Assessing changes in ground subsidence rates, Mekong Delta, Vietnam (2019-02-26)

<br/> Activation date: 2019-02-26 <br/> Event type: Other <br/> <br/> Activation reason: <br/> Time series plots are available under request&nbsp;per each&nbsp;persistent scatterer (PS) point&nbsp;(668710 PS points)&nbsp;indicating ground subsidence trend.Contact us at&nbsp;JRC-EMS-RISKRECOVERYMAPPING@ec.europa.eu.The EMSN062 service provides geospatial information supporting investigations into area based changes of subsidence rates and facilitating assessment of drivers of ground subsidence in the Mekong Delta, Vietnam. Primary objective of the service is provision of spatially and temporally consistent, dense and synoptic results giving insight on distribution and variance of subsidence phenomena in space and its dynamics in time. Persistent scatterers interferometry technique (PSI) and stacks of archive SAR imagery from Sentinel-1 sensor were used to measure displacements caused by ground subsidence and to estimate its average velocity in vertical direction.Average Ground Subsidence VelocityThe product shows patterns of estimated ground subsidence rate (i.e. its average velocity) in vertical direction for persistent scatterer points. The points and their displacement velocity in time were identified by PSI technique from stacks of Sentinel-1 images acquired within reference period November 2014 - January 2019.&nbsp;The result provide means to evaluate the ground subsidence patterns at various scales. Each PS point has an associated plot of displacement trend. Plots can be used to evaluate level of stability of temporal trend of ground subsidence for individual points: i.e. whether displacement rate is constant in time, has spatially related temporal patterns (fluctuations) or if accelerates in time.&nbsp;The product was not validated against ground data.&nbsp;&nbsp; <br/> <br/>