5:15 PM - 6:45 PM
[SVC29-P09] Research and development for observation and monitoring of submarine volcanoes
Keywords:submarine volcanoes, Sofu seamount
Observations of submarine volcanoes are known to be extremely difficult compared to observations of onshore volcanoes. This is because satellite observations, which are commonly used in recent volcano observations, do not work under the sea surface. Even if the same kind of observations could be made for submarine volcanoes as for onshore volcanoes, the cost would be much higher than for onshore volcano observations. This talk introduces the research and development activities of JAMSTEC on submarine volcano observations, using as an event for earthquake and tsunami that occurred at offshore of Torishima Island last year.
After October 2, seismic activity near Torishima Island was active, and on October 9, a 0.6 m tsunami reached Hachijojima. The tsunami was much larger than expected from the magnitude of the earthquake, which caused a debate about the mechanism of the tsunami. Furthermore, aircraft observations by the Japan Coast Guard confirmed pumice rafts near Tori-shima Island. Therefore, JAMSTEC performed to identify the location of the earthquake and tsunami. Based on the respective tsunami and hydroacoustic wave data obtained from the seafloor observation network, the source was identified as the area around Mt. Therefore, we conducted an emergency survey cruise targeting the area around Mt. During the expedition, we found traces of recent volcanic activity in the caldera volcano in the central part of Sofu seamount. Simulation of drifting pumice rafts indicated that the source of the pumice was located north of Torishima Island.
Since it is difficult to monitor volcanic earthquake activity in the ocean due to expensive cost, DAS observations using optical cables laid on the seafloor for communication business are effective. JAMSTEC has conducted research and development using optical communication cables in Mishima Village, Kagoshima, targeting the Kikai submarine caldera volcano. As the next step, we have begun to observe volcanoes in the Izu Islands, including Izu Oshima and Miyakejima, for monitoring of volcanic activity, using optical cables laid in the Izu Islands.
After October 2, seismic activity near Torishima Island was active, and on October 9, a 0.6 m tsunami reached Hachijojima. The tsunami was much larger than expected from the magnitude of the earthquake, which caused a debate about the mechanism of the tsunami. Furthermore, aircraft observations by the Japan Coast Guard confirmed pumice rafts near Tori-shima Island. Therefore, JAMSTEC performed to identify the location of the earthquake and tsunami. Based on the respective tsunami and hydroacoustic wave data obtained from the seafloor observation network, the source was identified as the area around Mt. Therefore, we conducted an emergency survey cruise targeting the area around Mt. During the expedition, we found traces of recent volcanic activity in the caldera volcano in the central part of Sofu seamount. Simulation of drifting pumice rafts indicated that the source of the pumice was located north of Torishima Island.
Since it is difficult to monitor volcanic earthquake activity in the ocean due to expensive cost, DAS observations using optical cables laid on the seafloor for communication business are effective. JAMSTEC has conducted research and development using optical communication cables in Mishima Village, Kagoshima, targeting the Kikai submarine caldera volcano. As the next step, we have begun to observe volcanoes in the Izu Islands, including Izu Oshima and Miyakejima, for monitoring of volcanic activity, using optical cables laid in the Izu Islands.