A Study of the Relationship Between Changes in Piezometric Pressure and Land Subsidence Rate from InSAR Time-Series Technique

Abstract

To monitor land subsidence in Nakhon Pathom and Samut Sakhon Province and to study the relationship between changes in piezometric pressure and land subsidence rate, this research applied InSAR time series analysis as a tool that provides adequate spatial data. Using Sentinel-1 data from June 2018 to October 2021, we have developed the processing procedure using SNAP for interferometric handling and data preparation for Persistent Scatterer of StaMPS and TRAIN application platform and time series plots processing. We found over 800,000 observations in the study area and the land subsidence rate of the ground ranged from - 33.13 to +32.79 mm. per year. From piezometric pressure data stations, such as Nakhon Pathom province station and Samut Sakhon province station, within a radius of 200 m, the land subsidence rate of the ground ranged from -4.81 to +0.27 mm. per year and -16.11 to -3.27 mm. per year, respectively. From piezometric pressure data from May 2018 to September 2021 in two locations, the trend of change in piezometric pressure declines rate ranged from 2.5 to 8.4 kPa. per year and 1.8 to 18.6 kPa. per year of the time frame of analysis. The variations between changes in groundwater pressure and land subsidence values from the InSAR technique were relatively consistent.