Rapid response to the M_w 4.9 earthquake of November 11, 2019 in Le Teil, Lower Rhône Valley, France

On November 11, 2019, a Mw 4.9 earthquake hit the region close to Montelimar (lower Rhône Valley, France), on the eastern margin of the Massif Central close to the external part of the Alps. Occuring in a moderate seismicity area, this earthquake is remarkable for its very shallow focal depth (between 1 and 3 km), its magnitude, and the moderate to large damages it produced in several villages. InSAR interferograms indicated a shallow rupture about 4 km long reaching the surface and the reactivation of the ancient NE-SW La Rouviere normal fault in reverse faulting in agreement with the present-day E-W compressional tectonics. The peculiarity of this earthquake together with a poor coverage of the epicentral region by permanent seismological and geodetic stations triggered the mobilisation of the French post-seismic unit and the broad French scientific community from various institutions, with the deployment of geophysical instruments (seismological and geodesic stations), geological field surveys, and field evaluation of the intensity of the earthquake. Within 7 days after the mainshock, 47 seismological stations were deployed in the epicentral area to improve the Le Teil aftershocks locations relative to the French permanent seismological network (RESIF), monitor the temporal and spatial evolution of microearthquakes close to the fault plane and temporal evolution of the seismic response of 3 damaged historical buildings, and to study suspected site effects and their influence in the distribution of seismic damage. This seismological dataset, completed by data owned by different institutions, was integrated in a homogeneous archive and distributed through FDSN web services by the RESIF data center. This dataset, together with observations of surface rupture evidences, geologic, geodetic and satellite data, will help to unravel the causes and rupture mechanism of this earthquake, and contribute to account in seismic hazard assessment for earthquakes along the major regional Cévenne fault system in a context of present-day compressional tectonics

ESA SNAP – Stamps integrated processing for sentinel-1 persistent scatterer interferometry

International audienc

Calculation of actual motion components in vector domain for Persistent Scatterers

International audienceThe combination of ascending and descending Persistent Scatterers Interferometric (PSI) data by means of resampling and/or spatial interpolation, separately for each Synthetic Aperture Radar (SAR) geometry, is a commonly followed procedure, limited though by the reduced spatial coverage and the introduced uncertainties from multiple rasterisation steps. Herein, an alternative approach is proposed for combining different PSI line-of-sight (LOS) observables in the vector domain, based on the geographic proximity of PS point targets. An alternative procedure is presented herein, using PS data in their initial vector format and by exploiting vector manipulation capabilities as well as the geostatistical modules already available in many GIS software packages. In the proposed post-processing scheme all necessary analysis steps are performed by means of attributes transfer and calculations between features geodatabases, prior to any rasterisation. By increasing the number of input point vectors during subsequent interpolation, the overall error budget coming from spatial interpolation is being reduced. The increase of output surface resolution together with the reduction of interpolation error budget for the combined PSI results is of significant importance during modelling of ground motion or integration of PSI measurements with GNSS observations. The benefit of working with vector data, instead of raster layers, especially in saving storage space should be more pronounced when large stacks of PSI or wide area processing results are involved. The proposed approach are applicable to any PSI dataset independently of the processing scheme. The advantages of the proposed vector-based approach compared to the commonly used grid-based procedure is being demonstrated using real data

Amatrice Earthquake - Sentinel-1 TOPS Ascending - Differential Interferogram (S1A_20160815-S1A_20160827)

Differential S1 TOPS interferogram (S1A_20160815-S1A_20160827) from ascending orbit 117. A Sentinel-1 TOPS co-seismic interferogram of the Amatrice earthquake in Italy on the 24th of August 2016. Processing was performed with the ESA SNAP toolbox (http://step.esa.int/) including TOPS InSAR processing, removal of topographic phase, phase filtering and orthorectification. S1A data were downloaded from the Sentinel-1 Scientific Data Hub. Contains modified Copernicus data (2016

Vector-based approach for combining ascending and descending persistent scatterers interferometric point measurements

<p>The combination of ascending and descending persistent scatterers interferometric (PSI) data by means of resampling and/or spatial interpolation, separately for each synthetic aperture radar geometry, is a commonly followed procedure, limited though by the reduced spatial coverage and the introduced uncertainties from multiple rasterization steps. Herein, an alternative approach is proposed for combining different PSI line-of-sight observables in the vector domain, based on the geographic proximity of PS point targets. In the proposed nearest neighbour vector approach all necessary analysis steps are performed by means of attributes transfer and calculations between features geodatabases, prior to any rasterization. By increasing the number of input point vectors during subsequent interpolation, the overall error budget coming from spatial interpolation is being reduced. The advantages of the proposed vector-based approach compared to the commonly used grid-based procedure are being demonstrated using real data.</p

Amatrice Earthquake - Sentinel-1 TOPS - E-W Motion

E-W motion component of the Amatrice earthquake from Sentinel-1. A Sentinel-1 TOPS co-seismic interferogram of the Amatrice earthquake in Italy on the 24th of August 2016. Processing was performed with the ESA SNAP toolbox (http://step.esa.int/). S1A data were downloaded from the Sentinel-1 Scientific Data Hub. Contains modified Copernicus data (2016

Vector-based approach for combining ascending and descending persistent scatterers interferometric point measurements

The combination of ascending and descending persistent scatterers interferometric (PSI) data by means of resampling and/or spatial interpolation, separately for each synthetic aperture radar geometry, is a commonly followed procedure, limited though by the reduced spatial coverage and the introduced uncertainties from multiple rasterization steps. Herein, an alternative approach is proposed for combining different PSI line-of-sight observables in the vector domain, based on the geographic proximity of PS point targets. In the proposed nearest neighbour vector approach all necessary analysis steps are performed by means of attributes transfer and calculations between features geodatabases, prior to any rasterization. By increasing the number of input point vectors during subsequent interpolation, the overall error budget coming from spatial interpolation is being reduced. The advantages of the proposed vector-based approach compared to the commonly used grid-based procedure are being demonstrated using real data