| Budget Amount *help |
¥18,330,000 (Direct Cost: ¥14,100,000、Indirect Cost: ¥4,230,000)
Fiscal Year 2014: ¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000)
Fiscal Year 2013: ¥7,020,000 (Direct Cost: ¥5,400,000、Indirect Cost: ¥1,620,000)
Fiscal Year 2012: ¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
|
|---|
| Outline of Final Research Achievements |
We developed a borehole seismic source for shallow structure survey. The source generates seismic waves by rotating eccentric masses controlled by motors. The radius of the source is 80 millimeters so that we can use it in standard boreholes for engineering survey. From the result of the field experiment, we concluded that the source generates controlled signals up to 50 Hz, and that the signal is observed at the seismic stations loocated at 50-200 meters from the source with good S/N ratio. A linear vibration in horizontal direction is achieved by rotating two motors in opposite directions, resulting in verification that the efficient transmission of P-wave and S-wave is possible. On the other hand, we found some technical problems for further improvement. We developed a series of data processing flow from the continuous seismic signal observed at the seismic stations to the S-wave velocity structure using S-wave traveltime tomography.
|
