This may be for subscribers to Science News only, but it has a terrific photo that vividly illustrates ground subsidence.
Withdrawal of groundwater in California's San Joaquin valley has caused the ground to subside by more than 9 m. Signs in this 1977 photo, taken near Mendota, show where the ground surface was in 1925 and 1955.
U.S. Geological Survey
Thanks for posting.