Research On Identification Of Active Tectonics In Heqing Basin Based On Remote Sensing Data And High Precision DEM Data

Influenced by tectonic activities, Yunnan and Sichuan areas in western of China were regularly shaken by earthquakes in recent years, so how to identify active tectonics quickly becomes a focus in the current research. With the development of remote sensing technology and the constant improvement of the accuracy of RS and DEM data, the active tectonic research has opened up a new field. In this paper, we select Heqing basin in Yunnan province as research area and SPOT5, Landsat8 and DEM from survey satellite “ZY-3” as main research data sources, the object-oriented classification and cluster analysis techniques are utilized to identify the main active geomorphology(such as proluvial fans and river terraces) in study area. Based on the work above, we extract lineament information which is associated with the distribution of the active geomorphology, and analyze the characteristics, nature and the relative active age of the tectonic activities. The main research achievements include as following:1. This paper discusses the current main methods of remote sensing topography recognition, the methods include traditional visual interpretation, pixel-based geomorphology recognition and object-oriented geomorphology recognition, and analysis the advantages, disadvantages and applicability of each method. What’s more, we use the stereo pair data of resource-III satellite generated high resolution DEM data, generate a variety of topographical factors such as aspect, slope, waviness, roughness, etc. And discuss the characteristics and applicable scale of each factors, for extraction active topography and active fault.2. This paper uses the object-oriented methods to classify the active geomorphology such as alluvial fan and river terraces, created the classification rules of alluvial fan and river terraces. According to the morphological characteristics, we use topographical factors which can be quantified to express alluvial fan and river terraces. We combine the classification scheme with the human experience, so we can flexibly classify the geomorphology. Based on the above, we design different linear structure information extraction method depend on the different type of fault of the study area.3. Based on the extraction results of the active tectonic information above and combining the previous research and field investigation, we analyze the distribution, active age and characteristics of the active tectonics in Heqing basin. The analysis results show that the active tectonics can be divided into SN-, NE- and NW-trending faults. Among them, the NS- and NE-trending faults have relatively high development degree and large scale, while the NW-trending faults have relatively low development degree and small scale. The latest active time of the NE-tending faults is later than the NS- and NE-trending faults in the north of the research area, and the NW-trending faults have signs of activity recently in the south. Moreover, the NE-trending faults in the whole basin have clear signs of activity since the Holocene.