Reliability assessment of land subsidence monitoring results using PSI technique in Ho Chi Minh City, Vietnam

ABSTRACT

Groundwater exploitation, soft ground, and urban development are the main causes of land subsidence in Vietnam. This study focuses on identifying, zoning, monitoring, and evaluating land subsidence using PSI technique with IBI method applied to Ho Chi Minh City. The results show diverse land subsidence trends from 2014 to 2021 with different levels in varying locations 98,278 km² had subsided by over 10 cm, 214,593 km² had subsided by 5 to 10 cm, and 1.377,897 km² had subsided by less than 5 cm. Notably, certain areas have higher subsidence funnel centres. To ensure accuracy when using PSI techniques, both natural and human-induced factors must be considered during data collection, which influences the actual subsidence rate. Though difficult, this technique provides reliable insights into this complex phenomenon, e.g. in the geodetic precise levelling method to detect millimetre-level deformations in urban areas. The average PS density in urban areas is between 0,5% and 2,5% of the original number of pixels. The positioning accuracy of a PS is within 1 m in all three directions if a large number of SAR scenes are used. Therefore, the results have been documented with 1 mm precision.

KEYWORDS:

• Subsidence
• remote sensing
• PSI, Sentinel-1
• time-series

Acknowledgments

Many thanks must go to Dr. Le Quoc Hung and our colleagues, the research group of the National Remote Sensing Station, who have generously given their time, materials, suggestions, and assistance throughout.

Disclosure statement

No potential conflict of interest was reported by the author(s).