This report consists chiefly of 41 tables that both describe and fully document the reconstructions of a series of alternately developed heights based on levelings leading into two representative bench marks in the southwestern United States. One of these marks, 3219, Vincent, California (fig. 1), lies within the area of the Pacific-North American plate boundary; the other, 22Q, Bill Williams River, Arizona (fig. 1), falls within what is believed to be a singularly stable section of southwestern Arizona. Because the levelings that produced these heights were characterized by especially disparate routes with respect to both terrain and climate, the resulting heights provide a test for the existence and magnitude of path-dependent error in geodetic leveling. These two marks were chosen both because of their relative stability with respect to adjacent marks and because their tectonic stability (or instability) can be inferred from the geologic record. Specifically, we can reasonably speculate that 3219 may have sustained measurably significant tectonic displacements during the 20th century, whereas 22Q probably has remained virtually invariant with respect to any fixed datum during the same period.
Bench mark 3219 is a standard Geological Survey iron post stamped "3219" near the Southern Pacific Railroad station at Vincent (U.S. Geological Survey, 1898, p. 392); 22Q is a brass cap stamped "22Q (MWD)" set in a concrete post located in a gully immediately north of the Bill Williams River, Arizona (USC&GS Quad. 34114). 3219 was established by the Geological Survey no later than 1897 (Gannett and Baldwin, 1907, p. 365); 22Q was established by the Metropolitan Water District of southern California in advance of the 1931 control surveys along the projected route of the Colorado River Aqueduct.
|Publication Subtype||USGS Numbered Series|
|Title||Sequentially and alternatively developed heights for two representative bench marks: near Palmdale, California and along the Bill Williams River, Arizona|
|Series title||Open-File Report|
|Publisher||U.S. Geological Survey|
|Description||ii, 50 p.|
|Google Analytic Metrics||Metrics page|