11:15 AM - 11:30 AM
[SCG52-09] High-frequency later phases for intraslab earthquakes and attenuation in the mantle wedge beneath northeastern Japan
Keywords:Intraslab earthquakes, Later phases, Seismic attenuation, Scattering
This analysis carried out in five frequency bands; 1-2, 2-4, 4-8, 8-16, and 16-32 Hz. In higher frequency bands (8-16 and 16-32 Hz), the later phase is obviously observed and often mark the maximum amplitude. In the frequency band, peak amplitude delays could be modeled as a wave detouring beneath the forearc region. These results suggest that the high-frequency later phases propagate avoid the mantle wedge which has strong attenuation, as discussed in Hasemi and Horiuchi . Additionally, the results suggest that the later phase may also be recorded in 4-8 Hz. In seismograms (4-8 Hz), the later phase seems to be recorded occasionally as the second peak of amplitude. Therefore, investigations of this frequency-dependence of the later phases and comparisons amplitude between the direct waves and the later phase would improve understandings of seismic attenuation in the mantle wedge and short wave-length structures beneath northeastern Japan.