The depth of upper fault point is the key data for ascertaining the active age of a buried fault on a plain. The difference of depth obtained from same fault may be dozens to several hundred meters when using differen...The depth of upper fault point is the key data for ascertaining the active age of a buried fault on a plain. The difference of depth obtained from same fault may be dozens to several hundred meters when using different geophysical methods. It can result in the absolutely opposite conclusions when judging fault activity. Because of a lack of an artificial earthquake source with wide band and high central frequency, many kinds of methods have to be used together. The higher the frequency of the artificial earthquake wave, electromagnetic wave and sonic wave, the higher the resolution. However the attenuation is also very fast and the exploration depth is very shallow. The reverse is also true. The frequency of artificial seismic waves is in the tens of Hz. Its exploration depth is big and the resolution is poor. The frequency of radar electromagnetic waves is about a million Hz, indicating that the resolving power is better, but the exploration depth is very shallow. However, the acoustic frequency is thousands of Hz, its resolving power is better than that of the artificial earthquake method and the exploration depth is larger than that of the radar method. So it is suitable for extra shallow exploration in the thick deposit strata of the Quaternary. The preliminary results detected using the high frequency acoustic method in extra shallow layers indicates that previous inferences about some fault activity in the eastern part of the North China plain may need to be greatly corrected.展开更多
Based on the biological resources surveys in China’s exclusive economic zone, the paper discusses the application of the GIS technology in evaluating the marine environmental quality, establishes the basic concept an...Based on the biological resources surveys in China’s exclusive economic zone, the paper discusses the application of the GIS technology in evaluating the marine environmental quality, establishes the basic concept and technological process for evaluating the environmental quality of the habitats of marine living resources, proposes the key points for the establishment of the relevant evaluation attributes database by applying the GIS technology and analyses several typical evaluation models and the data interpolation method for the model in GIS. Results show that the combination of the GIS technology with the quantitative evaluation model can be applied to the fast and accurate evaluation of the marine environmental quality.展开更多
文摘The depth of upper fault point is the key data for ascertaining the active age of a buried fault on a plain. The difference of depth obtained from same fault may be dozens to several hundred meters when using different geophysical methods. It can result in the absolutely opposite conclusions when judging fault activity. Because of a lack of an artificial earthquake source with wide band and high central frequency, many kinds of methods have to be used together. The higher the frequency of the artificial earthquake wave, electromagnetic wave and sonic wave, the higher the resolution. However the attenuation is also very fast and the exploration depth is very shallow. The reverse is also true. The frequency of artificial seismic waves is in the tens of Hz. Its exploration depth is big and the resolution is poor. The frequency of radar electromagnetic waves is about a million Hz, indicating that the resolving power is better, but the exploration depth is very shallow. However, the acoustic frequency is thousands of Hz, its resolving power is better than that of the artificial earthquake method and the exploration depth is larger than that of the radar method. So it is suitable for extra shallow exploration in the thick deposit strata of the Quaternary. The preliminary results detected using the high frequency acoustic method in extra shallow layers indicates that previous inferences about some fault activity in the eastern part of the North China plain may need to be greatly corrected.
文摘Based on the biological resources surveys in China’s exclusive economic zone, the paper discusses the application of the GIS technology in evaluating the marine environmental quality, establishes the basic concept and technological process for evaluating the environmental quality of the habitats of marine living resources, proposes the key points for the establishment of the relevant evaluation attributes database by applying the GIS technology and analyses several typical evaluation models and the data interpolation method for the model in GIS. Results show that the combination of the GIS technology with the quantitative evaluation model can be applied to the fast and accurate evaluation of the marine environmental quality.
