ACKNOWLEDGEMENT I would like to respect Dr. Vu Thanh Tu, lecturer in Department of Hydrology and Water Resources, Thuy Loi University and Dr. Nguyen Quoc Khanh, a major Researcher of Vietnam Institute of Geosciences and Mineral resources, for their guidance, advice andexperience to complete this master thesis. Their constructive comments, untiring help, guidance and practical suggestions inspired me to accomplish this work successfully.
Besides, I would like to thank Propessors in Hydrology and Water resources faculty and members in the Project "Investigation, assessment and warning zonation for landslides in the mountainous regions of Vietnam” conducted by Vietnam Institue of Geosiences and Mineral resources (VIGMR) who supported me in terms of the data collection and gave me useful advices for my thesis. I remember all those who have contributed directly or indirectly to successfully completing my study. Finally, I must express my very profound gratitude to my family for providing me with unfailing support and continuous encouragement throughout my years of study and through the process of researching and writing this thesis. This accomplishment would not have been possible without them.
Ha Noi, May 23" 2017 Luu Thanh Binh DECLARATION Thereby declare that is the researches have done by myself under the supervisions of Dr. Vu Thanh Tu and Dr. Nguyen Quoc Khanh. The results and conclusions of the thesis are fidelity, which are not copy from any publish sources or any forms.
The references documents and relevant sources, the thesis has cited and recorded as prescribed. Ha Noi, May 23" 2017 Luu Thanh Binh ABSTRACT. In Viet Nam, there have not been so far comprehensive database of natural disasters in general as well as landslide in particular, Therefore, although there is an undebatable considerable achievements in landslide mitigation, these efficiencyhas not been significant, Consequently, thete is an urgent demand to have implementation of landslide investigation, In the scope of the State-funded Landslide Project “Investigation, assessment and warning zonation for landslides in the mountainous regions of Vietnam” funding by Vietnam institute of geosciences and mineral resources, an integrated methodology that combining the traditional investigation with modern technology of remote sensing imagery analysis has been applied and initially ‘generating encouragingly achievements. This methodology has extremely utilized the ‘available data and resources as well as applying stage of the art technology in order to support investigator in field survey.
Based on that, the most complete landslide database of characteristics along with causes resulting in landslide process has been established, Within scope of the topic 1g using GIS and field investigations on scale 1:50.000 in Tuong Duong district, Nghe An province” is conducted for further study on an integrated method sys m between traditional investigations with moder remote sensing technology has been applied and initially giVen good results. This system takes full advantage of available data and resources as Well as applies new technologies to assist investigators in carrying out their work in the field, Thanks to complete database on characteristics of sliding blocks, as well as its causes has been built, TABLE OF CONTENTS INTRODUCTION -osnosnnnnnninennninninnnnnnnmnnnnnnnnnnsnnrnne Overview. 1 Objectives and tasks.1 Types of landslides and causes.2 Factors affecting slides.2 World-wide researches on geological hazards 20 1.3 Researches on geological hazards in Vietnam, 23 CHAPTER 2.1 Process of mapping the current state of landslides 26 2.2 Field surveys 33 CHAPTER 3. DATA COLLECTION AND DATA ANALYSIS 3.
RESULTS AND DISCUSSIO: 4.1 The results of Landslide, interpretation from remote sensing data 31 4.2 Results of actual landslides survey work.3 The causes of landslides sẽ 4.1 Geomorphology, topography factors.3 Meteorological and hydrological elements 60 4.4 Causes from the impact of other types of geological hazards ol 4.5 Human activities “ CONCLUSIONS AND RECOMMENDATIO: REFERENCES. APPENDIX LIST OF TABLES Table 1. Vamas Sliding Classification System (1978, 1984) 6 ‘Table 2. Interpretation standardization of objects corresponding to landslide morphology, 3 ‘Table 3.
List of map sheet to be used into created DEM in study area 38 Table 3. Statistics number interpreted locations have signal of landslides on aerial imagery and terrain analysis on digital stereoscopic model at scale of 1: 10.000, and the number of checked sites in the field 33 Table 5. The statistic of landslide points’ number according to scale corresponding type of slope and land use in Tuong Duong district. 5s Table 6, The statistic oflandslide points’ number according to seale corresponding scale and type of landslide in Tuong Duong district 56 ‘Table 7.
The statistic oflandslide point's number causing damage in Tuong Duong istrict 56 LIST OF FIGURES Figure 1, Studied area (Tuong Duong distri he An province) 2 Figure 2. Showing different parts of landslide (USG: , 2009) and (Chakraborty, 2008)6 Figure 3. Falling slide (falling rocks) 1 Figure 4. Uptuming slide 8 Figure 5.
Rotational slides 9 Figure 6. Translational slides 10 Figure 7.Complex slide lô Figure8. Debris flow R Figure 9. Flank shape 16 Figure 10.
Conceptual framework 2 Figure 11. Stereoscopic for the same area created from aerial image (above) and satellite image (below) with DEM 28 Figure 12. Hill shade 29 Figure 13. a) Checking landslide interpretation in the field; b) Compared landslide interpretation with 3D model 32 Figure 14.
Outline of satellite image interpretation processing 40 Figure 15. Crack on road edge and slope. Cracks/ predicted slopes of sliding blocks in Tan Xa area 50 Figure 17. Comparison of interpretation sliding points with 3D digital modkl.
Expected landslide interpreting from remote sensing 5 Figure 19. Landslide type classification by commune administrative unit s4 Figure 20, Landslide frequency by commune administrative unit 35 Figure 21. Landslide volume classification by commune administrative unit 35 Figure 22. Investigated positions in the field 37 Figure 23.
