scholarly journals PEMODELAN SEISMIK PADA STRUKTUR GEOLOGI KOMPLEKS MENGGUNAKAN METODE COMMON REFLECTION SURFACE (CRS)

2021 ◽  
Vol 7 (3) ◽  
pp. 164-177
Author(s):  
Ilham Dani ◽  
Mohammad Rachmat Sule
Keyword(s):  
Foot Wall ◽  
Common Reflection Surface ◽  
Reflector Surface

Pemodelan seismik merupakan tahap penting untuk memahami respon bawah permukaan bumi terhadap gelombang seismik yang digambarkan dalam bentuk energi seismik refleksi. Walaupun saat ini teknologi pengolahan data seismik telah meningkat dengan pesat, ketidakakuratan posisi reflektor dalam penampang seismik yang dihasilkan tetap saja sering ditemukan, terutama pada daerah dengan struktur geologi kompleks. Model geologi struktur kompleks pada penelitian ini mengacu pada arsitektur glasiotektonik di daerah Fur Knudeklint, Denmark yang memiliki banyak patahan dan lipatan dengan skala kecil. Hasil simulasi perambatan gelombang dengan metode penjalaran sinar dilakukan dari dua arah akuisisi berbeda menggunakan perangkat lunak Norsar 2D untuk mendapatkan seismogram sintetik. Data yang dihasilkan kemudian digunakan sebagai masukan untuk pengolahan data seismik secara konvensional maupun menggunakan metode Common Reflector Surface (CRS) Stack. Hasilnya menunjukkan bahwa akuisisi data dari arah foot wall memberikan citra reflektor yang lebih representatif dibandingkan dari arah sebaliknya. Penegasan kualitas reflektor terlihat jelas di tiga area utama, yaitu CDP 20-100, CDP 120-180 dan CDP 160-330. Dengan demikian, metode CRS Stack berhasil merekonstruksi reflektor-reflektor berupa lipatan kecil dan perlapisan tipis pada struktur geologi kompleks dengan kualitas lebih baik dibandingkan metode konvensional.

Real-time Closed-loop Active Surface Technology of a Large Radio Telescope

2022 ◽  
Vol 134 (1031) ◽  
pp. 015003
Author(s):  
Yong Zhang ◽  
Guoping Li ◽  
Guohua Zhou ◽  
Qishuai Lu ◽  
Heng Zuo ◽  
...  
Keyword(s):  
Real Time ◽  
Radio Telescope ◽  
Closed Loop ◽  
Preliminary Test ◽  
Active Surface ◽  
Angle Measurement ◽  
Quality Data ◽  
Surface Accuracy ◽  
Surface System ◽  
Reflector Surface

Abstract The surface accuracy of a large radio telescope’s primary reflector is easily affected by gravity and temperature change during observations. An active surface system is crucial to ensure the regular operation and high-quality data output of the radio telescope. We propose a real-time closed-loop active surface system including two components. The first component, a new type of photoelectric edge sensor, detects the angle change of the adjacent panels. The second component, the displacement actuator, adjusts the panels’ position and posture to compensate for the angle changes. So, over the entire observation, the closed-loop surface control system with these two components could actively maintain the primary reflector’s accuracy in real time. Using this approach, we constructed an experimental active surface system for the Xinjiang Qitai 110 m Radio Telescope (QTT) to test the maintenance of the surface accuracy. The angle measurement accuracy is better than 0.″2, and the positioning accuracy of the displacement actuator could achieve ±15 μm over the whole 50 mm stroke. The preliminary test results show that the accuracy requirements of the QTT’s primary reflector surface can be met using the active surface system we propose.

Velocity inversion by global optimization using finite-offset common-reflection-surface stacking applied to synthetic and Tacutu Basin seismic data

Geophysics ◽  
2019 ◽  
Vol 84 (2) ◽  
pp. R165-R174 ◽  
Author(s):  
Marcelo Jorge Luz Mesquita ◽  
João Carlos Ribeiro Cruz ◽  
German Garabito Callapino
Keyword(s):  
Objective Function ◽  
Real Data ◽  
Velocity Model ◽  
Data Sets ◽  
Layer By Layer ◽  
Velocity Inversion ◽  
Very Fast Simulated Annealing ◽  
Target Layer ◽  
Common Reflection Surface ◽  
The Mean

Estimation of an accurate velocity macromodel is an important step in seismic imaging. We have developed an approach based on coherence measurements and finite-offset (FO) beam stacking. The algorithm is an FO common-reflection-surface tomography, which aims to determine the best layered depth-velocity model by finding the model that maximizes a semblance objective function calculated from the amplitudes in common-midpoint (CMP) gathers stacked over a predetermined aperture. We develop the subsurface velocity model with a stack of layers separated by smooth interfaces. The algorithm is applied layer by layer from the top downward in four steps per layer. First, by automatic or manual picking, we estimate the reflection times of events that describe the interfaces in a time-migrated section. Second, we convert these times to depth using the velocity model via application of Dix’s formula and the image rays to the events. Third, by using ray tracing, we calculate kinematic parameters along the central ray and build a paraxial FO traveltime approximation for the FO common-reflection-surface method. Finally, starting from CMP gathers, we calculate the semblance of the selected events using this paraxial traveltime approximation. After repeating this algorithm for all selected CMP gathers, we use the mean semblance values as an objective function for the target layer. When this coherence measure is maximized, the model is accepted and the process is completed. Otherwise, the process restarts from step two with the updated velocity model. Because the inverse problem we are solving is nonlinear, we use very fast simulated annealing to search the velocity parameters in the target layers. We test the method on synthetic and real data sets to study its use and advantages.

