LANDSLIDE HAZARD AND RISK ASSESSMENT FOR ROAD NETWORK USING RS AND GIS: A CASE STUDY OF XIN MAN DISTRICT, VIET NAM by Lai Tuan Anh A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering Examinat ion Committee: Dr Kiyoshi Honda (Chairperson) Dr Marc Souris Dr Ulrich Glawe Nationality: Vietnamese Previous Degree: Bachelor of Engineering in Geodesy Hanoi University of Mining and Geology, Vietnam Scholarship Donor: AIT Fellowship Asian Institute of Technology School of Engineering Technology Thailand May 2006 i ACKNOWLEDGEMENT It is with delight that the author first of all extends his hearties gratitude to the Thesis research committee Chairperson, DR Kiyoshi Honda for his professional guidance, advice, encouragement throughout the study The technical and conceptual support of Dr Marc Souris, thesis committee member, helped me to conduct the research for which I express my thanks to him Valuable suggestions support of Dr Ulrich Glawe and thesis committee member help me to work enthusiastically so I am grateful to him I would like to express my sincere thanks to DANIDA for the scholarship and Star program for the research grand, thereby making this study possible Special thanks go to RSL staff, Mr Do Minh Phuong for providing all the necessary on time I am grateful to the local in Xin Man province who provided and guide me go to all the landslide points to measurement GPS My vote of thanks goes to all my friends, Mr Tran Trung Kien, Miss Dao Thi Chau Ha, for their helps, supports, sharing the difficulties to my life in AIT Most of all, I want to express my deep appreciation to my family: Parents, my sister for their endless love, constant support and encouragement for the graduate study ii ABSTRACT Xin Man district in the South west Ha Giang has high landslide hazard However, the available information on landslide in Xin Man district is still limited We constructed the essential spatial database of landslides using GIS techniques The quantitative relationships between landslides and factor s affecting landslides are established by the Certainty Factor (CF) The affecting factors such as slope, elevation, landcover, geology, road distance, lineament distance, drainage density are recognized By applying CF value integration and landslide zonation, the most significant affecting factors are selected By using RS&GIS technology landslide occurrences on all these factors have been analyzed The vector based GIS has been used for digitizing to produce thematic maps, as analysis for study was based on the pixel based information therefore Raster based GIS has been used for the analysis Pixel based calculation was made by using the CF value Model By using the CF model we obtain the CF value for all classes al all factor maps On the basis of these CF value all factor maps are recoded and matrix analysis was perform to produce a Landslide Hazard Zonation map The Landslide Hazard Zonation map has been applied to develop a methodology to produce hazard maps considering the behavior of landslide and to evaluate potential damage to infrastructure specific road system Different factors have been cons idered for this study iii TABLE OF CONTENTS CHAPTER TITLE PAGE Title page ACKNOWLEDGEMENT ABSTRACT TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF MAPS LIST OF ABBREVIATIONS i ii iii iv vi vii ix x INTRODUCTION 1.1 Background 1.2 Statement of problem 1.3 Objectives 1.4 Scope and limitation 1 2 LITERARUTE REVIEW 2.1 Hazard, risk & vulnerability 2.2 Landslide Hazard mapping 2.3 Fundamental of Remote sensing 2.4 GIS overview 2.5 Global Positioning System (GPS) 2.6 Web Map Server 2.7 Landslide Studies 3 12 12 12 15 DESCRIPTION OF THE STUDY AREA 3.1 Area and situation 3.2 Climate 3.3 Rainfall 3.4 Population 3.5 Geology 3.6 Elevation 3.7 Slope 3.8 Lineament 3.9 Road system 3.10 Drainage density 3.11 Landcover 18 18 18 18 18 20 22 24 25 27 29 30 METHODOLOGY AND ANALYSIS 4.1 General 4.2 Compilation of Required data 4.3 Field Survey by using GPS 4.4 Extraction of maps from the source data 33 33 33 34 35 iv TABLE OF CONTENTS (CONT.) CHAPTER TITLE PAGE 4.5 Methodology and Analysis Data 4.6 Data Entry 4.7 Analysis data 4.8 Landslide Hazard Zonation Map 38 40 41 43 RESULTS AND DISCUSSIONS 44 5.1 Characterize several types of landslide in Xin Man district 44 5.2 Landslide Hazard Zonation map 46 5.3 Landslide Hazard Zonation map 54 5.4 Accuracy Check for Landslide Hazard Zonation Map 60 5.5 Develop a methodology to produce hazard maps considering the behavior of landslides 62 5.6 Publish Landslide Hazard Zonation to Internet using Web Map Server 69 CONCLUSIONS AND RECOMMENDATIONS 6.1 Conclusions 6.2 Recommendation 76 76 77 APPENDICES 80 v LIST OF TABLES TABLE 2.1 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 4.1 4.2 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 5.12 5.13 5.14 TITLE PAGE Landsat ETM image characteristic Geology, major litho-stratigraphic units with their corresponding classes Area under Geology Area under Elevation Area under slope Area under distance to lineament Area under distance to road Area under drainage density Area under Landcover Analysis data from different sources Hazard zones CF value of Geological CF value of distance to lineament CF value of slope angle CF value of elevation classes CF value of drainage density CF value of landcover layer CF value of distance to road The hazard value ranges used for road buffer The hazard value ranges used for whole area % area for landslide hazard zone for buffer area % area for landslide hazard zone for whole area Defining the risk Classification risk level Result of the risk class based on buffer analysis vi 20 21 22 24 26 27 29 30 34 43 47 48 49 51 52 53 54 55 55 56 56 64 66 69 LIST OF FIGURES FIGURE 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.1 4.2 4.3 4.4 4.5 4.6 4.7 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 5.12 5.13 TITLE PAGE Criteria for risk assessment (Disaster Preparedness and Mitigation-2002) Spectral reflectance of vegetation, soil and water Spectral