Monitoring Geohazards Using On-Demand And Systematic Services On Esa’s Geohazards Exploitation Platform

Foumelis, Michael; Παπαδοπουλου, Θεοδώρα; Bally, Philippe; Pacini, Fabrizio; Provost, Floriane; Patruno, Jolanda

doi:10.1109/igarss.2019.8898304

Cited by 32 publications

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“…1c,d) was produced using 33 descending Sentinel-1 scenes acquired between October 2018 and April 2019. The computation was performed via the Parallel Small Baseline tools provided by the Geohazards Exploitation Platform 22,23 (P-SBAS). The surface motion derived from SAR interferometry are projected along the Sentinel-1 line of sight (LOS).…”

Section: Observationsmentioning

confidence: 99%

Sentinel optical and SAR data highlights multi-segment faulting during the 2018 Palu-Sulawesi earthquake (Mw 7.5)

Bacques

Michele

Foumelis

et al. 2020

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The main active tectonic structure in the western part of Central Sulawesi (Indonesia) is the left-lateral Palu-Koro strike-slip fault. Its offshore section was thought not to have broken during the M w 7.5 Palu Earthquake on 28 September 2018, challenging the established knowledge of the tectonic setting at this location. Here, we use Sentinel-1 SAR interferometry to produce a map of the ground velocities in the area of the M w 7.5 earthquake for the seven months following the 2018 earthquake. We show evidence of surface deformation along the western coast of the Palu bay, indicating that the Palu Koro offshore fault section might have contribute to or been affected by the earthquake. As the possibility of multi-segment ruptures is a high concern in the area because of the high seismic and tsunami hazard, we present here, a fault model that includes the offshore section of the Palu-Koro fault. Thanks to four independents space-based geodetics measurements of the co-seismic displacement (Sentinel-1 and Sentinel-2 correlograms) we constrain the 3D co-seismic ground displacements. The modeling of these displacements allows us to estimate the co-seismic fault slip amplitude and geometry at depth. At the end, we consider the multi-segment faulting scenario, including the offshore section of the Palu-Koro fault, as a plausible model to explain the submarine landslides and the tsunamis. This study also gives the opportunity to observe a super-shear earthquake in the context of a complex fault network and implies an increase in the probability of submarine landslides within the bay in the forthcoming years. On 28 September 2018, a large tsunamigenic earthquake (M w 7.5) struck Sulawesi Island (Indonesia) near the Minahasa Peninsula 1,2 (Fig. 1a,b). The earthquake caused massive damages in Palu City, including dramatic onshore gravitational instabilities, soil liquefaction and a deadly tsunami 3-7. The Sulawesi island, in southeast Asia, is known to be a highly seismogenic area since it lies within a complex fault system where the Australian, Pacific, Philippine and Sunda Plates converge in an area of about 500 km diameter. The main active structure onshore in the western part of Central Sulawesi is the left-lateral NNW-SSE trending Palu-Koro strike-slip fault (PKF) that forms the boundary between the North Sula and Makassar micro-blocks 8,9 (Fig. 1a). During interseismic periods, it shows a transtensive behavior characterized by the presence of a pull-apart structure in the area of Palu city 8. Studies based on Global Navigation Satellite System (GNSS) have shown that motion on the Northern sector of the Sulawesi region is marked by a 40 mm.yr −1 left-lateral strike slip along the PKF 8,10-12. Therefore, the PKF is thought to partially accommodate the resulting interseismic stress load as six major earthquakes occurred along this fault within the past century (

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Section: Observationsmentioning

confidence: 99%

Sentinel optical and SAR data highlights multi-segment faulting during the 2018 Palu-Sulawesi earthquake (Mw 7.5)

Bacques

Michele

Foumelis

et al. 2020

Sci Rep

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“…nasa. gov), whereas others also provide thematic exploitation and e-collaboration capabilities (Foumelis et al 2019).…”

Section: Spaceborne Imaging Geodesymentioning

confidence: 99%

“…Following the event, the Aristotle University of Thessaloniki (AUTh) initiated DInSAR processing using several on-demand services hosted on the Geohazards Exploitation Platform (GEP, https:// geoha zards-tep. eu) (Foumelis et al 2019). It was applied to map the spatial distribution of coseismic ground displacements (ESA Sentinel Online 2020).…”

