InSAR reveals coastal subsidence in the Pearl River Delta, China

Abstract

SUMMARY The Pearl River Delta (PRD) is one of the most important economic regions with the highest population densities in China. With its dramatic increasing population and economy, hazards associated with land subsidence frequently occur here that amplify the negative effect of sea level rise. However, land subsidence has not been regularly measured in this region. Here, we use interferometric synthetic aperture radar (InSAR) to investigate the rate and extent of land subsidence in the PRD region. Assuming purely vertical displacements, multi‐track interferograms from different viewing geometries are combined to estimate the linear rate map and time series at a higher resolution in time than is possible with a single track. The results show apparent subsidence along the coastal region of Shenzhen associated with rapid urban development in recent years. The average subsidence rate within 500 m of the coast is about 2.5 mm yr−1, and the maximum is up to about 6 mm yr−1 with respect to the central part of the city. Much of the land surface in the PRD is less than 2 m above mean sea level; high‐precision geodetic measurements throughout the PRD region are therefore critical for conducting risk assessments, considering the rate of about 2–3 mm yr−1 of current global sea level rise.

Coastal Subsidence Monitoring Associated with Land Reclamation Using the Point Target Based SBAS-InSAR Method: A Case Study of Shenzhen, China

“…In Shenzhen coastal zone, the subsidence of the reclaimed land and sediment layer dominates the ground deformation. Hence, the deformation in our study area was assumed mainly in the vertical direction and the LOS displacement was directly back-projected into the vertical direction using the local incidence angle [36].…”

Does the lava lake of Erta ‘Ale volcano respond to regional magmatic and tectonic events? An investigation using Earth Observation data

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Ground deformation mapping by fusion of multi-temporal interferometric synthetic aperture radar images: a review

“…Instead of calculating the coherence of all pixels, a very small portion of pixels sampled, say, by intensity variation can be used to reduce the computation burden. For the multiple-master stack, we can use the minimum spanning tree (MST) to select interferograms that can maximise the total coherence (Refice et al 2006, Wang et al 2012. As an example, Figure 4 shows the MST generated from a stack of TerraSAR-X interferograms over Hong Kong according to the sampled coherence.…”