding, or rolling. rotational movementis a term used to describe the type of movement in a slide in which the displaced material has moved along a curved, concave upward, failure surface sand is a rock or mineral fragment or a detrital particle of any composition smaller than a granule and larger than a coarse silt grain, having a diameter between 0.004 mm and 2 mm. saprolite is a soft, earthlike, completely decomposed,or weathered, in-place rock material typically formed in humid environments. Saprolite is characterized by the preservation of structures that were present in the unweathered rock. scar is a cliff, precipice, or other steep slope, that corresponds to the zone of depletion, or the area from which a slope movement originated scarp is a cliff like face or slope that breaks the general continuity of the land surface around or in a slope movement, and coincides with a rupture of the ground surface with differential displacement. The main scarp is above the head of the slope movement, and usually forms the upper periphery of the displaced mass; a minor scarp is a rupture of the ground surface with differential displacement in the body of the displaced mass. scarp slope is a relatively steeper face of a hillslope, facing in a direction opposite the dip of the rock strata or layers. sediment is loose, unconsolidated, fragmental material that originates from weathering of rocks and is transported or deposited by air, water, or ice. shear strength is the internal resistance of a body to shear stress. silt is a rock or mineral fragment or a detrital particle of any composition smaller than a very fine sand grain and larger than coarse clay, having a diameter between 0.004 mm and 0.06 mm. slope movement is the gradual or rapid downslope movement by falling, flowing, or sliding or combinations of these of regolith or rock by gravity. Used here in place of the term ?landslide.? strike is the direction or trend taken by a structural surface,example a bedding, foliation, or fault plane, as it intersects the horizontal. structure is a feature in the rock that results from rock deformation. surficial deposit is an unconsolidated and residual, alluvial, or glacial deposits lying on bedrock or occurring on the Earth?s surface. talus is a rock fragments of any size or shape, usually coarse and angular, derived from and lying at the base of a cliff or very steep rocky slope. tension crack is a crack or rupture in the ground surface caused by extension or tensile stress but not showing differential vertical displacement. With continued displacement a scarp can form from a tension crack. toe is the lowest part of a slope, slope movement or slope movement deposit. topographic map is a map showing the topographic features of the land surface. track is the path of a channelized debris flow between the scar or source area upslope, and the toe or depositional area downslope. The track usually coincides with a pre-existing stream channel or drainage way. translational movement is a term used to describe the type of movement in a slide in which the displaced material has moved along a generally planar failure surface. weathered-rock slide is a term used to describe a rockslide where the displaced rock is partly- to completely decomposed from physical and chemical weathering processes. weathering is the physical disintegration and chemical decomposition of rock at the Earth?s surface. Boone100klines shape file: Outline of area containing major slope movements triggered by back-to-back hurricanes in July and August 1940. September 1940 vintage aerial photographs for the Deep Gap-Boone area were viewed using a stereoscope. Aerial photographs containing significant numbers of slope movements, greater than approximately 10 per photo, were selected from the group of photos. Using the selected aerial photographs, slope movements were mapped onto transparent overlays at an approximate scale of 1:18,000. The selected aerial photographs were located on the Boone 1:100,000 scale topographic map, and a dot was placed on the map indicating the approximate center of the photo. A boundary was drawn on the 100k topographic map based on the location of the selected aerial photographs as well as the topography. The boundary was ?heads-up? digitized by NCGS staff. Boundary represents area with high concentration of debris flows primarily attributed to the August 10-17, 1940 storm event. Accurac y of boundary placement is estimated to be within 1000 feet. No features have been field checked. Aerial photography interpretation occurred between May 2004 and July 2004. These data provide an inventory or landslides in North Carolina as of 15 February 2005 in support of a geohazards inventory of North Carolina funded through FEMA and the North Carolina Division of Emergency Managment
Keywords and Themes: Geologic Hazards, Landslides, Mountain Flooding
Filename Prefix: landslides
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Mapped Drive Folder: /cgia83/ncom200703/
Total size of data files: 0.16593 MB
Data Type: Shapefile
Feature Type: Point
Coordinate System: NAD_1983_StatePlane_North_Carolina_FIPS_3200
Datum: North American Datum of 1983Map Units: Meters

Spatial Extent: North Carolina

Created by: NC DENR - Div. of Land Resources; NC Geological Survey
Released by: NC Center for Geographic Information & Analysis
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Collection Name: NC OneMap - 3/12/2007
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Acquired Date: Downloaded Mar 12, 2007
Distribution Restrictions: Public Domain

Note: Public download and possible updated data are available from NC OneMap

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Record ID: 3046_NCOM0703