PSI and GNSS derived ground subsidence detection in the UNESCO Heritage City of Ahmedabad, Western India

Abstract

Presently, ground subsidence in urban areas is becoming a peril to the infrastructure and society. In this study, we conducted a detailed analysis of the results, based on the Persistent Scatterer Interferometry (PSI), Global Navigation Satellite System (GNSS) and groundwater in the ‘World Heritage City’ of Ahmedabad, a major metro city in western India. The PSI technique is applied to measure the ground subsidence using the Sentinel 1 A dataset for the period 2017 to 2020. The results reveal a subsidence, maximum up to the level of 25 mm/yr in the areas of the southeast and west parts of the city. Analysis derived from GNSS results indicates a significant amount of ground subsidence based on the 2009–2020 dataset. Groundwater data (1995–2019) were analyzed to identify factors likely to cause ground subsidence and the results are in close agreement with the PSI and GNSS results.

Keywords:

• Persistent Scaterrer InSAR (PSI)
• GNSS
• groundwater
• subsidence
• Western India

Acknowledgements

We are grateful to the DG, ISR, Department of Science and Technology, Govt of Gujarat, for providing required support for the study. The authors are highly grateful to the team of developer, SNAP-stamps, for providing regular updates and help through the forum, especially to Andreas Braun, University of Tuebingen, Germany and Thorsten Hoeser, DLR-DFD, Germany. The groundwater level data is downloaded from www.cgwb.gov.in and GNSS-IGS data is downloaded from (http://itrf.ensg.ign). We are grateful to Mr. H. Gajjar (CHC Navigation India Pvt. Ltd) for providing raw GNSS data (2017 to 2020) of Ahmedabad city.

Disclosure statement

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

Data availability statement

In the present study we have used Sentinel 1 A dataset from 2017 to 2020, which is available at (https://sentinel.esa.int/; http://scihub.copernicus.eu) and detail of the dataset used is given in the Table S1. GNSS raw/supporting dataset from 2009 to 2020 used in the study and data is available from the corresponding author on request. Groundwater data used is downloaded from the site of Central Groundwater Board (CGWB) and available at www.cgwb.gov.in.