Explosion Seismic Observations in the Central Part of the Kitakami Region, Northeastern Japan

Q and Site Amplification Factors of Hard-Rock Region in the Kitakami Massif, Northeastern Japan.

“…Solid line connecting S-H and S-S indicates the observation line of this study and dotted line the refraction line of RGES (1992). Hasemi et al (1994). The P-wave velocity of the second layer was estimated to be 5.88 km/s (average) or 5.80+0.09z km/s (.7 being the depth from the top of the second layer, in km).…”

“…Iwasaki et al (1993Iwasaki et al ( , 1994 obtained detailed velocity and Q structures in the crust beneath this profile. For this experiment, we set 20 stations on a 60 km E-W observation line crossing the RGES line, and observed explosions by the RGES and two explosions at quarries (Hasemi et al, 1994). The data used in this study are from three explosions, S-H, S-2, and S-S, detonated on the E-W line (Fig.…”

“…Clear S-waves were recorded for explosions at quarries. VP/VS was estimated to be 1.74-1.75 from the P-to S-wave travel time ratio (Hasemi et al, 1994).…”

“…3. P-wave velocity structure near the surface obtained based on time-term analysis by Hasemi et al (1994). Error bars denote standard deviation of estimated depth of the boundary.…”

“…We estimated the geometrical spreading function by calculating synthetic seismograms for a horizontally layered model derived from the result by Hasemi et al (1994). The thickness of the top layer was assumed to be 0.5 km.…”