Item

Abstract

Marine volcanoes, i.e., both above-surface- and submarine-volcanoes can be threat for human lives and social activities because of not only volcanic eruption itself but also they sometimes excite tsunamis. Long-term continuous monitoring is important to predict the eruptions, and therefore we attempt to measure the seafloor deformation near the volcanic island using an in-situ pressure sensor and some bench marks. The measurement period was to be five years and it is designed that the communication port is available to recover the measurement dataset whenever we access the pressure sensors during pressure calibration. The present target is Izu-Oshima Island, one of the Izu-Ogasawara (Bonin) volcanic chains, categorizing an active volcano. We calibrate the pressure sensor once a year and evaluate the deformation at the point of pressure sensor and the bench marks over time. To perform this concept, firstly we select a pressure sensor indicating small sensor drift based on the laboratory experiment pressurized by a pressure balance. Then, we have installed the pressure sensor at the seafloor near the island in 2021. The first in-situ pressure calibration was conducted in 2022 after one year of the first deployment of the pressure sensor. We recovered the dataset and confirmed the initial sensor drift. The second in-situ pressure calibration will be conducted in May of 2023 and it is not until that the sensor drift can be removed. In the presentation, we introduce the laboratory experiment and the in-situ pressure measurement during the first one-year observation.