Thursday, 02 February 2017 14:21

The Italy 18 January 2017 earthquakes captured by the Sentinel-1 and ALOS-2 satellite radar data

Despite the copious snow cover and the adverse weather conditions, the Sentinel-1 and ALOS-2 satellites allowed a team of IREA-CNR scientists to retrieve the Earth’s surface deformation induced by the recent seismic sequence in central Italy, whose main shock reached a magnitude of Mw 5.5 on 18 January 2017.

Thanks to the joint processing of two radar images acquired across the main event by the Sentinel-1 satellite constellation of the European Copernicus program, it was possible to generate the so-called co-seismic Interferogram (see Figure 1a), a map that permits scientists to directly relate the radar signal to the displacement of the ground.

Exploiting the ALOS-2 data of the Japanese Space Agency (JAXA), it has also been carried out a similar analysis that confirms the main findings obtained via the Sentinel-1 data (see Figure 1b).

Starting from the shown interferograms, the corresponding displacement maps have also been generated. They show (see Figures 1c and 1d) that the Earth surface moved away from the satellite with a maximum of about 10 cm in an area south to Amatrice. A zoom of the area affected by the coseismic deformation (displayed in red) is shown in figure 2.

These maps have been subsequently provided to INGV for modeling the causative source of the seismic event.

A more detailed analysis is provided here:

The activity is coordinated by the Italian Department of Civil Protection (DPC) and is performed by a research team of the Institute for Electromagnetic Sensing of the Environment of the National Research Council (CNR-IREA in Naples) and the National Institute of Geophysics and Volcanology (INGV), which are centers of competence in the satellite data processing and seismology sectors, respectively, with the support of the Italian Space Agency (ASI). The Copernicus program is led by the European Commission. The European Space Agency is in charge of developing the Sentinel satellites; ESA also operates the two Sentinel-1 satellites. The ALOS-2 data were provided by JAXA in the framework of an agreement with the Italian Space Agency (ASI) for the exchange of data useful to emergency management.

The activity has been also supported by the GEP project of the European Space Agency (ESA) and the project "High Technological Infrastructure for Integrated Monitoring of Climate and Environment" (I-AMICA) funded by the Italian Ministry of Education, University, and Research as part of the National Operational Programme (PON).     

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Figure 2 - Zoom of the area affected by the co-seismic deformations obtained from the Sentinel-1 map of Figure 1c.

To view the image in Google Earth click here 


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Figure 1 – Co-seismic interferograms and displacement maps generated from Sentinel-1 and ALOS-2 data. a) Sentinel-1 interferogram relevant to the 12012017-24012017 ascending pair (Track 117). b) ALOS-2 interferogram relevant to the 02112016-25012017 ascending pair (Track 197). c) Displacement map (in LOS) computed from the Sentinel-1 interferogram of Figure 1a. d) Displacement map (in LOS) computed from the ALSO-2 interferogram of Figure 1b. Black star indicates the location of the Mw 5.5 epicenter of the 18 January 2017. Black lines indicate main regional structures. Contains modified Copernicus data (2017) and ALSO-2 data (©JAXA 2016-2017).









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