Inertial effects due to eruption-induced atmospheric disturbances identified by superconducting gravimeter observations at Matsushiro, Japan

Abstract

The violent eruption of Hunga Tonga-Hunga Ha’apai volcano on January 15, 2022 induced strong atmospheric disturbances, which traveled around the world as atmospheric Lamb waves. When this wave passed through the superconducting gravimeter station at Matsushiro, Japan, a large signal of gravity changes was recorded. Also, barometers installed around Matsushiro recorded wave trains of pressure changes. Analysis of the barometer data revealed that the atmospheric disturbances traveled as plane waves. Applying the theory of atmospheric loading for traveling plane waves, the observed gravity changes were well reproduced by a sum of three components of atmospheric loading, namely, Newtonian, free-air and inertial effects. In particular, the inertial effect of atmospheric loading, which is rarely observed, was clearly identified in the gravity data. From the theoretical modeling, an estimate of rigidity in the shallow region of the Earth was also obtained. Graphic Abstract: [Figure not available: see fulltext.].