scholarly journals A shallow seismic survey, elastic constants studies and surficial geology of part of Defence Research Establishment Suffield, Alberta

1970 ◽  
Author(s):  
G D Hobson ◽  
J A M Hunter ◽  
J S Scott
Keyword(s):  
Elastic Constants ◽  
Seismic Survey ◽  
Surficial Geology ◽  
Shallow Seismic ◽  
Defence Research

Improving surface‐wave group velocity measurements by energy reassignment

Geophysics ◽  
2003 ◽  
Vol 68 (2) ◽  
pp. 677-684 ◽  
Author(s):  
Helle A. Pedersen ◽  
Jérôme I. Mars ◽  
Pierre‐Olivier Amblard
Keyword(s):  
Surface Waves ◽  
Dispersion Curve ◽  
Group Velocity ◽  
Shear Wave ◽  
Group Velocity Dispersion ◽  
Seismic Survey ◽  
Earth Model ◽  
Velocity Measurements ◽  
Time Frequency ◽  
Shallow Seismic

Surface waves are increasingly used for shallow seismic surveys—in particular, in acoustic logging, environmental, and engineering applications. These waves are dispersive, and their dispersion curves are used to obtain shear velocity profiles with depth. The main obstacle to their more widespread use is the complexity of the associated data processing and interpretation of the results. Our objective is to show that energy reassignment in the time–frequency domain helps improve the precision of group velocity measurements of surface waves. To show this, full‐waveform seismograms with added white noise for a shallow flat‐layered earth model are analyzed by classic and reassigned multiple filter analysis (MFA). Classic MFA gives the expected smeared image of the group velocity dispersion curve, while the reassigned curve gives a very well‐constrained, narrow dispersion curve. Systematic errors from spectral fall‐off are largely corrected by the reassignment procedure. The subsequent inversion of the dispersion curve to obtain the shear‐wave velocity with depth is carried out through a procedure combining linearized inversion with a nonlinear Monte Carlo inversion. The diminished uncertainty obtained after reassignment introduces significantly better constraints on the earth model than by inverting the output of classic MFA. The reassignment is finally carried out on data from a shallow seismic survey in northern Belgium, with the aim of determining the shear‐wave velocities for seismic risk assessment. The reassignment is very stable in this case as well. The use of reassignment can make dispersion measurements highly automated, thereby facilitating the use of surface waves for shallow surveys.

Seismic investigations offshore South-East Greenland

1998 ◽  
pp. 145-151
Author(s):  
John R. Hopper ◽  
Dan Lizarralde ◽  
Hans Christian Larsen
Keyword(s):  
North Atlantic ◽  
Tectonic Evolution ◽  
Seismic Survey ◽  
East Greenland ◽  
The North ◽  
Shallow Seismic ◽  
Site Survey ◽  
Drilling Operations ◽  
Greenland Margin ◽  
Cooperative Venture

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Hopper, J. R., Lizarralde, D., & Larsen, H. C. (1998). Seismic investigations offshore South-East Greenland. Geology of Greenland Survey Bulletin, 180, 145-151. https://doi.org/10.34194/ggub.v180.5098 _______________ A high-resolution, shallow-seismic survey off the SouthEast Greenland coast was carried out during August and September 1997 aboard the R/V Dana of the Danish Ministry of Agriculture and Fisheries. This seismic survey supports two large ongoing regional research projects. The Danish Lithosphere Centre (DLC) is involved in a number of investigations to understand the tectonic evolution of the North Atlantic region since the early Tertiary, and a consortium of scientists from the Geological Survey of Denmark and Greenland (GEUS) and the Free University of Amsterdam (VU) are engaged in palaeo-oceanographic studies of climate change since the Neogene. The survey was thus a cooperative venture where ship time was shared between the participating research institutes. This report focuses on the DLC component of the cruise, which primarily involved the acquisition of site-survey data to be used in the planning and execution of drilling operations scheduled for 1998. These drilling operations are aimed at understanding the voluminous volcanic activity that accompanied continental rifting and the formation of the South-East Greenland margin. The GEUS/VU component of the cruise is summarised elsewhere in this volume (Kuijpers et al. 1998, this volume).

scholarly journals Offshore Gunung Jerai shallow seismic survey

1982 ◽  
Vol 15 ◽  
pp. 71-82 ◽  
Author(s):  
G. van Klinken ◽  
◽  
Q.A. Halim
Keyword(s):  
Seismic Survey ◽  
Shallow Seismic
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