Authors
Marc C. Naeije1, Wim J. F. Simons1,*, Siriporn Pradit2,*, Sommart Niemnil3,4, Nalinee Thongtham 5, Mohamad A. Mustafar1,6 and Prakrit Noppradit2
1 Department of Space Engineering, Faculty of Aerospace Engineering, Delft University of Technology (TUDelft), 2622 HS Delft, The Netherlands; m.c.naeije@tudelft.nl (M.C.N.); mohamadasrul@uitm.edu.my (M.A.M.)
2 Coastal Oceanography and Climate Change Research Center, Marine and Coastal Resources Institution (MACORIN), Prince of Songkla University, 90110 Songkla, Thailand; prakrit.n@psu.ac.th
3 Royal Thai Naval Academy (RTNA), 10270 Samut Prakan, Thailand; sniemnil@gmail.com
4 Faculty of Science and Health Technology, Navamindradhiraj University, 10300 Bangkok, Thailand
5 Marine Ecologist Consultant for the Department of Marine and Coastal Resources (DMCR),
6 Centre of Studies for Surveying and Geomatics, Universiti Teknologi MARA Cawangan Perlis, 02600 Arau, Malaysia
* Correspondence: w.j.f.simons@tudelft.nl (W.J.F.S.); siriporn.pra@psu.ac.th (S.P.) 10210 Bangkok, Thailand; nalineeth@hotmail.com
Abstract
Temporal changes in vertical land motion (VLM) in and around Phuket Island in southern Thailand following the great 2004 Sumatra–Andaman megathrust earthquake have im-pacted the relative sea-level change estimates based on tide-gauge (TG) records. To better monitor the VLM, two new continuous global navigation satellite system (GNSS) stations have been installed in the past 5 years, situated on bedrock both near and at the Koh Taphao Noi Island TG in Phuket, which together with older global positioning system (GPS) data provides a clear in-sight in the VLM of Phuket Island from 1994 onward. In addition, satellite altimetry (SALT) data has been analyzed since 1992. The VLM (GPS) position and relative (TG) and absolute (SALT) sea-level change time series were successfully combined in pairs to validate each independent result (e.g., SALT − GNSS = TG): prior to the 2004 earthquake, the relative sea-level rise in Phuket was 1.0 ± 0.7 mm/yr, lower by 2.4 ± 0.2 mm/yr than the absolute sea-level rise caused by VLM. After the earthquake, nonlinear post-seismic subsidence has caused the VLM to drop by 10 cm in the past 17 years, resulting, by the end of 2020, in a relative sea-level rise by up to 16 cm. During the same period, other TG stations in south Thailand recorded similar sea-level increases. Combination with SALT further suggests that, prior to 2005, uplift (5.3 ± 1.4 mm/yr) of the coastal region of Ranong (north of Phuket) resulted in a relative sea-level fall, but since then, post-seismic-induced negative VLM may have significantly increased coastal erosion along the entire Andaman Sea coastline.
The data that supports the findings in the publication are attached as files in this repository. These are the raw RINEX files for the GNSS data, and the monthly-averaged tide gauge data. Satellite altimetry data is available through the RADS system.
Data files:
The GNSSDataThailand file contains the GNSS data (raw rinex files) from the TUDelft GPS stations PMBC, KTPH and SPKN in Thailand.
The TideGaugeDataThailand file contains the tide gauge data (montly averaged) for Phuket and the other five stations.
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