Whether the surface rupture of the south segment of Minjiang fault is present remains a controversial issue in recent years. In previous work, interpretation of remote sensing images from Google suggests that this fault section exposes on slopes of the eastern bank of the Mingjiang River, expressing as surface ruptures, implying its activity during Holocene. While the features of fault scarps seen in the field challenges the existence of these ruptures. By virtue of exhaustive field investigations, this paper attempts to further address this issue. Our analysis of geology and geomorphology suggests that the topographic characteristics from remote sensing data are not traces of surface ruptures, instead resulted from a big landslide at the river. Thus it reminds us that there may be a great uncertainty when using remote sensing images interpretation to infer surface ruptures associated with faults.
In this paper, P5 stereo images and GeoEye-1 image are firstly processed and analysed in order to extract Digital Elevation Model (DEM) and divide stratum. The perpendicular Root Mean Square error of extracted DEM is within 5m in residual elevation report using methods of check point and visual inspection. According to the stratum division, measure points which are located at boundary or inner stratum are chosen at regions with better triangular facet of rock and st1able attitude, and then the attitude of stratum is extracted using three-dimensional data of the measure points through programming in MATLAB environment based on three-point method or multiple-point fitting method. Based on field survey, the measurement residual of dip angles is within 6 degrees, 85% less than 4 degrees. and those intermediate less than 3 degree. At the same time, seasons of residual generation are concluded, including geological structure, topography, accuracy of DEM, matching degree of DEM and images, the location of chosen point and so on. It is suggested that the method of attitude extraction using P5 stereo images and GeoEye-1 image is less restricted by worse natural conditions. Not only can the method restricts the profile of shallow tectonics, but also can cover the shortage of attitude of stratum, and have great significance for reducing uncertainty of Kalpin thrust tectonic deformation research. It provides a new way for quantitative research of Structural Geology, and also provides references for similar regions.
As the scientific investigation on the Ms8.0 Wenchuan earthquake demonstrates, the landscapes of co-seismic surface
ruptures or structure destructions were rapidly destroyed by storms or secondary disasters. Traditional survey methods
often are limited by the environment and do not provide perfect information about the deformation value in a timely
manner. The 3D laser scanner, on the other hand, can work under varying light conditions and does not require contact
with the destroyed objects. Its prompt completion of a pan-shot makes it possible to efficiently record a wealth of
information about the earthquake deformations, ensuring the quantitative analysis of related data. Its disadvantages
include costliness, unwieldiness and high-temperature-environmental inadequacy, etc.
In this paper, focusing on some examples, we explore the characteristics of 3D laser scanning technology used in the
micro-geomorphology survey and discuss its advantages and limitations. We also describe the data processing methods
and results. This includes the deformation values of the co-seismic surface ruptures or the merged impressions by 3D
scanning data and full view photo. In conclusion, 3D laser scanning has a wide range of prospects in
micro-geomorphology surveying and earthquake investigation. We then make some proposals such as using wireless
transmission that can improve its environmental adaptability.