Abstract

Meteotsunamis triggered by atmospheric disturbances of Lamb waves due to the 2022 Hunga Tonga volcanic eruption were observed in coastal areas surrounding the Pacific Ocean. However, the spatio-temporal evolution of the meteotsunami wavefield remain elusive due to the lack of geophysical observations in the ocean. Here, we show a detailed distribution of the propagation velocities and directions of the meteotsunamis in the bathymetric slope area between the Japan Trench and nearshore, using 150 absolute pressure gauges deployed at water depths of 100--8000 m. We also illuminate the generation of free waves, i.e., tsunamis, which occur when the meteotsunamis propagate at the slope area. Large amplitudes of the meteotsunamis are produced in the southern part of the slope area, which is caused by the relationship between the incoming direction and the gradient of the bathymetry. Our findings establish a link between seafloor pressure measurements and the Lamb wave-excited wavefields.