Towards unraveling total subsidence of a mega-delta – the potential of new PS InSAR data for the Mekong delta

Abstract. Total subsidence in deltaic areas is the cumulative effect of a range of driving mechanisms, both natural and anthropogenic. The populous and low-lying Vietnamese Mekong delta is facing accelerating subsidence rates and effective mitigation strategies are urgently needed to save-guard the future sustainability of the delta. This paper gathers results from existing measurements and estimates of subsidence in the Mekong delta and presents new, delta-wide datasets of PSI observations of vertical velocity from 2014–2019. We describe the practical application of this new data in ongoing projects in Vietnam and outline a planned approach to determine depth-dependent subsidence rates, using this new dataset in combination with field surveys and physics-based numerical models, to advance towards improved quantitation of the contributions of individual subsidence mechanisms.