Landslide inventory mapping for Tuong Duong district, Nghệ An province 58 ABBREVIATION use United States Geological Survey GDP Gross Domestic Product FDI Foreign Direct Investment DEM Digital Elevation Model BDRM Community-Based Disaster Risk Management ADPC Asia Disaster Preparedness Center INTRODUCTION Overview Landslide is one of most common types of natural disasters occurring in mountainous areas of Vietnam. Damage to people, facilities and environment caused by landslide is foflen more serious than current awareness and assessment of society. In general, studies on landslide have been applied on a large scale, implemented at a small scale, ‘and most of them only provide quantitative forecasting results. Up to now, there have ‘been no surveys, studies and warnings about landslide risk in sufficient detail to better serve prevention and mitigation of losses (Le Quoc Hung et al.
In order to ‘overcome these trictions, it is necessary to develop a comprehensive survey and analysis program that applies advanced and appropriate methodologies to assess and ‘give warnings about landslide effectively and timely for a 12 planning and management of natural disasters in the context of climate change (Tran Tan Van et al., 2002, Nguyen Xuan Khien et al, 2012, Le Quoc Hung et al., 2013, 2014), So far, Vietnam has not have a full database of natural disasters in general or landslides in particular. Therefore, prevention of natural disasters to minimize the ‘damage caused by landslide in recent years has not been effective although there have been many achievements. Therefore, investigation of landslide in mountainous areas of Vietnam is a very urgent task, Within scope of the topic "Landslide inventory mapping using GIS and field investigations on scale 1:50.00 in Tuong Duong district, Nghe An province” is conducted for further study on an integrated method system between traditional investigations with modern remote sensing technology hay been applied and initially given good results. This system takes full advantage of Available data and resources as well as applies new technologies 0 assist investigators in carrying out their work in the field.
Thanks to complete database on characteristics Of sliding blocks, as well as its eauses has been built Objectives and tasks - To study the application of integrated method system between GIS technology, remote sensing analysis and field survey for setting up landslide mapping, - To investigate landslide status, determine causes of landslide in Tuong Duong district, Nghe An province. = To make a landslide map at scale 1/50,000 in Tuong Duong district, Nghe An province Features of terrain, geomorphology and hydrology ‘Tuong Duong is a mountainous district in western part of Nghe An province with area of 2.812km2 with quite complex terrain, high mountain range and huge segments, =I borders Laos and Que Phong district in the north and northwest It borders Laos in the south and southwest ~ borders Con Cuong district in the east and southeast ~ It borders Ky Son District in the west. River networkin this area is quite erowded, including Lam river with a length of nearly 50 kms. Upstream of the Lam River is divided into two sub-branches of Nam Mo River inthe southwest and Nam Non River in the northwest, and a large basin in the north of the district.
Also there are also small streams s as Cha Ha River, Chang “Trang Stream, Nam Chon Stream, Khao Stream, Co Stream. These are both difficult for traffic in the area and potential risk for flash flood. Traffic, humanity ‘Traffic network in this area is underdeveloped ausing many difficulties for travelling, National highway 7A runs across the district, This is the main traffic network to connect the western area of Nghe An province with other parts of the region. In addition, provineial highway 487 conneets National Highway 7A and National Road 48 to other districts in the northwest of Nghe An province.
In addition to the above- mentioned roads, Lam River is also a major transport route, There are also inter- ‘commune roads, border roads, but generally the roads are very winding, many slopes, sloping height of 10 to 50m, easy to slip in rainy seasons. ‘The population of the district, 68,441 people, with 18 administrative unit including many ethnic groups such as Kinh, Thai, Hmong, Tay, Odu, Khomu, ete. The population density is unevenly distributed, mostly crowded in. Hoa Binh town area and along the National Highway 7.
The main occupations are small agricultural production, small scale production and trading. In addition, there are residential are that focus on commune centers and small clusters along the road. The H’Mong and Khomu ethnic groups mainly live in mountainsides, streams and river banks. They live in big villages or small villages with outdated lifestyles.
Culture and economy of these mountainous ethnic groups is still underdeveloped. Up to now, about two thirds of the population in the district have no access to national power network Climate Tuong Duong is directly affected by the climate in southwest of Nghe An province, characterized by tropical monsoon climate with two distinct seasons, Rainy seasons: {rom April to October. Dry seasons: from November to March of next year. Average temperature varies from C, there is 6 months which its temperature exceeds 23oC; Month with the highest temperature is July: 39-41°C; The month with the lowest temperature is January: 8°C ‘Average rainfall is 1,450 mm, but unevenly distributed in space and time (in Ca river upstream from Cua Rao upward, rainy seasons start and end in 3 months including ‘August, September and October, annual average rainfall is only 1,350 mm.
Ca river downstream from Cua Rao downward, rainy seasons start from July and end in September, annual average rainfall is over 2,000 mm ). Affected by a part of southwest wind (from Laos) appearing from April to August, causing dry and hot clmate in some areas of the district (Cua Rao area, Xa Luong ‘commune are considered as hottest area in Indochina), Geological features In this area, base rocks are mainly quart bars-sericite, sandstone, siltstone, sericite, clay shale in Ca river formation (03-S1,.), siltstone, Huoi Nhỉ clay shale formation ($2-DIi,), Nam Tam (D1-2n0, clay limestone, siliceous shale, clay shale in La Khe formation (Cly).