CCiittyy UUnniivveerrssiittyy ooff NNeeww YYoorrkk ((CCUUNNYY)) CCUUNNYY AAccaaddeemmiicc WWoorrkkss Dissertations, Theses, and Capstone Projects CUNY Graduate Center 2-2018 EEvviiddeennccee ooff tthhee 11776622 AArraakkaann aanndd PPrriioorr EEaarrtthhqquuaakkeess iinn tthhee NNoorrtthheerrnn SSuunnddaa SSuubbdduuccttiioonn Dhiman Ranjan Mondal The Graduate Center, City University of New York How does access to this work benefit you? Let us know! More information about this work at: https://academicworks.cuny.edu/gc_etds/2545 Discover additional works at: https://academicworks.cuny.edu This work is made publicly available by the City University of New York (CUNY). Contact: [email protected] EVIDENCE OF THE 1762 ARAKAN AND PRIOR EARTHQUAKES IN THE NORTHERN SUNDA SUBDUCTION by Dhiman Ranjan Mondal A dissertation submitted to the Graduate Faculty in Earth and Environmental Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy, The City University of New York 2018 Copyright © 2018 Dhiman Ranjan Mondal All Rights Reserved II Evidence of the 1762 Arakan and prior earthquakes in the Northern Sunda Subduction By Dhiman Ranjan Mondal This manuscript has been read and accepted for the Graduate Faculty in Earth and Environmental Sciences in satisfaction of the dissertation requirements for the degree of Doctor of Philosophy. Professor Dr. Cecilia McHugh Date: ______________________ ______________________________ Chair of the Examining Committee Professor Dr. Cindi Katz Date: ______________________ ______________________________ Executive Officer Supervisory Committee Dr. Harold Connolly Dr. Jeffrey Marsh Dr. Michael Steckler Dr. Richard Mortlock THE CITY UNIVERSITY OF NEW YORK III Abstract Evidence of the 1762 Arakan and Prior Earthquakes in the Northern Sunda Subduction By Dhiman Ranjan Mondal Advisor: Professor Dr. Cecilia M. McHugh The objective of this dissertation is to understand the seismic hazard associated with Arakan segment of the northern Sunda subduction along SE Bangladesh. In order to do that, it is necessary to document geologic evidence for the 1762 Arakan earthquake and prior events, to help estimate the recurrence interval (repeat time) for that earthquake. Historical records described that the 1762 earthquake caused extensive damage along the Arakan segment of the Sunda subduction system. But the geologic evidence for the earthquake farther north is necessary to better understand its associated seismic hazard to the densely populated nation of Bangladesh. This dissertation presents the results obtained from U/Th dating of the dead and live coral microatolls including their elevations measured by high precision GPS from the Saint Martin’s Island, DEM analysis and elevation of terraces from Teknaf coast and fault dislocation modeling based on the data obtained from the Saint Martin’s Island and Teknaf. Coral microatolls from Saint Martin’s island documents the evidence of the 1762 and prior earthquakes. The U/Th ages documents strong evidence of microatoll die offs related to the 1762 earthquake. The >2 m elevation difference between the dead microatolls and present-day living corals suggest that the microatolls died due to the coseismic uplift of 1762 Arakan earthquake. This dissertation also provides evidence for two additional earthquakes taking place in ~700 and ~1140 C.E. which suggests an earthquake recurrence interval of ~500 years. IV Geomorphic studies documented three terraces along the coast of Teknaf. Several marine terraces have been previously documented along the west coast of Myanmar. The youngest of these terraces has been correlated to the coseismic uplift of 1762 Arakan along the Myanmar coast. The terraces along the coast of Teknaf are characterized by flat to semi-flat surfaces followed by sharp topographic rises. DEM (Digital Elevation System) analysis and GPS (Global Positioning System) survey documented 2 to 3 terraces. Among these three, the youngest terrace is possibly linked to the 1762 Arakan Earthquake but the ages have not been verified. Modeling using the data obtained from Saint Martin’s Island, Teknaf and other published