San Joaquin Valley Land Subsidence Monitoring Network (1926-1970)

History of the San Joaquin Valley Land Subsidence Monitoring Network

A subsidence monitoring network in the San Joaquin Valley was implemented in the 1960s to help quantify the extent and magnitude of the subsidence that was first discovered in the 1950s. In the 1960s and 1970s, the USGS managed 31 extensometers operating at 21 sites and extensive spirit-leveling networks.