Tehran Ground Subsidence is a slow and silent Ticking Bomb.
Power outages, gas pipe bursting, rails deformed, sinkholes, buildings tilting, roads cracking...
Tehran plains ground subsidence has been covered and studied in recent decades however this man-induced phenomenon is now catching Tehran city itself for the last years thus endangering a growing population of 13 million inhabitants and its critical infrastructures.
Excessive groundwater extraction has caused land subsidence at a rate of up to 25 centimeters per year in some areas.
In this brief study, Differential InSAR processing was used to identify and estimate land displacement by using Sentinel-1A SAR SLC imageries. Our dataset includes 14 pairs of images from January 2020 to May 2021 with a small temporal-perpendicular baseline and using the SBAS approach, processing was performed by the GAMMA Software via ASF DAAC .
The results were further converted to an estimated vertical ground displacement map with a maximum average subsidence rate of 40mm/year.
It is known that subsidence phenomenons are non-linear, this estimated average rate takes into account events that occurred with higher subsidence during the period of images acquisition as well as events with ground uplift.