Response of the underground environment of the KAGRA observatory against the air-pressure disturbance from the Tonga volcano eruption on January 15th, 2022

TL;DR

This study investigates how the 2022 Tonga volcano eruption's air-pressure disturbance affected the underground environment of the KAGRA gravitational wave observatory, using environmental sensors to analyze transfer functions from atmospheric pressure to underground seismic and air pressure variations.

Contribution

It provides the first detailed analysis of the underground environmental response to a distant volcanic eruption using KAGRA's sensors, revealing transfer functions from atmospheric pressure to underground disturbances.

Findings

Transfer functions from air pressure to underground seismic motion identified.

Environmental sensors detected the eruption's impact inside and outside the facility.

Insights into underground environmental response to distant atmospheric disturbances.

Abstract

On January 15, 2022, at 04:14:45 (UTC), the Hunga Tonga-Funga Ha'apai, a submarine volcano in the Tongan archipelago in the southern Pacific Ocean, erupted and generated global seismic, shock, and electromagnetic waves, which also reached Japan, situated more than 8,000 km away. KAGRA is a gravitational wave telescope located in an underground facility in Kamioka, Japan. It has a wide variety of auxiliary sensors to monitor environmental disturbances which obstruct observation of gravitational waves. The effects of the volcanic eruption were observed by these environmental sensors both inside and outside of the underground facility. In particular, the shock waves made it possible to evaluate the transfer functions from the air pressure wave in the atmosphere to the underground environmental disturbances (air pressure and seismic motion).