Titre : |
Present-day deformation in Taiwan mountain belt as monitored by InSAR |
Type de document : |
Article/Communication |
Auteurs : |
Bénédicte Fruneau , Auteur ; Erwan Pathier, Auteur ; Marie-Pierre Doin, Auteur ; Jyr-Ching Hu, Auteur ; Hsin Tung, Auteur |
Editeur : |
Paris : Agence Spatiale Européenne ASE / European Space Agency ESA |
Année de publication : |
2017 |
Conférence : | Fringe 2017, 10th International Workshop on Advances in the Science and Applications of SAR Interferometry and Sentinel-1 InSAR 05/06/2017 09/06/2017 Helsinki Finlande programme sans actes | Langues : |
Anglais (eng) |
Descripteur : |
[Vedettes matières IGN] Traitement d'image radar et applications [Termes descripteurs IGN] déformation de la croute terrestre [Termes descripteurs IGN] interféromètrie par radar à antenne synthétique [Termes descripteurs IGN] surveillance géologique [Termes descripteurs IGN] Taïwan
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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. In the framework of our complete mapping of Taiwan Island with InSAR, we use in this study the full archive of SAR data acquired by ALOS-1 satellite on the 2007-2011 period. ALOS L-band data are very effective in the vegetated and hilly Taiwan environment. SAR images are processed through a small baseline approach with NSBAS interferometric chain (Doin et al., 2015). It 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, hence preventing unwrapping errors. Unwrapping process is also performed using a specific scheme, taking into account the information of colinearity. Thanks to this careful processing, we are able to unwrap across the Central Range, a challenging area with more than 3000m of topographic ranges. InSAR offers an unprecedented continuous view of deformation field of a large part of the Central Range. LOS velocity map obtained on track 446 shows a clear pattern of deformation, consistent with a rapid uplift 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 overall continuity. However, details of this map should be analyzed with caution.This is a real contribution of InSAR with respect to GPS, with a dramatic increase of the spatial information: even if the density of GPS stations is high in Taiwan, they are mostly distributed around the Central Range, and do not offer such spatial sampling.On this track, InSAR results allow also to connect spatially south western part of Taiwan, mapping the deformations of the Foothills and the Coastal Plain, and the southern end of the Longitudinal Valley, showing aseismic creep. |
Numéro de notice : |
C2017-054 |
Affiliation des auteurs : |
UPEM-LaSTIG+Ext (2016-2019) |
Autre URL associée : |
vers HAL |
Thématique : |
IMAGERIE |
Nature : |
Poster |
nature-HAL : |
Poster-avec-CL |
DOI : |
sans |
Permalink : |
https://documentation.ensg.eu/index.php?lvl=notice_display&id=96651 |
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