We carried out surveying on the shallow structure and faulted-stratum of the Haihe fault in Tianjin using acoustic surveying methods such as the single-channel seismic technique. The result shows that the method can o...We carried out surveying on the shallow structure and faulted-stratum of the Haihe fault in Tianjin using acoustic surveying methods such as the single-channel seismic technique. The result shows that the method can obtain satisfactory results in wide and deep river courses. It also shows that in the Tanggu area of Tianjin, the upper fault point of Haihe fault is about 30m beneath the river bed and the corresponding latest active period is Qp^3- Qh^1 , which is consistent with the former borehole survey result. In the offshore area of the Bohai Sea, Haihe fault shows as a NWW-NEE strike dense fault zone and its upper fault point is less than 30m beneath the seabed. It shows that the active characteristics of Haihe fault in the Bohai Sea correspond to the Tanggu area.展开更多
Buried object which exists at extremely shallow underground can be detected by using an acoustic vibration and a SLDV （scanning laser Doppler vibrometer）. Non-contact acoustic exploration can be realized by using ai...Buried object which exists at extremely shallow underground can be detected by using an acoustic vibration and a SLDV （scanning laser Doppler vibrometer）. Non-contact acoustic exploration can be realized by using air coupled sound. It was confirmed that discovery and the identification of a buried thing were possible using the OFR method （optimum frequency range method）. However, in this method, only the amplitude of the vibration speed spectrum is used and did not use the phase information. Therefore a new imaging method is proposed that used the phase information of the vibration speed spectrum. From the experimental results, the possibility of the outline extraction by using the phase difference between each scan point is confirmed. As a future task, the phase difference image will become clearer by changing the scan point density and long duration time of emitted wave.展开更多
Marine active fault exploration and paleoearthquake research are still a gap in China. The paper gives a review on major research methods and new progress made abroad, including submarine survey boat, seismic reflecti...Marine active fault exploration and paleoearthquake research are still a gap in China. The paper gives a review on major research methods and new progress made abroad, including submarine survey boat, seismic reflection and acoustic reflection. Through detailed studies of offset history of 10 ka to 30 ka, it is possible to determine paleoearthquake recurrent intervals and elapsed time since last major earthquake. It is suggested that active fault exploration can be carried out by acoustic exploring method in large earthquake region of Bohai Sea. Paleoearthquake activity history can be revealed and earthquake risk in the future can be predicted.展开更多
基金the China Digital Seismic Observation Network Program and the Active Fault Detecting Sub-program of the tenth"Five-Year Plan" of China Earthquake Administration
文摘We carried out surveying on the shallow structure and faulted-stratum of the Haihe fault in Tianjin using acoustic surveying methods such as the single-channel seismic technique. The result shows that the method can obtain satisfactory results in wide and deep river courses. It also shows that in the Tanggu area of Tianjin, the upper fault point of Haihe fault is about 30m beneath the river bed and the corresponding latest active period is Qp^3- Qh^1 , which is consistent with the former borehole survey result. In the offshore area of the Bohai Sea, Haihe fault shows as a NWW-NEE strike dense fault zone and its upper fault point is less than 30m beneath the seabed. It shows that the active characteristics of Haihe fault in the Bohai Sea correspond to the Tanggu area.
文摘Buried object which exists at extremely shallow underground can be detected by using an acoustic vibration and a SLDV （scanning laser Doppler vibrometer）. Non-contact acoustic exploration can be realized by using air coupled sound. It was confirmed that discovery and the identification of a buried thing were possible using the OFR method （optimum frequency range method）. However, in this method, only the amplitude of the vibration speed spectrum is used and did not use the phase information. Therefore a new imaging method is proposed that used the phase information of the vibration speed spectrum. From the experimental results, the possibility of the outline extraction by using the phase difference between each scan point is confirmed. As a future task, the phase difference image will become clearer by changing the scan point density and long duration time of emitted wave.
文摘Marine active fault exploration and paleoearthquake research are still a gap in China. The paper gives a review on major research methods and new progress made abroad, including submarine survey boat, seismic reflection and acoustic reflection. Through detailed studies of offset history of 10 ka to 30 ka, it is possible to determine paleoearthquake recurrent intervals and elapsed time since last major earthquake. It is suggested that active fault exploration can be carried out by acoustic exploring method in large earthquake region of Bohai Sea. Paleoearthquake activity history can be revealed and earthquake risk in the future can be predicted.
