Meteotsunami Observed by the Deep-Ocean Seafloor Pressure Gauge Network Off Northeastern Japan

Abstract

This study reports an ocean-bottom pressure gauge (OBP) network, S-net, which captured meteotsunamis with amplitudes as small as a few cm, and investigates its validity and limitation for meteotsunami research studies through data analyses and numerical simulations. On July 1, 2020, S-net recorded tsunami-like signals, although no earthquake was reported. These waves, propagating northward with a velocity of ∼110 m/s, were explained by an atmospheric low pressure with a maximum amplitude of −0.5 ± 0.1 hPa moving northeastward at a speed of 45–50 m/s. The maximum amplitudes of the sea-surface height during the low-pressure passing were up to twice larger than those directly converted from the ocean-bottom pressure without considering the effect of the atmospheric pressure. Our results suggest that the S-net with numerical simulations can detect the generation and propagation of meteotsunamis, which could not be achieved in the past when dense OBP networks were not available.