Activities in Italy
Anna Rita Pisani (ASI), Roberta Giuliani (DPC), Stefano Salvi (INGV), Daniela Di Bucci (DPC), Simona Zoffoli (ASI).
Satellite Earth Observation (EO) products, integrated with ground-based data, can effectively support seismic risk management activities. They contribute in particular to the hazard assessment, by providing important information on ground deformation rates, and to emergency response, by providing information needed to understand the phenomenon and to manage the response actions. This report aims at showing the contribution of EO-based scientific products, generated during the 2009 L'Aquila and 2012 Emilia earthquakes in Italy, to the emergency response managed by the Italian Department of Civil Protection (DPC), which is embedded within the Prime Minister’s Office and is the key coordinating body in case of national emergency.
Problem
In Italy, DPC coordinates the response of the National Service of Civil Protection to disasters (e.g., earthquakes, landslides, floods, volcanic eruptions, fires). DPC activities are supported by a number of national Centres of Competence (CC), which are research institutions and academies that integrate technological and scientific advancements in risk prediction (when possible) and prevention, risk mitigation and emergency response. Among the national CC there are also the Italian Space Agency (ASI) and the National Institute of Geophysics and Volcanology (INGV).
Currently, the DPC use of radar satellite data is in a pre-operational phase. Since 2009, during earthquake emergencies, procedures still not formally approved have been tested, and Earth Observation (EO) data contributions have been exploited providing useful results for DPC activities, in particular for event scenarios and situational awareness.
Satellite Earth Observation Data Application
In case of severe earthquakes in Italy, satellite products do contribute to the emergency response. For example geodetic GPS and InSAR imaging data (ERS, ENVISAT, ALOS, COSMO-SkyMed, TerraSAR X, Sentinel-1) are used to generate maps of ground deformation, caused by fault motion, measured in a very precise way (few millimeters) and at high resolution (pixel size up to few square meters). These maps are then employed to generate an accurate estimate of the earthquake source location and parameters, which are essential elements of the event scenario. Other useful information conveyed by the co-seismic ground deformation concerns the (re)activation of large landslides and deep-seated gravitational slope deformations, collapse of sinkholes, shallow caves or mines, passive mobilization of old fault planes, development of soil fractures, occurrence of soil liquefaction episodes. All these
Applications of Satellite Earth Observations 139 phenomena may imply an added hazard for the considered area, and their identification contributes to the situational awareness.
Further important information that can be extracted from the high resolution InSAR images concerns the diffuse effects of the seismic shaking on the built environment. The abrupt change of the surface properties caused, for instance, by building collapses can be detected, and its spatial extent precisely and rapidly mapped.
All these maps can be generated in near real time, being the images availability the limiting factor, since the processing, modeling, and interpretation phases require only few hours, while the first post- event images are generally obtained after 1-4 days.
Since 2009, in a joint effort including ASI, INGV and DPC, applications of satellite EO data during seismic emergencies have been carried out through specific projects.
The SIGRIS project (www.sigris.it), in particular, was mostly focused on exploiting the capacity of the COSMO-SkyMed constellation, a dual-use, 4-satellite X-band system devoted to civilian and defense uses, which is managed by ASI, and which guarantees the shortest possible global revisit time among all EO SAR satellites (down to 1 day for interferometric acquisitions). In this project the role of service providers was played by INGV, IREA-CNR (Institute for Electromagnetic Sensing of the Environment- National Research Council, that is as well a CC) and TRE (Tele-Rilevamento Europa, a spin-off company from the Politecnico di Milano University).
Among the outcomes of SIGRIS project, a first attempt to draw procedures on the activation of the CC that deal with satellite EO data was carried out. These pre-operational procedures were tested in the emergencies following the 2009 and 2012 earthquakes.
The activation of COSMO-SkyMed image acquisition for a seismic emergency in Italy takes place shortly after the occurrence of moderate to large magnitude earthquakes (> 5.0). The Council of Ministers, depending on the severity of the damages and consequences caused by the event, decides whether to declare the national state of emergency, which involves the entire National Service of Civil Protection under the DPC coordination. This prompts the CC activation for the generation, among the others, of EO-based science products. ASI turns COSMO-SkyMed in the state of highest priority, to monitor the crisis area with all available observational resources. Then the archive is examined, and a new acquisition plan is formulated to acquire post-event images matching the pre-event ones (a requirement for InSAR processing). The plan is devised and implemented by ASI, taking into account the requirements (geographic location and timing of acquisition) of the CC scientific teams. These teams process the images provided and generate added-value products: InSAR interferograms, maps of co-seismic ground displacement, maps of the general impact on the built environment, seismic source models, etc. These products are cross-validated by the CC and then provided to the DPC and the National Service of Civil Protection for their institutional use.
140 Applications of Satellite Earth Observations
Fig 1: Ground deformation map and earthquake source model generated for a magnitude 5.8 earthquake on May 29th, 2012 in the Emilia region in Northern Italy. The post-event image was acquired 5 days after the earthquake, and the source model was generated in 2 hours and validated using seismological and GPS data. These products can be used to define the event scenario.
Fig 2: Products generated for the April 6th 2009, Mw 6.3, L’Aquila earthquake (Central Italy). Left image: map of co-seismic ground displacement, where local environmental effects of earthquake are highlighted (reactivated fault scarps and slow moving landslides). Right image: detailed map of ground deformation triggered by the seismic shaking on a preexisting landslide. The first useful COSMO-SkyMed post-event image was acquired 6 days after the earthquake, the first version of the ground deformation map was generated in 4 hours later, and updated versions in the following days. The product here shown was generated several days after the earthquake, since field validation was deemed necessary.
Applications of Satellite Earth Observations 141 DPC takes benefits from the above-mentioned information in order to achieve a full understanding of the size of the seismic event occurred and, thus, to calibrate the emergency response in a more effective way. As an example, when planning the location of tent camps and provisional housing zones in the epicentral area, one has to take into special account the possibility of further displacements of landslides or the evolution of other geological instabilities that have already shown activation after an earthquake.
In a more general perspective, the National Service of Civil Protection indirectly benefits from the information coming from EO satellite data analysis as this contributes to the seismogenic source characterization, which is part of the scenario and seismic hazard assessment in the risk mitigation policies.
Value Chain
More Information
For more information, please feel free to contact: Anna Rita Pisani
Italian Space Agency [email protected] +39 06 8567 622 www.asi.it http://www.protezionecivile.gov.it www.ingv.it www.sigris.it
142 Applications of Satellite Earth Observations