千島海溝で発生する津波の後続波の特性に関する研究

抄録

We discuss the characteristics of the later-phase tsunamis accompanied with earthquakes along the Kuril trench, based on the numerical modeling of trans-oceanic tsunamis and the analysis of observed tsunami waveforms. The model results suggest that the later-phase tsunami is caused by edge waves or scattering waves from the seamounts, depending on the tsunami source location; tsunami energy radiated from south of 46° N can result edge waves andnorth of 46° N to 49°N can be scattering waves. Also, we found that analyzing the time evolution of Fourier spectra of observed tsunami waveforms can identify the cause of later-phase tsunamis and can be used to decide the timing of tsunami warning cancellation after it's issued.