Description: <DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>Landslide Records describe the slope movement feature through the attributed Fields and is placed at the approximate Head Scarp or Initiation Zone of a landslide. </SPAN><SPAN>Landslide Record placement is determined from field investigations, features visible in various vintages (1940–most current) of aerial photography and orthophotography, and a variety of derivatives from Light Detecting And Ranging (LiDAR) Digital Elevation Models (DEM). When possible Landslide Records have associated Landslide Footprints (polygon feature class). Fields of this layer include descriptions of slope movement type, location, dimensions, movement dates,</SPAN><SPAN> methods of mapping, detailed field observations about the morphology of a landslide, the timing and rate of movement, Head Scarp material and bedrock structure, and whether the landslide has been field verified.</SPAN></P></DIV></DIV></DIV>
Copyright Text: North Carolina Geological Survey (NCGS)
Mvmnt_Date
(
type: esriFieldTypeString, alias: Movement Date (yyyy/mm/dd), length: 30
)
Other_Mvmt
(
type: esriFieldTypeString, alias: Other Movement Dates, length: 100
)
Field_Ver
(
type: esriFieldTypeString, alias: Field Verified , length: 35
, Coded Values:
[Field verified by NCGS: Field verified by NCGS]
, [Field verified by Data Source 1: Field verified by Data Source 1]
, [Not field verified: Not field verified]
)
Description: <DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>Landslide Features show the approximate areal extents of relatively recent, individual slope movements where their initiation (source) areas are known. Landslide Features are mapped from field investigations, features visible in various vintages (1940–most current) of aerial photography and orthophotography, and a variety of derivatives from Light Detecting And Ranging (LiDAR) digital elevation models (DEM). </SPAN><SPAN>Head Scarp, lateral scarps, and the toe of a feature must be identifiable in remote and/or field mapping before a feature is designated as a Landslide Feature.</SPAN><SPAN><SPAN> </SPAN></SPAN><SPAN>All Landslide Features are paired with at least one Landslide Location (point) at the Head Scarp or Initiation Zone of the feature, for two reasons: 1) the Landslide Location contains details about the release surface and the type of material that has moved; 2) we can show a county or region-wide spatial distribution of landslides as Landslide Locations (point) on a smaller-scale map by setting the size of the points so they are legible on a large area map in such a way that would not be possible with Landslide Feature polygons.</SPAN></P></DIV></DIV></DIV>
Copyright Text: North Carolina Geological Survey (NCGS)
Description: <DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>These colluvial and alluvial deposits represent the areal extents of significant volumes of earth, debris, and rock fragments that could have accumulated in part because of past debris flows and debris slides and, to a lesser extent, rock falls and rockslides. These colluvial and alluvial deposits indicate areas that can be affected by landslides and can be unstable in some circumstances. The bulk of the deposits are likely prehistoric in age, but their ages have yet to be verified by modern age-dating techniques. Colluvial deposits consist of heterogeneous mixtures of clay, silt, and sand particles with gravel- to boulder-sized rock clasts in various stages of weathering and decomposition. Areas mapped as deposits met two or more of the following criteria: 1) exhibited an elongate, lobate or fan shape, or other landform characteristic of a slope movement deposit, visible at a scale of <1:7,500 using Light Detecting And Ranging (LiDAR) digital elevation model (DEM) derivatives; 2) had an adequate upslope source area where past slope movements could have initiated; 3) were verified in the field to contain gravel- to boulder-sized clasts or other textures and depositional structures that characterize deposits produced by slope movements (i.e. matrix supported or imbricated clasts, or scour and fill structures); and/or contained boulder deposits visible in some recent orthophotography. Many narrow stream valleys likely contain colluvial deposits that are not feasible to map at this scale.</SPAN></P></DIV></DIV></DIV>
Copyright Text: North Carolina Geological Survey (NCGS)
Field_Ver
(
type: esriFieldTypeString, alias: Field Verified, length: 35
, Coded Values:
[Field verified by NCGS: Field verified by NCGS]
, [Field verified by Data Source 1: Field verified by Data Source 1]
, [Not field verified: Not field verified]
)