PhD Oral Defense of Pham Tien Dat: Statistical analyses for coastal hazard datasets: case studies of washer sedimentation from storms and tsunamis, and sea-level records from tide gauges
- Oral Defense
About the Event:
Coastal hazard assessments commonly require the integration of different data sets that, in turn, require appropriate statistical techniques to reveal underlying processes. Here, I present three studies in which I apply and develop different statistical methods for a broad sedimentological data set and sea-level time series. In the first study, I use a series of statistical analyses to examine the use of grain size parameters, mineral composition and trace element geochemistry in determining the provenance of tsunami (the 2004 Indian Ocean Tsunami (IOT) and three paleo-tsunami) deposits and the 2007 storm surge deposit on Phra Thong Island, Thailand. I also evaluate whether the 2004 IOT tsunami and 2007 storm deposits could be discriminated using grain size and geochemistry. The key findings are that the geochemistry data are statistically inadequate to distinguish the provenance of the modern storm and tsunami deposits, but the mean grain size can potentially be a better discriminator. In addition, the sediment sources of each of overwash deposits are diverse. In the second study, I investigate interannual sea-level variations by using sea-level records at ten tide gauges (TGs) around the South China Sea (SCS). The results reveal that the El-Nino Southern Oscillation (ENSO) significantly contributes to interannual sea-level signals but that its influences vary across the study area, whereas the winter monsoon clearly impacts the sea level in the northern SCS. In the third study, I examine spatio-temporal variation of extreme sea level (ESL) around the SCS. The results reveal contrasting mechanisms for generating surges in the northern and southern SCS; and that the changes in ESL are broadly consistent with the changes in mean sea level. I also calculate the temporal variability of the return levels and show they are significantly correlated with climatic variability in the region.
Chair of the Oral defense
- Associate Professor Federico Lauro (Chair), Asian School of the Environment, Singapore
Members of the Examination Committee:
- Professor Andrew Cooper (External Examiner), Geography and Environmental Sciences, Ulster University, Ireland
- Professor Ray Weldon (External Examiner), Department of Geological Sciences, University of Oregon, USA
- Associate Professor Nathalie Goodkin (Internal Examiner), Earth Observatory of Singapore and Asian School of the Environment, Singapore
- Associate Professor Adam Switzer, Earth Observatory of Singapore and Asian School of the Environment, Singapore
- Assistant Professor Emma Hill, Earth Observatory of Singapore and Asian School of the Environment, Singapore
About the Speaker:
Pham Tien Dat is a PhD candidate at the Asian School of the Environment (ASE) – NTU. He received his Bachelor’s and Master’s degrees in Oceanography from Vietnam National University – Hanoi. Thereafter, he worked as a Government Officer in Vietnam Administration Seas and Islands, before moving to Vietnam Institute of Meteorology, Hydrology and Climate Change (Hanoi, Vietnam). In August 2011, he enrolled in the PhD program at ASE under the supervision of Associate Professor Adam Switzer. During his PhD, he has focused on using various statistical techniques to study different data sets from coastal hazard-related processes including tsunamis, storms and inter-annual sea-level change.