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| | Abstract | | I reprocessed the Nakagawa line data, the very shallow seismic reflection surveys conducted in November 2005. The surveys were conducted across the southeastern part of the Kego fault along the Nakagawa river using both P-wave, a drop-hitter, and S-wave, plank striking by a wooden sledgehammer. In both surveys we used a 48-channel landstreamer system. The source and receiver spacing is 1m, except for the some part of P-wave survey, where the source spacing is 2m. Frequency ranges of the lower limit for reprocessing are lowered compared with the previous processing and the ranges are 5-60Hz for S-wave and 40-600Hz for P-wave. By aplying F-X deconvolution, the first break of P-wawe became easy to pick. This resulted in better statics. Mainly by these things, the reflection events continuity was inproved. In the northern part of the survey line the strong event exists at about 20-30m in depth. It decreases the depth in the middle of the line from CMP no. 1100 through 1200 to near the surface with about 15m difference. This suggests that Kego fault may crosscut this part of the survey line. Other faults are interpreted checking the both P and S-wave depth sections. |
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