Master Thesis Submitted Within the UNIGIS Msc
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Master Thesis submitted within the UNIGIS MSc. programme at the Department of Geoinformatics - Z_GIS University of Salzburg, Austria under the provisions of UNIGIS joint study programme with Kathmandu Forestry College, Kathmandu, Nepal GIS Approach to Map the Levels of Earthquake Vulnerability of Buildings in Some Areas Effected by 2015 Earthquakes in Nepal by Nishanta Khanal GIS_104466 A thesis submitted in partial fulfilment of the requirements of the degree of Master of Science (Geographical Information Science & Systems) – MSc (GISc) Advisor (s): Dr. Shahnawaz University of Salzburg, Austria Kathmandu, 20.11.2017 i Science pledge By my signature below, I certify that my project report is entirely the result of my own work. I have cited all sources of information and data that I have used in my project report and indicated their origin. Kathmandu, Nepal 20-November-2017 Place and Date Signature ii Acknowledgements I express my sincere gratitude to my supervisor Dr. Shahnawaz for his guidance without whom the project could not have been accomplished. I am also grateful towards Mr. S. Pradhan (NSET BCIPN) who introduced me to the Building Inventory Data Survey which led me to work on this project. I am equally grateful towards other NSET staffs involved in the survey who have helped me understand it. The knowledge and understanding of the survey was the integral part in conceptualization of the project. Furthermore, I would also like to extend my sincere gratitude towards Mr. Sumit Maskey, Mr. Shamir Kumar Singh and Ms. Priyanka Singh for their expert guidance in structure and civil engineering matters. I am utterly thankful towards the NSET organization for providing me with the data essential to this project for research purposes. I acknowledge the efforts of the entire UNIGIS Kathmandu team as well, especially Dr. R. A. Mandal for being ever willing to extend a helping hand to his students. I would also like to thank my family, especially, Mrs. Smita Dahal, Ms. Shweta Khanal and Dr. Ichchha Neupane for providing me much needed support during all of my studies. Last but not the least, I thank my friends who have always provided me with the moral support and inspiration to accomplish my tasks. Nishanta Khanal November, 2017 iii Abstract Buildings are very important for people to live but when earthquake strikes many buildings can become very dangerous to people’s lives. As Nepal is known to experience earthquakes periodically, the buildings need to be assessed so that proper action can be taken place to create an earthquake resilient environment. This study was conducted to apply GIS in order to analyze the earthquake vulnerability of buildings by considering multiple criteria of building structure and also to study the spatial distribution of buildings that are most likely to cause damage. The study region chosen for this research was Birendranagar Municipality (wards 5,6,7,8,9,10,16,17 and 18), Birtamod and Vyas. The study focused on data from Building Inventory Data Survey (BIDS), a mobile based survey run by National Society for Earthquake Technology (NSET), to conduct the analysis. A Web-GIS application for validating the BIDS datasets was also developed. In order to assess the buildings, first the earthquake hazard in the three study regions were identified. Then the factors of buildings that contribute to the earthquake vulnerability were identified. Then, pairwise comparison method was used to find the factors’ weights which was used to compute Earthquake Vulnerability Index (EVI) of those buildings. This was used to compute the probability of damage to the buildings. Highly damage prone building’s collapse zone was also assessed to identify safe buildings and people that could be damaged due to nearby vulnerable buildings. The result of this research shows that in all three study areas, there are less than 10% buildings that are built as well as they can be when it comes to building structure. The results also showed that EVI was similar among the three municipalities showing that there are similar construction practices in the three study regions. Furthermore, there were a lot of buildings with high collapse probability in Birendranagar and Vyas. Because of lower iv earthquake hazard in Birtamod, even though the buildings had similar EVI, the buildings were found to be safer comparatively. The results suggest that there is the need to spread awareness among various stakeholders such as house owners and masons. Various skill oriented training programs could be beneficial as well. Given the sheer number of buildings that are highly damage prone, governing bodies also should consider some sort of action plan to make these stronger. This is made possible as this study has identified and located highly vulnerable buildings. v Table of contents Science pledge ................................................................................................................ ii Acknowledgements ....................................................................................................... iii Abstract .......................................................................................................................... iv Table of contents ........................................................................................................... vi List of figures .................................................................................................................. x List of tables ................................................................................................................... xi List of maps................................................................................................................... xii List of abbreviations .....................................................................................................xiii Chapter-1: Introduction .................................................................................................. 1 1.1 Background ........................................................................................................ 1 1.1.1 Building Inventory Data Survey (BIDS) ........................................................ 3 1.1.2 Need assessment ........................................................................................ 4 1.1.3 Research approach ..................................................................................... 5 1.2 Objectives of the project ..................................................................................... 6 1.3 Introduction of the study area.............................................................................. 7 1.3.1 Birendranagar municipality .......................................................................... 8 1.3.2 Birtamod municipality ................................................................................... 8 1.3.3 Vyas municipality ......................................................................................... 8 1.4 Literature Review .............................................................................................. 12 1.4.1 Seismic hazard in Nepal ............................................................................ 12 1.4.2 The Modified Mercalli Intensity (MMI) Scale............................................... 13 vi 1.4.3 Earthquake vulnerability assessment of buildings ...................................... 14 1.4.4 Factors affecting seismic vulnerability assessment of buildings ................. 15 1.4.5 Collapse zone ............................................................................................ 20 1.5 Assumptions ..................................................................................................... 21 Chapter-2: Methodology ............................................................................................... 22 2.1 Building Inventory Data Survey (BIDS) data collection ...................................... 23 2.1.1 Pre-Survey ................................................................................................ 23 2.1.2 Post-Survey ............................................................................................... 25 2.2 Data validation using Web-GIS application ....................................................... 25 2.2.1 Web-GIS application development ............................................................. 26 2.2.2 Data validation and correction ................................................................... 29 2.3 Software used ................................................................................................... 30 2.4 GIS data collection and data preparation .......................................................... 31 2.4.1 Data collection ........................................................................................... 31 2.4.2 Data preparation ........................................................................................ 35 2.5 Identifying seismic hazard in target municipalities ............................................. 36 2.6 Identifying building vulnerability factors ............................................................. 38 2.7 Assigning weight to factors using pairwise comparison method ........................ 41 2.8 Calculating earthquake vulnerability indices of every building ........................... 46 2.9 Calculating probability of damage ..................................................................... 47 2.10 Buffer analysis .................................................................................................