Papers by Riccardo Lanari
EGU General Assembly Conference Abstracts, Apr 1, 2019
During the last decades, the availability of Synthetic Aperture Radar (SAR) satellite missions, s... more During the last decades, the availability of Synthetic Aperture Radar (SAR) satellite missions, such as the ERS-1/2 and ENVISAT ones operating at C-band who have worked since 1992 to 2011, as well as the X-band COSMO-SkyMed and TerraSAR-X constellations, up to the brand new Sentinel-1 mission, have strongly contributed to SAR data diffusion and popularity in the generation of different studies at different scales and in different research fields. One of the most popular SAR technique is the one referred to as Differential SAR Interferometry (DInSAR), which allows measuring with centimeter accuracy the Earth's surface deformation entity related to both natural and man-made hazards. Nowadays, with the increasing of SAR data availability provided by Sentinel-1 constellation of Copernicus European Program, which is composed by two twin satellites operating in C-band since 2014 and 2016, with a repeat pass of 6 days and with a global (i.e. worldwide) data acquisition policy, the SAR EO scenario is becoming more and more operational, thus mainly providing support for natural hazards monitoring. This allows, in theory, and disposing of sufficient computing power, the EO community to monitor, for instance, the deformation of every volcano or to obtain co-seismic displacement maps in a short time frame and anywhere in the world. Accordingly, in this work, we present a fully automatic and fast processing service for the generation of co-seismic displacement maps by using Sentinel-1 data. The implemented system is completely unsupervised and is triggered by the all significant (i.e. larger than a defined magnitude) seismic event registered by the online catalog as those provided by the United States Geological Survey (USGS) and the National Institute of Geophysics and Volcanology of Italy (INGV). The service has been specifically designed to operate for Civil Protection purposes. The generated DInSAR measurements are made available to the geoscience community through the EPOS Research Infrastructure and they will contribute to the creation of a global database of co-seismic displacement maps. Finally, it is worth noting that the developed system relies on widely common IT methods and protocols and is not specifically tied to a defined computing architecture, thus implying its portability, in view also of the European Commission Data and Information Access Services (DIAS) where satellite data (mainly Sentinel) and processing facilities are co-located to reduce the data transfer time during their processing.
2015 AGU Fall Meeting, Dec 14, 2015
EGU General Assembly Conference Abstracts, Apr 1, 2015
In a recent publication Ansari et al. (2021) [1] claim (see, in particular, the Discussion and Re... more In a recent publication Ansari et al. (2021) [1] claim (see, in particular, the Discussion and Recommendation Section in their article) that the advanced differential SAR interferometry (InSAR) algorithms for surface deformation retrieval, based on the small baseline approach, are affected by systematic biases in the generated InSAR products. Therefore, to avoid such biases, they recommend a strategy primarily focused on excluding "the short temporal baseline interferograms and using long baselines to decrease the overall phase errors". In particular, among various techniques, Ansari et al. (2021) [1] identify the solution presented by Manunta et al. (2019) [2] as a small baseline advanced InSAR processing approach where the presence of the above-mentioned biases (referred to as a fading signal) compromises the accuracy of the retrieved InSAR deformation products. We show that the claim of Ansari et al. (2021) [1] is not correct (at least) for what concerns the mentioned approach discussed by Manunta et al. (2019) [2]. In particular, by processing the Sentinel-1 dataset relevant to the same area in Sicily (southern Italy) investigated by Ansari et al. (2021) [1], we demonstrate that the generated InSAR products do not show any significant bias.
AGU Fall Meeting Abstracts, Dec 1, 2016
AGU Fall Meeting Abstracts, Dec 1, 2016
EGU General Assembly Conference Abstracts, Apr 1, 2018
We analysed the seismic sequence that affects the Umbria-Marche Apennine (Central Italy) since Au... more We analysed the seismic sequence that affects the Umbria-Marche Apennine (Central Italy) since August 2016, focusing on the Amatrice and the Norcia mainshocks. We investigate the ground deformation pattern and the source geometry responsible of the 2016 Central Italy seismic sequence by joint exploiting the multisensors and multiorbits satellite measurements (i.e. ALOS 2; e.g. Cheloni et al., 2017) and their integration with the available geological/structural and seismological data. Starting from DInSAR (i.e. ALOS 2) and seismological data (i.e. hypocentral distribution and available focal mechanisms), we computed the rock volumes involved during the earthquake nucleation processes and delimited between the main fault and by an antithetic fault, as suggested by earthquakes hypocentral distribution. In particular, in this work we calculated both the collapsed rock volume and the consecutive uplifted rock volume. In fact, DInSAR results highlight two different ground deformation within the hangingwall block: a larger zone and a smaller area affected by significant subsidence phenomena and by uplift processes, respectively. The Amatrice-Norcia seismogenic area is inserted in the tectonic setting of the Umbria-Marche Apennine. The seismic sequence began with the Mw 6.0 Amatrice earthquake, nucleated on August 24th, 2016 along the Mt. Gorzano extensional fault (e.g., Lavecchia et al., 2016). Then, on October 26th, two seismic events, occurred with Mw 5.4 and Mw 5.9 respectively, nucleated nearby Ussita and Visso (Chiaraluce et al., 2017), activating another major fault called the Mt. Vettore Fault System. Finally, on October 30th the largest event of the sequence (Mw 6.5) occurred near the town of Norcia along the Mt. Vettore Fault System. To estimate the volumes involved in the earthquake processes and starting from the DinSAR measurements, we employed three different methods (based on mathematical laws) and we obtained comparable results. Our results highlight a mass deficit within the crustal volume involved during the earthquake. Specifically, we observe a volume loss in response to a high strain rate deformation (i.e., during the earthquake nucleation). We suggest that the sudden closure of previously open fractures at depth can account for the observed volume loss. These fractures could be localized within a fractured and dilated zone located antithetically respect to the main fault. According to Doglioni et al. (2015), when the stresses related to gravitational energy exceed the strength of the fractured and dilated zone the rock volume collapses slipping along the main fault and generating the earthquake
EGU General Assembly Conference Abstracts, Apr 1, 2017
EGU General Assembly Conference Abstracts, Apr 1, 2015
AGU Fall Meeting Abstracts, Dec 1, 2019
EGU General Assembly Conference Abstracts, Apr 1, 2019
The Virunga Volcanoes is the first Supersite established on the African continent in a highly pop... more The Virunga Volcanoes is the first Supersite established on the African continent in a highly populated Multi-hazards region. This permanent Supersite was established in a critical context as little was known about the Virunga hazards sources and their dynamics, and little done as measures to evaluate, mitigate and reduce their impacts. Similarly, the active volcanoes are poorly studied and monitored, because of the lack of both qualified human resources and appropriate infrastructures. Therefore, the establishment of the "Virunga Volcanoes Supersite" aimed mostly at helping put together local and international scientists and agencies; support them to access to Earth Observatory (EO) data and potentially to equipment for ground-based data collection, as well as the building of a pool of collaboration. The expectation was that the above-mentioned collaborations and supports would improve the early warning capacity of the local scientists and agencies involved in Natural Haz...
IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium, 2019
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Papers by Riccardo Lanari