Very high-resolution seismic mapping of shallow gas in the Belgian coastal zone

2002 ◽  
Vol 22 (16) ◽  
pp. 2291-2301 ◽  
Author(s):  
T Missiaen ◽  
S Murphy ◽  
L Loncke ◽  
J.-P Henriet
Keyword(s):  
High Resolution ◽  
Coastal Zone ◽  
Shallow Gas ◽  
Very High

scholarly journals Fine-scale velocity distribution revealed by datuming of very-high-resolution deep-towed seismic data: Example of a shallow-gas system from the western Black Sea

Geophysics ◽  
2020 ◽  
Vol 85 (5) ◽  
pp. B181-B192 ◽  
Author(s):  
Florent Colin ◽  
Stéphan Ker ◽  
Bruno Marsset
Keyword(s):  
High Resolution ◽  
Black Sea ◽  
Seismic Data ◽  
Full Potential ◽  
Shallow Gas ◽  
Multichannel Data ◽  
Processing Algorithms ◽  
Very High ◽  
Water Depths ◽  
Seismic System

Very-high-resolution (VHR) marine seismic reflection helps to identify and characterize potential geohazards occurring in the upper part (300 m) of the subseafloor. Although the lateral and vertical resolutions achieved in shallow water depths ([Formula: see text]) using conventional surface-towed technology are adequate, these resolutions quickly deteriorate at greater water depths. The SYstème SIsmique de Fond (SYSIF), a multichannel deep-towed seismic system, has been designed to acquire VHR data (frequency bandwidth [220–1050 Hz] and vertical resolution of 0.6 m) at great water depths. However, the processing of deep-towed multichannel data is challenging because the source and the receivers are constantly moving with respect to each other according to the towing configuration. We have introduced a new workflow that allows the application of conventional processing algorithms to extended deep-towed seismic data sets. First, a relocation of the source and receivers is necessary to obtain a sufficiently accurate acquisition geometry. Variations along the profile in the depth of the deep-towed system result in a complex geometry in which the source and receiver depth vary separately and do not share the same acquisition datum. We have designed a dedicated datuming algorithm to shift the source and receivers to the same datum. Thus, the procedure allows the application of conventional processing algorithms to perform velocity analysis and depth imaging and therefore allows access to the full potential of the seismic system. We have successfully applied this methodology to deep-towed multichannel data from the western Black Sea. In particular, the derived velocity model highlights shallow gas charged anticline structures with unrivaled resolution.

Very High Resolution Analysis of the Dynamics of a Coronal Plasmoid

1994 ◽  
Vol 144 ◽  
pp. 593-596
Author(s):  
O. Bouchard ◽  
S. Koutchmy ◽  
L. November ◽  
J.-C. Vial ◽  
J. B. Zirker
Keyword(s):  
High Resolution ◽  
Solar Eclipse ◽  
Total Solar Eclipse ◽  
Field Of View ◽  
Small Field ◽  
High Resolution Analysis ◽  
Ccd Observations ◽  
Resolution Analysis ◽  
Very High ◽  
Small Field Of View

AbstractWe present the results of the analysis of a movie taken over a small field of view in the intermediate corona at a spatial resolution of 0.5“, a temporal resolution of 1 s and a spectral passband of 7 nm. These CCD observations were made at the prime focus of the 3.6 m aperture CFHT telescope during the 1991 total solar eclipse.

Three-dimensional fault geometry and kinematics of the 2008 M 7.1 Yutian earthquake revealed by very-high resolution satellite stereo imagery

2019 ◽  
Vol 232 ◽  
pp. 111300
Author(s):  
Xiaogang Song ◽  
Nana Han ◽  
Xinjian Shan ◽  
Chisheng Wang ◽  
Yingfeng Zhang ◽  
...  
Keyword(s):  
High Resolution ◽  
Three Dimensional ◽  
Fault Geometry ◽  
Stereo Imagery ◽  
Very High ◽  
Geometry And Kinematics

scholarly journals Object Oriented Classification for Mapping Mixed and Pure Forest Stands Using Very-High Resolution Imagery

2021 ◽  
Vol 13 (13) ◽  
pp. 2508
Author(s):  
Loredana Oreti ◽  
Diego Giuliarelli ◽  
Antonio Tomao ◽  
Anna Barbati
Keyword(s):  
High Resolution ◽  
Spatial Scales ◽  
Parametric Method ◽  
Mixed Forest ◽  
Mixed Stands ◽  
Mapping Unit ◽  
Mixed Forests ◽  
High Resolution Imagery ◽  
Very High Resolution Imagery ◽  
Very High

The importance of mixed forests is increasingly recognized on a scientific level, due to their greater productivity and efficiency in resource use, compared to pure stands. However, a reliable quantification of the actual spatial extent of mixed stands on a fine spatial scale is still lacking. Indeed, classification and mapping of mixed populations, especially with semi-automatic procedures, has been a challenging issue up to date. The main objective of this study is to evaluate the potential of Object-Based Image Analysis (OBIA) and Very-High-Resolution imagery (VHR) to detect and map mixed forests of broadleaves and coniferous trees with a Minimum Mapping Unit (MMU) of 500 m2. This study evaluates segmentation-based classification paired with non-parametric method K- nearest-neighbors (K-NN), trained with a dataset independent from the validation one. The forest area mapped as mixed forest canopies in the study area amounts to 11%, with an overall accuracy being equal to 85% and K of 0.78. Better levels of user and producer accuracies (85–93%) are reached in conifer and broadleaved dominated stands. The study findings demonstrate that the very high resolution images (0.20 m of spatial resolutions) can be reliably used to detect the fine-grained pattern of rare mixed forests, thus supporting the monitoring and management of forest resources also on fine spatial scales.

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