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Coverage of the Taiwan island by InSAR with Sentinel-1 and ALOS images / Bénédicte Fruneau (2019)  

Public Titre : Coverage of the Taiwan island by InSAR with Sentinel-1 and ALOS images Type de document : Article/Communication Auteurs : Bénédicte Fruneau , Auteur ; Erwan Pathier, Auteur ; Marie-Pierre Doin, Auteur ; Jyr-Ching Hu, Auteur ; Hsin Tung, Auteur Editeur : Champs/Marne : Université Paris-Est Marne-la-Vallée UPEM Année de publication : 2019 Conférence : LPS 2019, ESA Living Planet Symposium 13/05/2019 17/05/2019 Milan Italie programme sans actes Langues : Français (fre) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] image ALOS-PALSAR [Termes IGN] image Sentinel-SAR [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] surveillance géologique [Termes IGN] Taïwan Résumé : (auteur) Taiwan Island, resulting from oblique collision between Philippine sea plate and Eurasian plate converging at a rate of about 8 cm per year, is one of the most active tectonic region in the world. With a subtropical environment, it is faced to different hazards, including earthquakes, debris flow, landslides, and flooding. The precise measurement of the present-day ground displacements at the scale of the whole Taiwan Island is thus essential in several domains of Earth Sciences, in particular for earthquake cycle study and earthquake hazard assessment, for subsidence and landslide monitoring, and also to better understand the kinematics and mechanics of mountain building. Taiwan benefits from a remarkable GNSS network. However, due to a complex geodynamical context and high strain rate, the pattern of deformation is not well solved by GNSS. In complement, INSAR shows its contribution with respect to GNSS, as it allows to dramatically increase the spatial information. Combining SAR dataset provided by ALOS-1, ALOS-2 and Sentinel-1 enables to generate consistent time series and dense maps of ground displacements by InSAR on the whole island over different periods. This possibility of long time series of observations is particularly interesting for earthquake cycle study. Our processing uses NSBAS interferometric chain (Doin et al., 2015), based on a SBAS approach, that includes several corrections applied before unwrapping, in particular correction of atmospheric delays predicted from the global atmospheric re-analysis ERA-Interim model, and local DEM error correction. These corrections are of particular importance as they reduce the variance of the phase across regions with high topographic gradients, like the Central Range in Taiwan, hence facilitating unwrapping step. Using the full archive of ALOS-1 PALSAR images, a first complete deformation map of Taiwan has been derived over the period 2007-2011. Our InSAR results offer an unprecedented continuous view of deformation field of the entire Island. For instance, in the Central Range, the LOS velocity map shows a clear pattern of deformation, consistent with a rapid uplift (cm/y) of the Central Range South of the island. This uplift, already partially documented by GPS and leveling, is clearly mapped here and seems to show an overall continuity. In southwestern Taiwan, the InSAR LOS velocity map provides a good coverage in the foothills area, revealing several localized areas of interseismic deformation that were overlooked in GNSS, and that can be correlated with tectonic structures. Among them, is the 15 km-long Lungchuan anticline, showing relative surface displacement toward satellite by several cm/year. Those observations, combined with a geological study and field survey (Le Beon et al., 2017), suggest the existence of a back-thrust fault that reaches the surface on western side of Lungchuan ridge and roots on the ~4 km deep Tainan detachment. This structure has also been activated during 2010 Mw 6.3 Jia-Shian Earthquake and the Meinong earthquake (02/05/2016, Mw6.4). A time series analysis can also be conducted on 2014-2018 period with Sentinel-1 data. Since end of 2014, we benefit from S1 SAR images, acquired in C-band, thus less favorable than PALSAR L-band on Taiwan Island. However, this drawback is balanced thanks to the high frequency of image acquisitions (12 days on Taiwan with S1-A and S1-B). We can also take advantage of the 2 different geometries of acquisition (both ascending and descending) to derive horizontal and vertical components of the deformation. The combination of ALOS and Sentinel-1 InSAR results, in addition to their high density of measure, covers different time periods and gives the opportunity to investigate temporal evolution of the deformation. Some areas, in particular in SW Taiwan, show changes in the tectonic deformation pattern, thus revealing transient behavior of some structures. Those observations can also be completed on several areas with previous ERS and Envisat INSAR results, offering an unique monitoring of more than 20 years. Numéro de notice : C2019-055 Affiliation des auteurs : LASTIG+Ext (2016-2019) Thématique : IMAGERIE Nature : Poster nature-HAL : ComSansActesPubliés-Unpublished DOI : sans En ligne : https://lps19.esa.int/NikalWebsitePortal/living-planet-symposium-2019/lps19/Agen [...] Format de la ressource électronique : vers le résumé Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96644

