Survey monument positions for the Cleveland Corral landslide near U.S. Highway 50, El Dorado County, California (ver. 2.0, December 2024)

Data in this document record the ground-surface positions from 1996 to 2018 of monuments located on different kinematic elements of the Cleveland Corral landslide, or on nearby more stable ground. Data were collected about once a year in campaign mode, at times when the landslide was dormant and not moving (typically late spring or fall). Survey timing was selected to identify wet-season movement of the slide, which typically occurs during the winter and spring. Between 1996 and 2000, positional information was collected by surveying pins (with rod and prism) from a total station instrument located across the valley from the landslide. Between June 2000 and March 2004, no surveys were performed. Starting in 2004, positional information for monuments was determined using static differential Global Positioning System (GPS) surveying techniques with a nearby reference site located on stable ground. Details of the GPS surveying and processing techniques are further described in the Data_Quality_Information section of the FGDC Metadata. One file is provided for each of the two periods of measurement. Initial monuments were pins (large nails) and rebar for aerial photo targets located on and off the active slide. These were replaced or supplemented by rebar in 1999 and 2000. When GPS surveying began, new rebar with aluminum-cap monuments were driven into the ground. The number of monuments evolved over the years as some were destroyed or buried by landslide activity and others added. This data release includes four files: 1) geographic positions of survey pins/rebar, 1996 - 2000, 2) geographic positions of GPS monuments starting in 2004, 3) image showing the locations of the pins and monuments, and 4) the 2004 OPUS solution used to obtain the GPS base-station position.
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