Surface deformation evolution in the Pearl River Delta between 2006 and 2011 derived from the ALOS1/PALSAR images

Genger Li,Qi Liu,Zhiqiang Xiong,Yanan Du,Shuran Luo,Guangcai Feng,Xiaoling Zhu,Rongan Xie

doi:10.1186/s40623-020-01310-2

Genger Li, Qi Liu + Show 6 more

Open Access

https://doi.org/10.1186/s40623-020-01310-2

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Abstract

This study monitors the land subsidence of the whole Pearl River Delta (PRD) (area: ~ 40,000 km2) in China using the ALOS1/PALSAR data (2006–2011) through the SBAS-InSAR method. We also analyze the relationship between the subsidence and the coastline change, river distribution, geological structure as well as the local terrain. The results show that (1) the land subsidence with the average velocity of 50 mm/year occurred in the low elevation area in the front part of the delta and the coastal area, and the area of the regions subsiding faster than 30 mm/year between 2006 and 2011 is larger than 122 km2; (2) the subsidence order and area estimated in this study are both much larger than that measured in previous studies; (3) the areas along rivers suffered from surface subsidence, due to the thick soft soil layer and frequent human interference; (4) the geological evolution is the intrinsic factor of the surface subsidence in the PRD, but human interference (reclamation, ground water extraction and urban construction) extends the subsiding area and increases the subsiding rate.

Highlights

Deltas have abundant natural resources, superior natural environment and geographical locations, so they accommodate the most intensive human activities
The interferometric synthetic aperture radar (InSAR) technique has been widely used for monitoring surface subsidence in delta areas, including the Pearl River Delta (PRD), because of its wide spatial and long temporal coverage (Higgins et al 2014)
Area1 is stable but Area2 has obvious subsidence, so Discussion Surface deformation in the PRD is usually caused by the joint force of natural geological evolution and human activities

Summary

Introduction

Deltas have abundant natural resources, superior natural environment and geographical locations, so they accommodate the most intensive human activities. About 24 of the 33 major deltas in the world have surface subsidence, including the Pearl River Delta (PRD) in China (Syvitski et al 2009). As one of the most economically developed and urbanized areas in China, the Pearl River Delta (PRD) has the largest urban agglomeration in the world and the population of 55 million Ma et al (2019) investigated the subsidence of the Guangdong–Hong Kong–Macao Greater Bay Area and found that the overall subsidence ranged from 0 to 112.3 mm/year, according to the 2015–2017 Sentinel-1 images.

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Discussion

Conclusion