Non-hyperbolic common reflection surface

2012 ◽  
Vol 61 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Sergey Fomel ◽  
Roman Kazinnik
Keyword(s):  
Common Reflection Surface

Fabrication of electrically-pumped resonance-cavity membrane-reflector surface-emitters on silicon

2013 ◽  
Author(s):  
Wenjuan Fan ◽  
Deyin Zhao ◽  
Santhad Chuwongin ◽  
Jung-Hun Seo ◽  
Hongjun Yang ◽  
...  
Keyword(s):  
Electrically Pumped ◽  
Reflector Surface ◽  
Resonance Cavity

scholarly journals Extending the usage of graphics processing units on the cloud for cost savings on seismic data regularization

2021 ◽  
Vol 38 (2) ◽  
Author(s):  
Nicholas Torres Okita ◽  
Tiago A. Coimbra ◽  
José Ribeiro ◽  
Martin Tygel
Keyword(s):  
Cloud Computing ◽  
Graphics Processing Units ◽  
Cost Savings ◽  
Data Sets ◽  
Computing Paradigm ◽  
Common Reflection Surface ◽  
User Demand ◽  
Computationally Intensive ◽  
Zero Offset ◽  
Graphics Processing

ABSTRACT. The usage of graphics processing units is already known as an alternative to traditional multi-core CPU processing, offering faster performance in the order of dozens of times in parallel tasks. Another new computing paradigm is cloud computing usage as a replacement to traditional in-house clusters, enabling seemingly unlimited computation power, no maintenance costs, and cutting-edge technology, dynamically on user demand. Previously those two tools were used to accelerate the estimation of Common Reflection Surface (CRS) traveltime parameters, both in zero-offset and finite-offset domain, delivering very satisfactory results with large time savings from GPU devices alongside cost savings on the cloud. This work extends those results by using GPUs on the cloud to accelerate the Offset Continuation Trajectory (OCT) traveltime parameter estimation. The results have shown that the time and cost savings from GPU devices’ usage are even larger than those seen in the CRS results, being up to fifty times faster and sixty times cheaper. This analysis reaffirms that it is possible to save both time and money when using GPU devices on the cloud and concludes that the larger the data sets are and the more computationally intensive the traveltime operators are, we can see larger improvements.Keywords: cloud computing, GPU, seismic processing. Estendendo o uso de placas gráficas na nuvem para economias em regularização de dados sísmicosRESUMO. O uso de aceleradores gráficos para processamento já é uma alternativa conhecida ao uso de CPUs multi-cores, oferecendo um desempenho na ordem de dezenas de vezes mais rápido em tarefas paralelas. Outro novo paradigma de computação é o uso da nuvem computacional como substituta para os tradicionais clusters internos, possibilitando o uso de um poder computacional aparentemente infinito sem custo de manutenção e com tecnologia de ponta, dinamicamente sob demanda de usuário. Anteriormente essas duas ferramentas foram utilizadas para acelerar a estimação de parâmetros do tempo de trânsito de Common Reflection Surface (CRS), tanto em zero-offset quanto em offsets finitos, obtendo resultados satisfatórios com amplas economias tanto de tempo quanto de dinheiro na nuvem. Este trabalho estende os resultados obtidos anteriormente, desta vez utilizando GPUs na nuvem para acelerar a estimação de parâmetros do tempo de trânsito em Offset Continuation Trajectory (OCT). Os resultados obtidos mostraram que as economias de tempo e dinheiro foram ainda maiores do que aquelas obtidas no CRS, sendo até cinquenta vezes mais rápido e sessenta vezes mais barato. Esta análise reafirma que é possível economizar tanto tempo quanto dinheiro usando GPUs na nuvem, e conclui que quanto maior for o dado e quanto mais computacionalmente intenso for o operador, maiores serão os ganhos de desempenho observados e economias.Palavras-chave: computação em nuvem, GPU, processamento sísmico. 

scholarly journals A Bluff-Shelter Site in Pontotoc County, Oklahoma

2000 ◽  
Author(s):  
H. R. Antle
Keyword(s):  
Rock Mass ◽  
Foot Wall ◽  
Fault Line ◽  
Multiple Fractures ◽  
The North ◽  
Shelter Site ◽  
Siliceous Material ◽  
Fault Lines ◽  
Sandstone Formation

In the wildly rugged hills near Canyon Springs, in southeastern Pontotoc County, Oklahoma, a unique sandstone formation has produced evidence of once sheltering a prehistoric people. Technically, the sandstone is of the Wilcox series, and is faulted to a position above the McLish limestone beneath which it normally lies. The fault line runs from the north southward a distance of 25 yards, then runs at right angles to the east for 40 yards. The sandstone ranges from 6 feet in height on the northern extremity to 35 feet along the southeastern portion. Multiple fractures, generally parallel to the fault lines, have been recemented with dissolved siliceous material to make a highly resistant formation. Erosion takes place by exfoliation, giving to the rock mass, at a distance, a granitic appearance. Because of slanting fracture lines, the foot-wall of the fault, overthrust as it is, has broken off in places to form huge over-hangs that afford plentiful protection from the weather. It was in such an area evidence of a prehistoric habitation was found.

Sign in / Sign up

Export Citation Format

Share Document