Application Of Multi-source Remote Sensing Information On Extraction Of Active Fractures In The Northeast Of Hainan

The occurrence of earthquakes is closely related to the distribution of active faults,and remote sensing images not only show the whole picture of active faults and other activities,but also reveal the image information of fault activity,which provides an important reference for the analysis of the relationship between active faults and earthquakes.There are many active faults in Lei Qiong area and quaternary volcanic activities are intense.The magnitude7.5 earthquake in Qiongzhou in 1605 was one of the few major earthquakes in southern China,and the two earthquake-resistant faults of the earthquake were located in the northeastern region of Hainan.So the use of remote sensing data on active fractures in northeastern region of Hainan is of great significance.In addition to the widely distributed large faults in the Qiongbei area,the distribution of other small faults in the Qiongdongbei and the nature of its activities need to be further proved.The study area is seriously covered by the Quaternary loose sediments,the whole elevation is low,the vegetation is lush,the surface water system is developed and the active faults are developed.The human eye can not identify the fault traces from the simple ground color.So through the high spatial resolution of the remote sensing image to the study area micro-topography recognition is also facing this obstruction,in this time,hyperspectral resolution of the image can play a more effective role,through repeated tests to select the most effective image enhancement processing methods,expanding the difference between different strata and features,extracting hidden weak abnormal information,identifing the specific distribution of active fracture location.In this paper,TM,ETM +,OLI,SPOT6 and ASTER GDEM2 as the main data sources,based on the data preprocessing,through the remote sensing data to do color synthesis,principal component analysis,tasseledcap transform,band ratio and other image enhancement processing to obtain the most effective fracture image feature.Secondly,based on the comprehensive analysis of the geological and geomorphological features of the active faults in the remote sensing image,combined with the existing research results,establishing the interpretation signs of the active fracture to figure out the spatial distribution of the active faults.Using field geological survey,geophysical exploration and borehole profile to obtain geometric and motion characteristics of the active fractures.The activity rupture in the study area is mainly obtained through the interpretation of the color,topography,soil vegetation and water distribution.After the remote sensing interpretation and field verification,the spatial distribution and fracture properties of the main active faults in the Qiongdongbei are initially determined.The NNW and near-EW faults constitute the main tectonic pattern of the northeast of Qiongdongbei,and both are descending on the upper plate and rising in the upper deck.EW Guangcun-Puqian fault and NNW Puqian-Qinglan fault are main activie fractures of study area,the latest active were in Holocene;The rest fractures all actived during the Quaternary.