Abstract
We observed long-period seismic waves excited by eruptions in 2014 and 2015 at Kuchinoerabujima Volcano, Japan. The propagations of seismic waves were clearly recognized in F-net seismograms in southwest Japan. The excitation force of three eruptions was analyzed using F-net broadband seismometers. The analysis of source time functions of three-component single force shows that vertical force is dominant in the eruptions at 12:24 on Aug. 3, 2014, and at 12:09 on May 29, 2015 (local time). In addition to the vertical force, lateral force in the north-south direction was also dominant in the eruption at 9:59 on May 29, 2015. This suggests that the mechanism of this eruption is different from the other two eruptions. The lateral force may be related to the momentum exchange by the emission of deposits inclined to the north- south direction.