Section: Introductionmentioning

confidence: 99%

On rapid multidisciplinary response aspects for Samos 2020 M7.0 earthquake

et al. 2021

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Following the M 7.0 earthquake that struck the Greek island of Samos and Turkey's western coast, causing extensive damage and casualties, we combined existing knowledge geodatabases concerning historical seismicity and rupture zones with seismological and geodetic measurements as well as with modelling and in situ observations, to provide an assessment of rapid response to the seismic event. In this paper, we demonstrate that in the frame of the gradual provision of information from the individual scientific disciplines, taking into account their respective potential and limitations, a multidisciplinary approach is able to address more efficiently rapid response issues in order to allow effective preliminary interpretation of the earthquake activity, even within the first 24 h of the event. It focuses on the assessment of the timely provision of information by each discipline, evaluating the access to primary data sources as well as the maturity of the techniques in terms of accuracy and rapid data processing. Within a period of less than a week, several constraints were partially compensated for, allowing the delivery of more robust results and interpretation. The study highlights the readiness level of the various domains that has been significantly improved over the past years, including rapid seismological solutions, systematic availability of free and open Earth Observation data and on-demand online processing through dedicated platforms. Their combination with routinely applied inversion modelling and timely in situ observation is leading to improved operational response levels. Supplementary Information The online version contains supplementary material available at 10.1007/s11600-021-00578-6.

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“…images were processed to extract patterns of radar backscatter change due to flooding and drying out in the cross-and post-event SAR image pairs. The processing was performed using the SNAC-SNAP S-1 GRD Amplitude Change processing tool 38 developed by the European Space Agency (ESA) and available in ESA's Geohazards Exploitation Platform (GEP) 39 . The SNAC tool ingests pairs of Sentinel-1 images in GRD format and, after co-registration, calibration and terrain correction, generates calibrated and terrain corrected [decibel, dB] slave and master backscatter products (i.e.…”

Section: Methodsmentioning

confidence: 99%

Poorly known 2018 floods in Bosra UNESCO site and Sergiopolis in Syria unveiled from space using Sentinel-1/2 and COSMO-SkyMed

Tapete

Cigna

2020

Sci Rep

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The instability situation affecting the Middle East poses threats to preservation of cultural heritage. Mapping efforts based on satellite imagery currently concentrate more on recording human-induced damage than impacts of unforeseen natural events (e.g. floods). In 2018, the UNESCO World Heritage Site of Bosra and the landscape of Sergiopolis-Resafa in Syria were flooded after heavy rainfall. While the first incident was reported by heritage organisations (although information was limited to the main monument), the second event was completely unknown. Using optical and radar satellite images from the European Commission's Copernicus Sentinels fleet and the Italian Space Agency's COSMO-SkyMed constellation, we prove that these data are an enormous reservoir of information to assess comprehensively the duration, extent and severity of such natural events. In Bosra, several key assets were flooded besides the Roman Theatre, with waters taking from few days to several weeks to evacuate and dry out. In Sergiopolis, while the main ruins were sheltered by the fortification walls, the nearby floodplain was inundated. The floodwater-flow pattern resembled the simulations developed by archaeologists to prove the existence of an ancient system of embankments and dam. Our results suggest that many other events posing risk to heritage assets, otherwise unnoticed, may be unveiled if current satellite imagery archives, yet to analyse, are systematically screened.

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Monitoring Geohazards Using On-Demand And Systematic Services On Esa’s Geohazards Exploitation Platform

Cited by 32 publications

References 0 publications

Sentinel optical and SAR data highlights multi-segment faulting during the 2018 Palu-Sulawesi earthquake (Mw 7.5)

Sentinel optical and SAR data highlights multi-segment faulting during the 2018 Palu-Sulawesi earthquake (Mw 7.5)

On rapid multidisciplinary response aspects for Samos 2020 M7.0 earthquake

Poorly known 2018 floods in Bosra UNESCO site and Sergiopolis in Syria unveiled from space using Sentinel-1/2 and COSMO-SkyMed

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