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DOI | 10.1029/2022JB026251 |
Referencing of Continental-Scale InSAR-Derived Velocity Fields: Case Study of the Eastern Tibetan Plateau | |
Lemrabet, Laetitia; Doin, Marie-Pierre; Lasserre, Cecile; Durand, Philippe | |
发表日期 | 2023 |
ISSN | 2169-9313 |
EISSN | 2169-9356 |
卷号 | 128期号:7 |
英文摘要 | The wealth of Sentinel-1 data in eastern Tibet allows to discuss whether InSAR-derived velocity maps measure ground motion in the ITRF reference frame with sufficient accuracy for large-scale tectonic applications. High elevation, moderate relief and low vegetation cover in eastern Tibet ensure reliable multi-temporal InSAR results. We automatically process seven 1,200 km long ascending and descending orbits, divided into 2 or 3 overlapping segments along-track. Linear phase ramps in range and azimuth are removed from interferograms. The ramps and the flattened interferograms are separately inverted into time series and analyzed. The ramps are modeled by their Solid Earth Tides (SET) contribution, seasonal variations, and a trend in time. SET oscillations are clearly visible in the ramp time series. Seasonal tidal amplifications of probable atmospheric origin are also evidenced. Ramp rates are shown to precisely quantify the plate motion of each segment in the ITRF reference frame. They are thus added back to the velocity maps before along-track merging. Then, a simple referencing procedure implying only a constant and a tilt in azimuth adjusted for each track is constrained by horizontal GNSS data. It allows straightforward vertical and horizontal decomposition. The quality of the merged and referenced data sets can then be quantitatively assessed at 1 mm/yr by the differences between InSAR and GNSS velocities and by the InSAR residuals on track overlaps. The vertical velocity field is dominated at first order by the effect of permafrost degradation, while the horizontal velocity highlights strain accumulation across major strike-slip faults in eastern Tibet. Plain Language Summary The imagery acquired by the Sentinel-1 satellites allows to map the earth surface displacement field with an unprecedented resolution in space and time. The radar interferometric technique (InSAR) allows to form time-series of electromagnetic wave delays between the satellite and the ground for each pixel of the radar footprint. We here analyze in details the differential delay time series at very large scale, that is, between the east and western parts (250 km apart), or between the southern and northern parts (700 km apart) of 30 satellite footprints in Eastern Tibet. We show that this differential delays are explained by the displacements due to tides of the Solid Earth and due to plate tectonic drift with respect to the orbit reference frame. The robust analysis of the largest-scale delay measurements allows to tie the InSAR velocity measurements to a reference frame with a minimum input from GNSS observations. InSAR-GNSS velocity measurements can then be compared and show an agreement within 1.4 mm/yr. Velocity maps from ascending and descending tracks are combined to obtain horizontal and vertical velocities. The maps display clearly the interseismic motion on faults and the effect of permafrost degradation and interannual hydrological fluctuations. |
关键词 | InSARITRFTibetinterseismiclarge-scale plate motionuncertainty assessment |
英文关键词 | INTERSEISMIC STRAIN; HAIYUAN FAULT; EARTHQUAKE; GPS; DEFORMATION; BEHAVIOR; TURKEY; SLIP |
WOS研究方向 | Geochemistry & Geophysics |
WOS记录号 | WOS:001151484200001 |
来源期刊 | JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH |
文献类型 | 期刊论文 |
条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/283074 |
作者单位 | Centre National de la Recherche Scientifique (CNRS); Universite Claude Bernard Lyon 1; Ecole Normale Superieure de Lyon (ENS de LYON); Communaute Universite Grenoble Alpes; Universite Grenoble Alpes (UGA); Centre National de la Recherche Scientifique (CNRS); Institut de Recherche pour le Developpement (IRD); Universite Gustave-Eiffel; Universite Savoie Mont Blanc |
推荐引用方式 GB/T 7714 | Lemrabet, Laetitia,Doin, Marie-Pierre,Lasserre, Cecile,et al. Referencing of Continental-Scale InSAR-Derived Velocity Fields: Case Study of the Eastern Tibetan Plateau[J],2023,128(7). |
APA | Lemrabet, Laetitia,Doin, Marie-Pierre,Lasserre, Cecile,&Durand, Philippe.(2023).Referencing of Continental-Scale InSAR-Derived Velocity Fields: Case Study of the Eastern Tibetan Plateau.JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,128(7). |
MLA | Lemrabet, Laetitia,et al."Referencing of Continental-Scale InSAR-Derived Velocity Fields: Case Study of the Eastern Tibetan Plateau".JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 128.7(2023). |
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