scholarly journals Seismic Anisotropy Reveals a Dynamic Link Between Adjacent Magmatic Segments Prior to Dyke Intrusion

2018 ◽  
Vol 123 (11) ◽  
pp. 9800-9816 ◽  
Author(s):  
Finnigan Illsley-Kemp ◽  
Tim Greenfield ◽  
Derek Keir
Keyword(s):  
Seismic Anisotropy ◽  
Dyke Intrusion ◽  
Dynamic Link

Reverse time migration in tilted transversely isotropic media

2020 ◽  
Vol 38 (2) ◽  
Author(s):  
Razec Cezar Sampaio Pinto da Silva Torres ◽  
Leandro Di Bartolo
Keyword(s):  
Seismic Anisotropy ◽  
Synthetic Data ◽  
Transversely Isotropic ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Computer Clusters ◽  
Time Migration ◽  
Transversely Isotropic Media ◽  
Isotropic Media ◽  
Tti Media

ABSTRACT. Reverse time migration (RTM) is one of the most powerful methods used to generate images of the subsurface. The RTM was proposed in the early 1980s, but only recently it has been routinely used in exploratory projects involving complex geology – Brazilian pre-salt, for example. Because the method uses the two-way wave equation, RTM is able to correctly image any kind of geological environment (simple or complex), including those with anisotropy. On the other hand, RTM is computationally expensive and requires the use of computer clusters. This paper proposes to investigate the influence of anisotropy on seismic imaging through the application of RTM for tilted transversely isotropic (TTI) media in pre-stack synthetic data. This work presents in detail how to implement RTM for TTI media, addressing the main issues and specific details, e.g., the computational resources required. A couple of simple models results are presented, including the application to a BP TTI 2007 benchmark model.Keywords: finite differences, wave numerical modeling, seismic anisotropy. Migração reversa no tempo em meios transversalmente isotrópicos inclinadosRESUMO. A migração reversa no tempo (RTM) é um dos mais poderosos métodos utilizados para gerar imagens da subsuperfície. A RTM foi proposta no início da década de 80, mas apenas recentemente tem sido rotineiramente utilizada em projetos exploratórios envolvendo geologia complexa, em especial no pré-sal brasileiro. Por ser um método que utiliza a equação completa da onda, qualquer configuração do meio geológico pode ser corretamente tratada, em especial na presença de anisotropia. Por outro lado, a RTM é dispendiosa computacionalmente e requer o uso de clusters de computadores por parte da indústria. Este artigo apresenta em detalhes uma implementação da RTM para meios transversalmente isotrópicos inclinados (TTI), abordando as principais dificuldades na sua implementação, além dos recursos computacionais exigidos. O algoritmo desenvolvido é aplicado a casos simples e a um benchmark padrão, conhecido como BP TTI 2007.Palavras-chave: diferenças finitas, modelagem numérica de ondas, anisotropia sísmica.

LINKING LITHOLOGY, STRUCTURE, AND ROCK PROPERTIES TO OBSERVED SEISMIC ANISOTROPY IN COLORADO ROCKY MOUNTAIN CRUST

2019 ◽  
Author(s):  
Michael G. Frothingham ◽  
◽  
Kevin H. Mahan ◽  
Vera Schulte-Pelkum ◽  
Jonathan S. Caine
Keyword(s):  
Seismic Anisotropy ◽  
Rocky Mountain ◽  
Rock Properties

scholarly journals The competing effects of olivine and orthopyroxene CPO on seismic anisotropy

2021 ◽  
pp. 228954
Author(s):  
Rachel E. Bernard ◽  
Vera Schulte-Pelkum ◽  
Whitney M. Behr
Keyword(s):  
Seismic Anisotropy

Oceanic crustal flow in Iceland observed using seismic anisotropy

2021 ◽  
Vol 14 (3) ◽  
pp. 168-173
Author(s):  
Omry Volk ◽  
Robert S. White ◽  
Simone Pilia ◽  
Robert G. Green ◽  
John Maclennan ◽  
...  
Keyword(s):  
Seismic Anisotropy

Effects of shoulder translation on lumbar moment for two dimensional modeling strategies during lifting

1998 ◽  
Vol 1 (3) ◽  
pp. 173-187
Author(s):  
Wayne J. Albert ◽  
Joan M. Stevenson ◽  
Geneviève A. Dumas ◽  
Roger W. Wheeler
Keyword(s):  
Sagittal Plane ◽  
Tracking System ◽  
Vertical Direction ◽  
Two Dimensional ◽  
Model Type ◽  
Trunk Acceleration ◽  
Analysis System ◽  
Trunk Orientation ◽  
Shoulder Position ◽  
Dynamic Link

The objectives of this study were to: 1) develop a dynamic 2D link segment model for lifting using the constraints of four sensors from an electromagnetic motion analysis system; 2) evaluate the magnitude of shoulder movement in the sagittal plane during lifting; and 3) investigate the effect of shoulder translation on trunk acceleration and lumbar moments calculated by the developed model and comparing it with two separate 2D dynamic link segment models. Six women and six men lifted loads of 2 kg, 7 kg, 12 kg and 2 kg, 12 kg, 22 kg respectively, under stoop, squat and freestyle conditions. Trunk orientation and position, as well as shoulder position were monitored during all lifts using the Polhemus FASTRAK\trdmk. Results indicated that average range of motion was 0.05 ± 0.02 m in the horizontal direction and 0.03 ± 0.02 m in the vertical direction. Shoulder position relative to T1 was located 0.07 ± 0.02 m anteriorly, and 0.02 ± 0.04 m superiorly (0.06 and 0.00 m for males and 0.08 and 0.04 m for females, respectively). To estimate the effect of shoulder motion on trunk acceleration and L5/S1 moments, three two-dimensional dynamic link segment models were developed within the constraints of the electromagnetic tracking system and compared. Trunk segment endpoints were defined as L5/S1 and either T1 or shoulder depending on model type. For trunk accelerations, average differences between models were greater than 40 deg/s² in 70.4% trunk accelerations did not translate into significantly different moment calculations between models. Average peak dynamic L5/S1 moment differences between models were smaller than 4 Nm for all lifting conditions which failed to be statistically significant (p>0.05). The model type did not have a statistically significant effect on peak L5/S1 moments. Therefore, despite important shoulder joint translations, peak L5/S1 moments were not significantly affected.

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