10:00 AM - 10:15 AM
[SSS07-05] Long Period Signal Associated with the 2022 Hunga-Tonga Hunga-Ha'apai Eruption Observed at CEORKA Strong Motion Network
Keywords:Eruption at Tonga, Strong motion
The largest eruption of the Hunga-Tonga Hunga-Ha‘apai (HTHH) volcano, Tonga, began at 0415 UTC on 15 January 2022. This eruption of the underwater volcano excited a massive atmospheric pressure wave, which caused numerous geophysical phenomena globally. We have seismic records at CEORKA, Japan, strong motion network associated with this pressure wave. In this talk, we discuss the characteristics of these records using an atmospheric pressure record in this region
CEORKA is a strong motion network in the greater Osaka area. Each station is equipped with a three-component velocity-type sensor located near the ground surface. We have recordings at 24 stations. We are aware that the characteristic frequency of the observation is lower than the nominal frequency range of the sensor. We obtain displacement records by numerically integrating the velocity after the baseline correction.
The amplitudes of the horizontal components are larger than that of the vertical, and correlations between the two horizontal components are high. The apparent propagation velocity of the ground motion is as slow as the velocity of the Lamb wave. These imply that the observed signal is the record of ground deformation and tilt caused by the atmospheric pressure wave from Tonga. When we assume the long wavelength of the pressure wave, we can explain the characteristics of the seismic signal with the atmospheric pressure record in Kyoto.
CEORKA is a strong motion network in the greater Osaka area. Each station is equipped with a three-component velocity-type sensor located near the ground surface. We have recordings at 24 stations. We are aware that the characteristic frequency of the observation is lower than the nominal frequency range of the sensor. We obtain displacement records by numerically integrating the velocity after the baseline correction.
The amplitudes of the horizontal components are larger than that of the vertical, and correlations between the two horizontal components are high. The apparent propagation velocity of the ground motion is as slow as the velocity of the Lamb wave. These imply that the observed signal is the record of ground deformation and tilt caused by the atmospheric pressure wave from Tonga. When we assume the long wavelength of the pressure wave, we can explain the characteristics of the seismic signal with the atmospheric pressure record in Kyoto.