Debris Flow Monitoring Technology After Earthquake

Debris Flow is one of the most destructive mountain disasters, and widelydistributed in mountain areas.With the rapid development of social economy and theincreasing strength of human activities, debris flow disasters occurre more and morefrequently under the impetus of the global climate deterioration.The harm degree hasbecome a threat to people’s life and property safety of the disaster area and prominentproblems of restricting the development of society and is increasingly serious.Monitoring and prediction Landslide disaster is one of important non-engineeringmeasures in the prevention and mitigation debris flow disaster. The resaerch aboutmonitoring and forecast warning of secondary landslide disaster in post-earthquake isrelatively few. Therefore aiming at this problem, this paper studies the monitoringtechnology of debris flow disaster. It set up monitoring and prediction technology andmethod system to fit for earthquake areas and characteristics of debris flow disaster.And taking the Niuquan ditch river basin in Wenchuan earthquake epicenter as thetypical study area, it completed the monitoring and prediction technique research ofdebris flow disaster. This method meets the reality needs of the prevention andmitigation of earthquake disaster area and has important realistic and scientificsignificance. The main results:1. Building the disaster monitoring technique method system suited thecharacteristics of the secondary debris flow disaster earthquake. From RS and theperspective of disaster monitoring, the monitoring content, principle and method ofthe secondary debris flow disasters after an earthquake are summarized system andthe key technology of secondary mountain geological disaster monitoring aresummarized. Base on this, take secondary mountain hazard monitoring using RS onlarge area at Niujuan Ditch, and situ monitoring at Niujuan Ditch. Then, analyze thespatial distribution and evolution features of debris flow.2. Combined with the basic geographic data, field survey data and GIS technology,analyze the morphology and image features, and compare it with the surroundingpregnant environment, image and spectroscopy differences using multi-sourcetemporal access high-resolustion remote sensing data. Establish remote sensinginterpretation signs of secondary geological disasters. Proposed secondary geologicalhazards identification and diagnositic techniques based on spectral features, imagecharacteristics and pregnant environment. Realize secondary geological disastersautomatic identification and information extraction.3. Preliminarily analyze the secondary mountain hazards distribution andevolution features in Nujuan Dith. Under strong earthquake, landslides in the studyarea is mainly distributed in a ditch on the left main basin, with a elevation1.4-2.2kmmiddle mountain area, slope35°~50°area, sunny slopes (east, south, southeast andsouthwest) frequency of occurrence of landslides are higher than shady slope (west,north, northeast and northwest).the greater the distance from the water, the weaker itsdistribution and activity, and mountain hazaards decreas with negative powerexponentially law. Secondary mountain hazards are still active after the earthquake, the whole of landslide has been a state of creep,the overall deformation rate to an ave-rage of1.788mm/d;Epicenter collapsed activities are mainly concentrated in theupper part of the body, and is more severe, which provide a rich provenance for debrisflow. The next5-10years is still the focus of disaster prevention and mitigation.4. The long-term field meteorological monitoring results show that rodeo ditch is atypical rainstorm distribution area.Rainfall mainly concentrated in the May toSeptember, especially the high-intensity rainfall concentrated in July to August.Heavy rainfall induced secondary mountain disasters after the earthquake mostlyconcentrated in the July to August.