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D. Remy M. Falvey S. Bonvalot M. Chlieh G. Gabalda J.-L. Froger D. Legrand 《Journal of South American Earth Sciences》2011,31(2-3):214-226
The use of Synthetic Aperture Radar interferometry (InSAR) in northern Chile, one of the most seismically active regions in the world, is of great importance. InSAR enables geodesists not only to accurately measure Earth’s motions but also to improve fault slip map resolution and our knowledge of the time evolution of the earthquake cycle processes. Fault slip mapping is critical to better understand the mechanical behavior of seismogenic zones and has fundamental implications for assessing hazards associated with megathrust earthquakes. However, numerous sources of errors can significantly affect the accuracy of the geophysical parameters deduced by InSAR. Among them, atmospheric phase delays caused by changes in the distribution of water vapor can lead to biased model parameter estimates and/or to difficulties in interpreting deformation events captured with InSAR. The hyper-arid climate of northern Chile might suggest that differential delays are of a minor importance for the application of InSAR techniques. Based on GPS, Moderate Resolution Imaging Spectroradiometer (MODIS) data our analysis shows that differential phase delays have typical amplitudes of about 20 mm and may exceptionally exceed 100 mm and then may impact the inferences of fault slip for even a Mw 8 earthquakes at 10% level. In this work, procedures for mitigating atmospheric effects in InSAR data using simultaneous MODIS time series are evaluated. We show that atmospheric filtering combined with stacking methods are particularly well suited to minimize atmospheric contamination in InSAR imaging and significantly reduce the impact of atmospheric delay on the determination of fundamental earthquake parameters. 相似文献
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M. Ioualalen P. Arreaga-Vargas N. Pophet M. Chlieh K. Ilayaraja J. Ordoñez W. Renteria N. Pazmiño 《Pure and Applied Geophysics》2010,167(10):1205-1214
A numerical simulation of the 26th December, 2004 Indian Ocean tsunami of the Tamil Nadu coastal zone is presented. The simulation approach is based on a fully nonlinear Boussinesq tsunami propagation model and included an accurate computational domain and a robust coseismic source. The simulation is first confronted to available tide gauge and runup observations. The agreement between observations and the predicted wave heights allowed a reasonable validation of the simulation. As a result, a full picture of the tsunami impact is provided over the entire coastal zone Tamil Nadu. The processes responsible for coastal vulnerability are discussed. 相似文献
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M. Ioualalen T. Monfret N. Béthoux M. Chlieh G. Ponce Adams J.-Y. Collot C. Martillo Bustamante K. Chunga E. Navarrete G. Montenegro G. Solis Gordillo 《Marine Geophysical Researches》2014,35(4):361-378
The North-Andean subduction zone generates recurrent tsunamigenic earthquakes. The seismicity is usually considered to be segmented because of different specific morphological features of the Nazca Plate driving the subduction motion. Most of the recent powerful earthquakes in the margin were located in its northern part. To the south, the region of the Gulf of Guayaquil, only (undocumented) three events in 1901, 1933 and 1953 were possibly powerful and tsunamigenic. Here we are interested in the tsunami signature due to local seismicity. Two realistic earthquake scenarios (Mw = 7 and Mw = 7.5) taking into account the hypothesized segmentation of the area are proposed. Their return period is supposed to be intra-centenary. Then, a larger magnitude unsegmented Mw = 8 scenario is computed (half-millennium return period). The interior of the Gulf of Guayaquil as well as the Santa Elena Peninsula are sheltered areas including numerous coastal infrastructures and the city of Guayaquil. It is predicted that potential flooding would occur at high tide only for both segmented and unsegmented scenarios in (1) south of Playas with however only a few centimeters of wave height and (2) Chanduy (a few meters). Both are important zones of coastal farms. 相似文献
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