reflectance of a green left The image interpretation processing Data Flow in Remote sensing The flow of geometric correction 10 Procedures of Classification 11 WFS Processing Request 14 Map of large Landslide areas of Vietnam 17 The yearly rainfall from 1961 to 2003 18 Location of Study area Xin Man district, Viet Nam 19 Geology chart 21 Elevation chart 23 Slope chart in Xin Man district 24 Distance to the lineament chart 26 Road area under the buffer 28 Drainage density chart 29 Landcover chart 31 Flo w Diagram For Landcover Map 35 Flow Diagram for Digitized Map 35 Flow Diagram for Landslide Map using GPS 36 Flow Diagram For TIN and maps extraction from TIN 37 Flow Diagram For Landcover Map extracted From Satellite Data 37 Flow Diagram for Buffered Road and lineament Maps 38 Methodology of thematic data layer preparation 39 Show the landslide attacked road 44 Wedge slip occur along the road 45 CF value of geological 48 CF value of distance to lineament 49 Statistical map of slope angle distribution in Xin Man District 50 CF value of slope angle layer 50 CF value of elevation layer 51 CF value of drainage density layer 52 CF value of landcover layer 53 CF value for distance road 54 Bar chart showing the distribution of various hazard zones 57 for buffer area in Xin Man district 57 Bar chart showing the distribution of various hazard zones for whole area in Xin Man district 57 Relative distributions of various hazard zones and landslide probability within each zone in road buffer in Xin Man district 60 vii LIST OF FIGURES FIGURE 5.14 5.15 5.16 5.17 5.18 5.19 5.20 5.21 5.22 5.23 TITLE PAGE Relative distributions of various hazard zones and landslide probability within each zone whole area in Xin Man district The description of the road buffer Show the process landslide Schematization the Landslide area Flow chart fo r procedure risk map Minnesota Mapserver Framework Using CGI Input data from the Mapfile Study area on WMS LHZ map in Xin Man on MapBrowser LHZ map on GMapFactory viii 61 62 63 63 64 70 73 74 74 75 LIST OF MAPS MAP 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 5.1 5.2 5.3 5.3 5.4 5.5 5.6 TITLE PAGE Tin in Xin Man district Geological in Xin Man district Elevation in Xin Man district Slope in Xin Man district Distance to lineament in Xin Man Buffer road system in Xin Man Drainage density in Xin Man Landcover in Xin Man Road system in Xin Man Landslide distribution in Xin Man district Landslide hazard zonation for buffer area in Xin Man Landslide hazard zonation for buffer area in Xin Man Risk of slope in Xin Man’s Road Network Risk of distance to Xin Man’s road network Risk in Xin Man Risk assessment for road network in Xin Man ix 19 22 23 25 27 28 30 31 32 46 58 59 65 65 67 68 LIST OF ABBREVIATIONS TIN Triangulated Irregular Network DEM Digital Elevation Model DTM Digital terrain Model RS Remote Sensing GIS Geographical Information System GPS Global Position System GML Geographical Mark Up Language JPEG Join Photographic Experts Group URL Uniform Resource Locator WWW World Wide Web WMS Web Map Service WFS Web Feature Service x Objective 3(cont.) • Divided road by sections depend on the topology, types of road, and risk map • Conversion road to raster and overlay to the risk map to calculate sum up the pixel along the road per classes • Assign the weight for all classes in the sections • After that we get the weight final for all the sections • Weight = (number of pixel in class * 5)+ (number of pixel in class * 4)+ (number of pixel in class * 3)+ (number of pixel in class * 2)+ (number of pixel in class * 1))/Total pixel • Classify to risk classes Objective Weight = (number of pixel in class * 5)+ (number of pixel in class * 4)+ (number of pixel in class * 3)+ (number of pixel in class * 2)+ (number of pixel in class * 1))/Total pixel Defining the risk Classification risk class Validation risk assessment Objective Overview methodology Conclusions • The result of CF value integration and landslide hazard zonation, key affecting factors are define, which provide useful information for identifying different levels of landslide hazard • Application of GIS was found immensely useful for thematic data layer generation and for their spatial data analysis, which involved complex operation • This district needs urgent attentions in the form of mitigate measure like regeneration of natural vegetation, reforest station, drainage correction and restriction of seasonal tilling activity and contour bunding to ensure proper drainage etc • The construction must be carried out far away zones which id dangerous areas such as high hazard to very high hazard • Furthermore, factor maps derivative maps complied from a variety of data sources Therefore, the precision and accuracy of the derivative map depended on the original data scale transformation and the process of map compilation Recommendations • Integration of Aerial photograph with GPS survey give more accurate and widely distributed map of landslide • Weight, to each factor map according to importance, can be given for developing a landslide hazard map • Landslide risk evaluation can be made by considering the settlement of study area • Accuracy of CF value model can be check by a statistical approach • In this study, we only apply WMS to publish LHZ map on internet, if we have more time, we will write more and adding all information about landslide Moreover, we will create attribute table to update all information ... in Xin Man Landcover in Xin Man Road system in Xin Man Landslide distribution in Xin Man district Landslide hazard zonation for buffer area in Xin Man Landslide hazard zonation for buffer area... distance to road The hazard value ranges used for road buffer The hazard value ranges used for whole area % area for landslide hazard zone for buffer area % area for landslide hazard zone for. .. Distance Landcover Independent data layers(categorical) DATA INTEGRATION Geological map Landslides map Lineament map Landslides map Elevation map Landslides map Slope map Landslides map Drainage