無人ヘリによる口永良部島火口周辺域における地震観測点の再構築

Abstract

On August 3, 2014, a moderate eruption occurred at Kuchinoerabu-jima and all the observation stations at the summit area were destroyed. A summit eruption on May 29, 2015 caused entire evacuation of the island. In order to reconstruct the seismic observation network at the summit area, we newly developed seismometers suitable for the observation and conducted seismometer installations at the summit area by using an unmanned helicopter. Helicopter operations were conducted twice. 4 and 5 stations were installed in April and September 2015, respectively. The reconstructed seismic network could successfully detect the sudden increase and decrease in shallow earthquakes few days before the eruption in May 2015. Comparison of the April and September observations clearly shows the declined trend of volcanic activity