相模湾における低周波雑音計測

抄録

For the purpose of monitoring deep seafloor environmental changes associated with a submarine earthquake swarm, a cabled observatory consisting of multidisciplinary sensors including a hydrophone was deployed by JAMSTEC at a depth of 1200 m off Hatsushima Island in Sagami Bay. By using the data obtained by the observatory, the relationship between surface weather changes and underwater ambient noise, especially the origin of low frequency noise lower than 100 Hz, was examined. As a result, the site effects on the noise characteristics obtained by the hydrophone, consisting of the surrounding topography and the water depth, became clear. It also became clear that the low frequency noise caused by an earthquake and a typhoon can be discriminately observed by the observatory. These results can be utilized for detecting fluctuation phenomena or precursors on the seafloor that are associated with earthquakes.