Using ambient noise tomography and MAPS for high resolution stratigraphic identification in Hangzhou urban area

2021 ◽  
Vol 189 ◽  
pp. 104327
Author(s):  
Xinhua Chen ◽  
Hongyu Zhang ◽  
Changjiang Zhou ◽  
Jingyin Pang ◽  
Huaixue Xing ◽  
...  
2020 ◽  
Author(s):  
Ehsan Qorbani ◽  
Dimitri Zigone ◽  
Mark R. Handy ◽  
Götz Bokelmann ◽  

Abstract. We study the crustal structure under the Eastern and Southern Alps using ambient noise tomography. We use cross-correlations of ambient seismic noise between pairs of 71 permanent stations and 19 stations of the EASI profile to derive new high-resolution 3-D shear-velocity models for the crust. Continuous records from 2014 and 2015 are cross-correlated to estimate Green's functions of Rayleigh and Love waves propagating between the station pairs. Group velocities extracted from the cross-correlations are inverted to obtain isotropic 3-D Rayleigh and Love-wave shear-wave velocity models. Our high resolution models image several velocity anomalies and contrasts and reveal details of the crustal structure. Velocity variations at short periods correlate very closely with the lithologies of tectonic units at the surface and projected to depth. Low-velocity zones, associated with the Po and Molasse sedimentary basins, are imaged well to the south and north of the Alps, respectively. We find large high-velocity zones associated with the crystalline basement that forms the core of the Tauern Window. Small-scale velocity anomalies are also aligned with geological units such as the Ötztal and the Gurktal nappes of the Austroalpine nappes. Clear velocity contrasts in the Tauern Window along vertical cross-sections of the velocity model show the depth extent of the tectonic units and their bounding faults. A mid-crustal velocity contrast is interpreted as a manifestation of intracrustal decoupling in the Eastern Alps and decoupling between the Southern and Eastern Alps.


2018 ◽  
Vol 31 (5-6) ◽  
pp. 262-271
Author(s):  
Feng Liang ◽  
◽  
Lei Gao ◽  
Zhihui Wang ◽  
Tao Wang ◽  
...  

2016 ◽  
Vol 27 (3) ◽  
pp. 375 ◽  
Author(s):  
Kai-Xun Chen ◽  
Po-Fei Chen ◽  
Li-Wei Chen ◽  
Huajian Yao ◽  
Hongjian Fang ◽  
...  

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 640
Author(s):  
Olivier Oldrini ◽  
Patrick Armand ◽  
Christophe Duchenne ◽  
Sylvie Perdriel ◽  
Maxime Nibart

Accidental or malicious releases in the atmosphere are more likely to occur in built-up areas, where flow and dispersion are complex. The EMERGENCIES project aims to demonstrate the operational feasibility of three-dimensional simulation as a support tool for emergency teams and first responders. The simulation domain covers a gigantic urban area around Paris, France, and uses high-resolution metric grids. It relies on the PMSS modeling system to model the flow and dispersion over this gigantic domain and on the Code_Saturne model to simulate both the close vicinity and the inside of several buildings of interest. The accelerated time is achieved through the parallel algorithms of the models. Calculations rely on a two-step approach: the flow is computed in advance using meteorological forecasts, and then on-demand release scenarios are performed. Results obtained with actual meteorological mesoscale data and realistic releases occurring both inside and outside of buildings are presented and discussed. They prove the feasibility of operational use by emergency teams in cases of atmospheric release of hazardous materials.


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