articles (for the west coast of Teknaf) suggest a fault dipping at 10-15° to the northeast. The result of coseismic slip inversion shows 15 - 25 m of reverse slip along the Arakan rupture segment, which was accommodated by the upper plate failure. Based on our results from coral microatolls, terraces and the modeling study, this dissertation suggests that this segment of the Arakan collision zone has the potential to cause a future earthquake of Mw>8 which can produce a devastating effect to the inhabitants of Bangladesh, Myanmar and Eastern India. V This dissertation is dedicated to my aunt Bharati Rani VI Acknowledgements This dissertation concludes 5 ½ years of my graduate study and research at the City University of New York. I would like to take this opportunity to express my heartfelt gratitude to all the people who have helped me get to this point. First and foremost, I would like to express my deep and sincere thanks to my dissertation advisor Professor Cecilia McHugh. This research work and dissertation would not have been possible without her guidance, support and mentorship. Over the past years, countless meetings and countless hours of discussion helped me to enrich my knowledge in both field and laboratories. I also would like to thank my other committee members, Dr. Michael Steckler, Dr. Richard Mortlock, Dr. Harold Connolly and Dr. Jeffrey Marsh for taking their time out of their busy schedule to review this work. Special thanks to the Earth and Environmental Sciences department at Queens College for providing me the lab and office facility. This is the place where I spent most of my last 5 years with joy and happiness. Also, thanks to my labmates- Md. Sharif Mustaque, Edwice Lature, Amanda Bastas-Hernandez, and Pariskeh Hosseini. Special thanks to the Fairbank Laboratory of Rutgers University for letting me use the clean lab facility and ICPMS. I would like to express my gratitude to Dr. Richard Mortlock and Dr. Nicole Adbul for providing me training on chemical analysis of coral. I would like to show my gratitude to Queens College, Gural Foundation, Graduate Center Dissertation Fellowship, Office of Naval Research and National Science Foundation for providing me the financial support to complete this dissertation, and Dr. Peter Knappett for providing me his GPS which was a key instrument in this research. VII Department of Geology at the University of Dhaka provided unconditional support during the fieldworks in Saint Martin’s Island and Teknaf. Special thanks to my former M.Sc. advisor Dr. Syed Humayun Akhter for the support that he provided during the fieldwork in Bangladesh. Graduate student Pritam Saha, Masud Iqbal, Alamgir Hossain, Mohibul Hossain, Enayet Shovon provided unprecedented support as field assistant. Finally, I would especially thank my family. My lovely wife, Dr. Mousumi Joysoual has been extremely supportive of me throughout this entire process and has made countless sacrifices to help me get to this point. My daughter Arunima Joyoshree has continually provided the requisite breaks from the thesis, and the motivation to finish my degree with expediency. My father Amulya Ranjan Mondal, mother Joyanti Rani Mondal, my younger brother Amit Ranjan Mondal, my father-in-law Moti Prasad Joysoual, mother-in-law Munni Saha and sister-in-law Mita Joysoual deserve special thanks for their continued support and encouragement. Without such a team behind me, I doubt that I would be in this place today. VIII Abbreviations BIWTA Bangladesh Inland Water Transport Authority DDW Double De-ionized Water DEM Digital Elevation Model EGM96 Earth Gravitational Model 1996 ENSO El Nino Southern Oscillation GEM Global Earthquake Model GPS Global Positioning System GT Gigaton HLS Highest Level of Survival ICPMS Inductively Coupled Plasma Mass Spectrometry IODM Indian Ocean Dipole Moment MMI Modified Mercalli Intensity RPD Retarding Potential Quadruple RTX Real Time eXtended SD Standard Deviation SEM Secondary Electron Multiplier SRTM Shuttle Radar Topographic Mission SSB Sample Standard Bracketing USGS United States Geological Survey XRD X-Ray Diffraction IX