On the study of high resolution electromagnetic prospecting using the wave field transfomation

点击翻译按钮获取中文摘要

The summary of results of the study is as follows ;1. I have studied the wave field transfomation with the spline approximation. I specially paid attention to number of terms and sampling interval in the spline approximation. A peculiar oscillation was sometimes appeared in initial part of the pseudo wave field after this transformation. It seems this was result in the numerical inverse Laplace transformation. The oscillation depends on the sampling interval in the approximation.2. I have computed transient vertical magnetic field for layred earth model and its pseudo wave field. The direct wave was detected in the wave field at the time expected from the wave theory. But, the refractive and reflective waves were not clearly detected at expected time because amplitude of these waves are much less than that of direct wave.3. A field test survey was carried out at Yuhuin area, Oita prefecture using the flux gate magnetometer attached with four sensors and the transmitter purchased by the grant. It was clear that this type of instrument was effective to detect the signal and reject of noise. The result was suggested that possibility of noise rejection using signal reference among the data at several sites. The result of survey showed that transient response of vertical magnetic field varied clearly at the Yufuin fault bounded by the Yufuin basin.