Geological Remote Sensing Group – GRSG

When the GRSG 30th Conference takes place in Frascati this December, ESA staff will take the opportunity to provide attendees with two insightful lectures covering how the Sentinel programme can support their work.

These lectures are planned to take place during the lunch breaks on the first two days.

Day-1: Use of EO for Geology
Earth Observation can be a major source of information for new and improved geological, mineral, regolyth, geomorphological and structural mapping.

Data provided by Landsat-8, archived data from Hyperion, ASTER, SRTM, ERS or ENVISAT as well as data from ESA Earth Explorers and products from commercial satellites fused with geophysical and in-situ observations have offered geologists with a wide range of mapping opportunities.

The Sentinel family reinforces our capabilities to carry on geological studies and applications, with its large volumes of free and systematic observations acquired worldwide.

This short lecture will focus on the characteristics of various Sentinel satellites, explaining how various field of geology (such as geologic mapping, structural geology, geomorphology, geotectonics, geophysics, volcanology, engineering geology, environmental geology or natural hazard) may benefit from the usage of such data.

Day-2: Land Subsidence with Sentinel-1: an InSAR demo with Open Tools using RUS Service
Land subsidence monitoring is very important for urban and agricultural areas which are susceptible to ground instabilities for both local and regional scale.

The reasons for this phenomenon can be related to either anthropogenic activities (e.g. excess groundwater pumping, subterranean mining processes, rapid urbanisation) or natural-geological ones (e.g. hydrocompaction in low density soils, liquefaction, crustal deformation).

In this demonstration ESA will use the SAR interferometry (InSAR) technique to identify and map land subsidence over Mexico City.

InSAR is an effective method that allows monitoring of ground displacement over large areas, giving insight into the spatial distribution of the subsidence rates. Land subsidence in Mexico City, which is caused by groundwater over-exploitation, is estimated to be more than 9 meters over the last century, resulting in damages to buildings, streets, sidewalks, sewers, storm water drains and other infrastructure. Previous studies of InSAR using ERS data, showed a maximum subsidence rate larger than 30 cm/year in some parts of the city.

Since the city is partially built on the area of a former lake (Lago Texcoco) and it rests on the heavily saturated clay, it is collapsing due to the over-extraction of groundwater. Current subsidence rates using Sentinel-1 SAR data are around 2.5 cm/month.

Presenters will be using the ESA SNAP Sentinel-1 Toolbox, within the free RUS environment, as all Open Source Tools and Software needed (ESA SNAP, QGIS) are already available and pre-installed in the RUS VMs.