|
| | Abstract | | In studies such as the source mechanism and S-wave polarization anisotropy, it is essential that accurate azimuth information of the seismograph. Also, it is necessary to consider the installation azimuth of two seismographs as for the site response analysis based on seismic records of a surface and an underground seismograph. We developed a simple method to estimate the orientation of an underground seismograph. A relative azimuth was presumed by setting up the surface seismograph near the pithead of the underground seismograph, and using the long-period component of surface and underground micro-tremors. It was confirmed to change the installation azimuth of the surface seismograph into three stages (0 degrees, 10 degrees, and 20 degrees), to presume the gap of the azimuth with an underground seismograph, and to obtain a prescribed value. When an underground seismograph rotated greatly, it was possible to readjust by confirming the azimuth by using the developed method. Because the azimuth of an underground seismograph can be immediately presumed on the site, it is thought that the developed method is useful for the installation of an underground seismograph. |
|
|
|
| |
|