Using ambient noise correlation and the moving window cross spectrum method,we detected the variations in relative seismic velocity over approximately one year before and after the eruption of the Mt.Ontake volcano in Japan on September 27,2014,and Kilauea volcano in Hawaii,USA,on May 4,2018,respectively,using continuous seismic data collected from the Hi-net network and IRIS.The measurement results in the 0.4～0.8 Hz frequency band for the Mt.Ontake volcanic area show that the average relative seismic velocity decreased by about 0.1％during the 10 days before the eruption and then gradually recovered after the eruption.In the Kilauea volcanic area,the measurement results in the 0.5～1.0 Hz frequency band show that the average relative seismic velocity decreased by about 0.5％during the 10 days before the large-scale eruption and then grad-ually recovered after the eruption ended on 4 August 2018.Combined with the results of ground tilt,GPS,and focal mechanism solutions of the two volcanic areas,it is shown that the changes in relative seismic velocity before and after the volcanic eruptions are a response to shallow magmatic inflation and deflation processes in the volcanic areas.
关键词
背景噪声/日本御岳山火山区/夏威夷基拉韦厄火山区/相对波速变化/岩浆膨胀与收缩
Key words
Ambient noise/Mt.Ontake volcanic area in Japan/Kilauea volcanic area in Hawaii/Relative seismic velocity change/Magmatic inflation and deflation
维普
万方数据