Abstract
Gravity change measurements may be one of the easier ways of detecting tectonic changes induced by an earthquake. In this paper, the gravity data measured during and after the Matsushiro Earthquake Swarm are compiled, and the relationship between gravity and elevation changes is discussed. It is concluded that the elevation of the epicentral area lifts up without any change in subsurface apparent density but sinks with a density increase. We have recently observed density decrease there again, but a possible cause of the decrease remains still unknown.