Innovative Methods and Products of the " Urbanization and Artificialization" Scientific Expertise Centre / Anne Puissant (2019)  

Public Titre : Innovative Methods and Products of the " Urbanization and Artificialization" Scientific Expertise Centre Type de document : Article/Communication Auteurs : Anne Puissant, Auteur ; Arnaud Le Bris , Auteur ; Vincent Thieron, Auteur ; Thomas Corpetti, Auteur ; Thibault Catry, Auteur ; Sébastien Gadal, Auteur ; Xavier Briottet , Auteur ; Remy Cression, Auteur ; Nicolas Baghdadi, Auteur ; Arnaud Sellé, Auteur Editeur : Paris : HAL Année de publication : 2019 Conférence : LPS 2019, ESA Living Planet Symposium 13/05/2019 17/05/2019 Milan Italie programme sans actes Importance : 2 p. Format : 21 x 30 cm Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Infrastructure de données [Termes IGN] données localisées [Termes IGN] empreinte écologique [Termes IGN] information scientifique et technique [Termes IGN] télédétection [Termes IGN] urbanisation [Termes IGN] utilisation du sol Résumé : (auteur) he THEIA Land Data and Services Centre (www.theia-land.fr) is a consortium of 12 French public institutions involved in Earth observation and environmental sciences (CEA, CEREMA, CIRAD, CNES, IGN, INRA, CNRS, IRD, Irstea, Météo France, AgroParisTech, and ONERA). THEIA has been initiated in 2012 with the objective of increasing the use of space data by the scientific community and the public actors. THEIA structured the French scientific community 1) through a mutualized Service and Data Infrastructure (SDI) distributed between several centers, allowing access to a variety of products; 2) through the setup of Regional Animation Networks (RAN) to federate and animate users (scientists and public / private actors) and 3) through Scientific Expertise Centres (SEC) clustering virtual research groups on a thematic domain. One of this SEC is the "Urbanization and Artificialization” Centre clustering experts in multi-sensor urban remote sensing. THEIA in collaboration with ODATIS (Data and Service for the Ocean), ForM@Ter (Data and Service for the Solid Earth), and AERIS (Data and Service for the Atmosphere) form the "Earth System" Research Infrastructure. The objective of this poster is to present recent (>2016) innovations of the URBAN SEC in terms of (1) development of algorithms useful for urban remote sensing using optical and SAR sensors, (2) validation of the urban products provided by the THEIA Land Service and Data Infrastructure, and (3) demonstration of user-tailored applications for urban studies. The Urban Expert Centre brings together researchers and engineers from several institutes: LIVE - Strasbourg, IGN-LaSTIG - Univ. Paris Est, CESBIO – Toulouse, LETG - Rennes, Irstea – Montpellier, TETIS - Montpellier, INP Bordeaux, IRD, ESPACE-DEV - Montpellier, ESPACE - Nice, ONERA. Research results and methods linked to (1) the detection and mapping of the urban footprint at an annual frequency; (2) the identification of urban fabrics, (3) the mapping of green networks within the cities. In parallel, the group proposes to summarize and identify relevant indicators (parameters) dedicated to urban planning and management. Numéro de notice : C2019-046 Affiliation des auteurs : LASTIG MATIS+Ext (2012-2019) Thématique : IMAGERIE Nature : Poster nature-HAL : ComSansActesPubliés-Unpublished DOI : sans En ligne : https://hal.archives-ouvertes.fr/hal-02135846 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95429