Tags
Each landslide should be classified into one the following types of movement : 1) slides 2) flows, 3) spreads, 4) topples, 5) falls, 6) complex.
DOGAMI SP 42
Landslides should be differentiated by the kinds of material involved and the mode of movement. A classification system based on these parameters was developed by Varnes (1978) and can be found in DOGAMI SP-42.
DOGAMI SP 42
Movement code combining type of movement and type of material. For example, debris flow would be DFL.
DOGAMI SP 42
Confidence of identification: high, moderate, low
DOGAMI SP 42
Estimated age: historical landslide age less than 150 years, prehistorical greater than 150 years
DOGAMI SP 42
Date of landslide failure
DOGAMI SP 42
Landslide name
DOGAMI SP 42
Geologic unit that the landslide occurred in
DOGAMI SP 42
Adjacent slope angle in degrees
DOGAMI SP 42
Change in elevation from bottom to top of head scarp in feet
DOGAMI SP 42
Change in elevation from top to toe of fan in feet
DOGAMI SP 42
Estimate and/or calculated slope normal thickness of failure depth in feet
DOGAMI SP 42
The landslide is shallow seated (less than 15 feet) or deep seated (greater than 15 feet)
DOGAMI SP 42
Horizontal distance in feet from head scarp to internal scarp no. 1
DOGAMI SP 42
Horizontal distance in feet from internal scarp no. 1 to internal scarp no. 2
DOGAMI SP 42
Horizontal distance in feet from internal scarp no. 2 to internal scarp no. 3
DOGAMI SP 42
Horizontal distance in feet from internal scarp no. 3 to internal scarp no. 4
DOGAMI SP 42
Calculated average horizontal distance in feet between scarps
DOGAMI SP 42
Direction of movement of the landslide in Azimuth degrees
DOGAMI SP 42
Size of landslide deposit in square feet
DOGAMI SP 42
Volume of landslide deposit in cubic feet
DOGAMI SP 42
Unique code assigned by data steward to each landslide polygon in database
DOGAMI SP 42
DOGAMI SP 42
Landslide deposit polygons
DOGAMI Special Paper 42
This feature class consists of polygons delineating landslide deposits (including debris flow fans and talus extent).
This data set is an inventory of mapped landslide deposits in the Douglas County study area. This inventory is not regulatory, and revisions can happen when new information regarding landslides is found or when future (new) landslides occur. The landslide inventory is intended to provide users with basic information regarding landslides. The geologic, terrain, and climatic conditions that led to landslides in the past may provide clues to the locations and conditions of future landslides, and it is intended that this data will provide useful information to develop regional landslide susceptibility maps, to guide site-specific investigations for future developments, and to assist in regional planning and mitigation of existing landslides.
Publication
None
REPORT DATA: This product is for informational purposes and may not have been prepared for or be suitable for legal, engineering, or surveying purposes. Users of this information should review or consult the primary data and information sources to ascertain the usability of the information. This publication cannot substitute for site-specific investigations by qualified practitioners. Site-specific data may give results that differ from the results shown in the publication. See the accompanying text report for more details on the limitations of the methods and data used to prepare this publication.
When contacting DOGAMI about this data set, please reference the data set title or other identifying information in your correspondence. DOGAMI publications can be downloaded from http://www.oregongeology.org
The project described in this publication was supported in part by Federal Emergency Management Agency grant HMGP 4258 8-F.
Relevant attributes from SP-42 were filled in when applicable and visually checked for accuracy.
Landslide polygons were mapped and attributed for this landslide inventory specific study using Special Paper 42 methodology.
The study area encompasses the coastal Douglas County. This data set includes all landslide deposit polygons within the study area for Douglas County; with the exceptions of landslides that are smaller than 100 square meters (1,075 square feet) which may not be identified due to the resolution of the lidar data and air photos used in this project area.
The line work for Landslide Inventory was captured by heads up digitizing at a 1:4,000 scale. Base map used for digitization was DOGAMIs bare earth lidar. Lidar data quality requires that the average departure from planarity within any 10 meters area shall be no greater than 5 cm. However, the accuracy will still vary with the skill and care of the individual mapper.
Maximum error calculated from the 1:4000 scale horizontal positional accuracy error.
Lidar-derived bare earth elevation model vertical accuracy is typically less than 1 foot.
Maximum error from lidar.
This data was prepared using a wide variety of interpretation methods, including aerial photos, field work, map digitizing, and methods following the Protocol for Inventory Mapping of Landslide Deposits from Light Detection and Ranging (Lidar) Imagery developed by Burns and Madin (DOGAMI Special Paper 42, 2009). In the Special Paper 42, the three primary tasks include compilation of previously mapped landslides, lidar-based morphologic mapping of landslide features, and review of aerial photographs. Landslides identified by these methods are digitally compiled into this database at varying scales. While the protocol recommends data use at a map scale of 1:8,000, and the geodatabase contains data at 1:8,000 or better, for representation purposes the data have been visualized on the map plate at 1:32,000. Each landslide is also attributed with classifications for activity, depth of failure, movement type, and confidence of interpretation.
When contacting DOGAMI about this data set, please reference the data set title or other identifying information in your correspondence. DOGAMI publications can be downloaded from http://www.oregongeology.org
Landslide deposit polygons
DOGAMI Special Paper 42
When contacting DOGAMI about this data set, please reference the data set title or other identifying information in your correspondence. DOGAMI publications can be downloaded from http://www.oregongeology.org
Although these data have been processed successfully on a computer system at the Oregon Department of Geology and Mineral Industries, no warranty expressed or implied is made by DOGAMI regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty.
When contacting DOGAMI about this data set, please reference the data set title or other identifying information in your correspondence. DOGAMI publications can be downloaded from http://www.oregongeology.org