[SSS16-P11] Seismic wave attenuation and local depth of seismogenic layer in the crust beneath Kyushu, Japan
Keywords:seismic wave attenuation, seismogenic layer
In all the studied area, intrinsic attenuation dominates over scattering attenuation at low frequencies (1-2 Hz), whereas scattering attenuation predominates at higher frequencies (> 2 Hz). The results show strong spatial variations in scattering and intrinsic attenuation that depend mainly on the tectonic setting. Areas with strong scattering and intrinsic attenuation geographically correlate with the locations of the volcanoes and active faults.
We compare the relationships between scattering attenuation and intrinsic attenuation quantitatively in the typical tectonic settings, volcanoes and active faults. Areas with relatively strong scattering attenuation correspond to the volcanoes, while area with relatively strong intrinsic attenuation correspond to the active faults. We also compare the scattering attenuation and intrinsic attenuation with local cut off depth of inland earthquakes, D90 defined as the depth, above which 90% of the earthquakes occur [Matsumoto et al., 2016]. Areas with relatively strong scattering attenuation correspond to shallow seismogenic layers. The areas geographically correlate with volcanoes.
This work was partly supported by JSPS KAKENHI Grant Number JP15J40067.