Applications of a field absolute gravimeter for monitoring temporal gravity changes

Abstract

In order to detect the gravity changes associated with various phenomena, for instance, groundwater changes and land subsidence, we have conducted absolute gravity measurements using a field absolute gravimeter Micro-G LaCoste Inc. A10-017. Although those phenomena can be detected by conventional methods such as water gauge and spirited leveling, only gravity measurements can provide useful information about the mass changes, which is the key for the interpretation of the phenomena. So far, we have conducted repeated gravity measurements using A10-017 at several test fields in Japan and Indonesia for monitoring the geothermal fluid, groundwater variations, land subsidence and volcanic activities. We report the outline of the surveys and some results mainly from the viewpoints of absolute gravimetry, and discuss the applicability of A10 as a field absolute gravimeter for monitoring temporal gravity changes.