LONG RANGE SEISMIC DATA FROM THE LAKE SUPERIOR SEISMIC EXPERIMENT 1963- 1964

1966 ◽  
Author(s):  
Robert H. Mansfield ◽  
Jack F. Evernden
2020 ◽  
Vol 46 (2) ◽  
pp. 93
Author(s):  
Jan Barmuta ◽  
Monika Korbecka ◽  
Piotr Hadro ◽  
Krzysztof Pieniądz ◽  
Michał Stefaniuk ◽  
...  

An attempt was made to describe the quality of the stacked seismic data semi-quantitatively with respect to the spacing of shot and receiver lines. The methods used included: signal-to-noise ratio calculation, seismic-to-well tie accuracy, wavelet extraction effectiveness and reliability of semi-automated interpretation of seismic attributes. This study was focused on the Ordovician-Silurian interval of the Lublin Basin, Poland, as it was considered as a main target for the exploration of unconventional hydrocarbon deposits. Our results reconfirm the obvious dependency between the density of the acquisition parameters and data quality. However, we also discovered that the seismic data quality is less affected by the shot line spacing than by comparable receiver line spacing. We attributed this issue to the fact of the higher irregularity of the shot points than receiver points, imposed by the terrain accessibility. We have also proven that the regularity of receiver and shot point distributionis crucial for the reliable interpretation of structural seismic attributes, since these were found to be highly sensitive to the acquisition geometry.


1994 ◽  
Vol 31 (4) ◽  
pp. 652-660 ◽  
Author(s):  
John L. Sexton ◽  
Harvey Henson Jr.

The interpretation of 1047 km of seismic reflection data collected in western Lake Superior is presented along with reflection traveltime contour maps and gravity models to understand the overall geometry of the Midcontinent Rift System beneath the lake. The Douglas, Isle Royale, and Keweenaw fault zones, clearly imaged on the seismic profiles, are interpreted to be large offset detachment faults associated with initial rifting. These faults have been reactivated as reverse faults with 3–5 km of throw. The Douglas Fault Zone is not directly connected with the Isle Royale Fault Zone. The seismic data has imaged two large basins filled with more than 22 km of middle Keweenawan pre-Portage Lake and Portage Lake volcanic rocks and up to 8 km of upper Keweenawan Oronto and Bayfield sedimentary rocks. These basins persisted throughout Keweenawan time and are separated by a ridge of Archean rocks and a narrow trough bounded by the Keweenaw Fault Zone to the south. Another fault zone, herein named the Ojibwa fault zone, previously interpreted as the northeastern extension of the Douglas Fault Zone, has been reinterpreted as a reverse fault that closely follows the ridge of Archean rocks. Previous researchers have stated that neighboring segments of the rift display alternating polarity of basins associated with large detachment faults. Accommodation zones have been previously interpreted to exist between rift segments; however, the seismic data do not image a clearly identifiable accommodation zone separating the two basins in western Lake Superior. Thus, the seismic profile may lie directly above the pivot of a scissors-type accommodation fault zone, there is no vertical offset associated with the zone, or the zone does not exist. Seismic data interpretations indicate that application of a simple alternating polarity basin – accommodation zone model is an oversimplification of the complex geological structures associated with the Midcontinent Rift System.


2017 ◽  
Vol 43 (1) ◽  
pp. 357 ◽  
Author(s):  
J. Papoulia ◽  
J. Makris

We developed velocity models of the crust and sediments offshore south western Greece, between the island of Zakynthos and Messinia. Using these velocity models and depth migrating the seismic data we delineated the main faults and associated them with the tectonic processes of western Greece. This active seismic experiment was essential for defining the limits between the continental domain of western Greece and the oceanic one of the deep Ionian Sea. We successfully linked the onshore with the offshore tectonics and for the first time it was possible to understand how the main dextral fault systems of Cephalonia and Andravida are responsible for the crustal deformation, and its link to the local seismicity. Most of the seismic activity is connected to thrusting, due to crustal shortening or strike-slip faulting that follows the two main dextral wrench faults of Cephalonia and Andravida. It was recognized that the back stop offshore western Peloponnese is floored by thinned continental crust of Preapulia and that the Hellenic Alpine napes do not extend in the back stop domain.


1991 ◽  
Vol 18 (4) ◽  
pp. 625-628 ◽  
Author(s):  
A. Tréhu ◽  
P. Morel-à-l'Huissier ◽  
R. Meyer ◽  
Z. Hajnal ◽  
J. Karl ◽  
...  

Geophysics ◽  
2017 ◽  
Vol 82 (4) ◽  
pp. V201-V209 ◽  
Author(s):  
David Harris ◽  
Julie Albaric ◽  
Bettina Goertz-Allmann ◽  
Daniela Kuehn ◽  
Sebastian Sikora ◽  
...  

Mechanical and electromagnetic interference (process noise) is common in seismic data recorded to monitor and characterize induced microseismicity during industrial injection and production operations. We have developed a case study of adaptive cancellation to reduce observed process noise in passive seismic data recorded during the 2014 injection test at the [Formula: see text] Lab research site in Spitsbergen. Our results suggest that adaptive cancellation is effective when major sources of interference are readily identifiable. Adaptive cancellation requires these sources to be instrumented separately but conceivably with low-cost sensors. We suggest that adaptive cancellation should be considered routinely when planning microseismic monitoring operations when strong industrial or anthropogenic noise is anticipated. Interference suppression algorithms are sufficiently simple that they could be implemented in acquisition systems to avoid archival of noise reference data.


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