Mexico, an area undergoing secular change in gravity

Abstract

There are few places in the world where there are adequate data to demonstrate past or present secular changes in gravity. There are places where there have been marked local changes in gravity of the order of 1 mgal or more in association with crustal displacement related to earthquakes or surface subsidence due to underground mining or oil field pumping, but little evidence to support regional continuous change in gravity. Boulanger (personal communication) feels that repeat gravity measurements with multiple gravimeters at key sites between Moscow and Vladivostok indicate one such area in the eastern USSR, but in the writers' experience in conducting gravity measurements since 1939, the only other location where a secular change in gravity appears to be well substantiated is the southern end of the plateau of Mexico.