3:00 PM - 3:15 PM
[HTT20-06] Mapping of near surface S-wave velocity structure based on H/V spectral ratio of microtremor measurements in Kangori district, south of Mt. Tsukuba.
Keywords:Single station microtremor measurement, H/V spectral ratio, near surface, Mt. Tsukuba.
We have been conducting dense microtremor measurements in Kangori district and the southern flank of Mt. Tsukuba, Tsukuba City, Ibaraki Prefecture. The survey covered the area about 10 square km, 3 km EW by 3 km NS, and a total of 160 points.
A 3-component seismic data acquisition system (Atom) was used for the measurements. Horizontal to vertical spectral ratio (HVSR) was calculated at each measurement point and uploaded to an open geophysical database site named “SeisImager.com”.
The peak frequencies of HVSR in the survey area varied from 0.9 to 17 Hz, and showed characteristic features as follows; namely, relatively low peak frequencies were observed in the Kangori basin area, and it descended toward to west. Relatively high peak frequency points appeared at the margin and the southern flank of Mt. Tsukuba. We estimated S-wave velocity models from the HVSR curves. They were basically concordant with borehole data.
A 3-component seismic data acquisition system (Atom) was used for the measurements. Horizontal to vertical spectral ratio (HVSR) was calculated at each measurement point and uploaded to an open geophysical database site named “SeisImager.com”.
The peak frequencies of HVSR in the survey area varied from 0.9 to 17 Hz, and showed characteristic features as follows; namely, relatively low peak frequencies were observed in the Kangori basin area, and it descended toward to west. Relatively high peak frequency points appeared at the margin and the southern flank of Mt. Tsukuba. We estimated S-wave velocity models from the HVSR curves. They were basically concordant with borehole data.