Mapping shallow faults at the Evrona playa site using high‐resolution reflection method

Geophysics ◽  
1998 ◽  
Vol 63 (4) ◽  
pp. 1257-1264 ◽  
Author(s):  
Vladimir Shtivelman ◽  
Uri Frieslander ◽  
Ezra Zilberman ◽  
Rivka Amit
Keyword(s):  
High Resolution ◽  
Seismic Energy ◽  
Morphological Features ◽  
Geological Mapping ◽  
P Wave ◽  
Aerial Photographs ◽  
Seismic Survey ◽  
Good Correspondence ◽  
Reflection Data ◽  
Seismic Sections

A shallow high‐resolution seismic reflection survey was carried out at the Evrona playa site in the southern Arava valley, Israel. The aim of the survey was to detect and map faults in the shallow subsurface (upper 100–150 m) and establish the relationship of the morphological features revealed by aerial photographs and surface geological mapping with the faults detected in the subsurface. The survey included three seismic lines shot using the P-wave technique and one SH-wave line, which overlapped one of the P-wave lines. The seismic energy source on all the lines was a sledge hammer. The acquired reflection data were of good quality and did not require special processing efforts. The seismic sections along the lines show a sequence of reflected events within the 8–150 m range. At several locations, continuity of the events is interrupted by a system of faults. These faults form flower structures apparently related to strike‐slip motions typical of the region. Comparison of the faults mapped on the seismic sections with those expressed by surface morphological features generally show good correspondence. The results of the seismic survey provide important information for the study of paleoseismicity and seismic hazards in the investigated area.

Structural interpretation using refraction velocities from marine seismic surveys

Geophysics ◽  
1986 ◽  
Vol 51 (1) ◽  
pp. 12-19 ◽  
Author(s):  
James F. Mitchell ◽  
Richard J. Bolander
Keyword(s):  
Sedimentary Rock ◽  
Seismic Energy ◽  
Seismic Survey ◽  
Subsurface Structure ◽  
Seismic Reflection Data ◽  
Near Surface ◽  
Reflection Data ◽  
Wide Range ◽  
Streamer Length ◽  
Set Up

Subsurface structure can be mapped using refraction information from marine multichannel seismic data. The method uses velocities and thicknesses of shallow sedimentary rock layers computed from refraction first arrivals recorded along the streamer. A two‐step exploration scheme is described which can be set up on a personal computer and used routinely in any office. It is straightforward and requires only a basic understanding of refraction principles. Two case histories from offshore Peru exploration demonstrate the scheme. The basic scheme is: step (1) shallow sedimentary rock velocities are computed and mapped over an area. Step (2) structure is interpreted from the contoured velocity patterns. Structural highs, for instance, exhibit relatively high velocities, “retained” by buried, compacted, sedimentary rocks that are uplifted to the near‐surface. This method requires that subsurface structure be relatively shallow because the refracted waves probe to depths of one hundred to over one thousand meters, depending upon the seismic energy source, streamer length, and the subsurface velocity distribution. With this one requirement met, we used the refraction method over a wide range of sedimentary rock velocities, water depths, and seismic survey types. The method is particularly valuable because it works well in areas with poor seismic reflection data.

Volcanoes geological mapping and structural geology with UAS High Resolution Digital Terrain Model : the Kuei-Shan Tao case example (Eastern Taiwan).

2021 ◽  
Author(s):  
Benoit Deffontaines ◽  
Kuo-Jen Chang ◽  
Samuel Magalhaes ◽  
Gérardo Fortunato
Keyword(s):  
High Resolution ◽  
Okinawa Trough ◽  
Volcanic Rocks ◽  
Digital Terrain Model ◽  
Structural Features ◽  
Point Of View ◽  
Geological Mapping ◽  
Lava Flows ◽  
Aerial Photographs ◽  
Structural Scheme

<p>Volcanic areas in the World are often difficult to map especially in a structural point of view as (1) fault planes are generally covered and filled by more recent lava flows and (2) volcanic rocks have very few tectonic striations. Kuei-Shan Tao (11km from Ilan Plain – NE Taiwan) is a volcanic island, located at the soutwestern tip of the South Okinawa trough (SWOT). Two incompatible geological maps had been already published both lacking faults and structural features (Hsu, 1963 and Chiu et al., 2010). We propose herein not only to up-date the Kuei-Shan Tao geological map with our high resolution dataset, but also to create the Kuei-Shan Tao structural scheme in order to better understand its geological and tectonic history.</p><p>Consequently, we first acquired aerial photographs from our UAS survey and get our new UAS high resolution DTM (HR UAS-DTM hereafter) with a ground resolution <10cm processed through classical photogrammetric methods. Taking into account common sense geomorphic and structural interpretation and reasoning deduced form our HR UAS-DTM, and the outcropping lithologies situated all along the shoreline, we have up-dated the Kuei-Shan Tao geological mapping and its major structures. To conclude, the lithologies (andesitic lava flows and pyroclastic falls) and the new structural scheme lead us to propose a scenario for both the construction as well as the dismantling of Kuei-Shan Tao which are keys for both geology and geodynamics of the SWOT.</p>

Shallow seismic investigation of a site with poor reflection quality

Geophysics ◽  
1995 ◽  
Vol 60 (6) ◽  
pp. 1715-1726 ◽  
Author(s):  
Yih Jeng
Keyword(s):  
Seismic Energy ◽  
Dominant Frequency ◽  
P Wave ◽  
Sh Wave ◽  
P Waves ◽  
Frequency Bands ◽  
Energy Field ◽  
Reflection Data ◽  
Shallow Seismic ◽  
A Site

A shallow seismic reflection experiment was performed on a construction site to determine the feasibility of using reflection seismology to investigate the shallow structure in a weathered sand‐gravel interlayered zone that was known to be a poor transmission of high‐frequency seismic energy. Field‐recording parameters were designed to fit the limited space of the urban construction survey area. A 7 kg sledgehammer was used to generate P‐waves and SH‐waves. Single 100 Hz geophones were deployed at 1.0 m/0.5 m group intervals, and 200/100-Hz low‐cut filters were applied prior to A to D conversion to attenuate ground roll. For SH‐wave reflections, single 14 Hz geophones and a 70-Hz low‐cut filter on the seismograph were used. The dominant frequency bands ranged from 33 to 275 Hz and were centered around 110 Hz for P‐waves. Lower dominant frequency bands 20 to 160 Hz with a dominant frequency of around 85 Hz were observed on SH‐wave records. Four seismic lines, three P‐wave recordings and one SH‐wave recording, using different sets of recording parameters and an appropriate seismic‐wave generation method produced reflections from varying depth ranges and at different resolutions. The results show that the techniques employed in this experiment may resolve the structure of a site with poor reflection quality. An f-k dip filtering and deconvolution were necessary in processing the reflection data to eliminate various types of unwanted energy. The seismic interpretations in this study were verified by drilling and by a nearby excavation.

Locating faults in underground coal mines using high‐resolution seismic reflection techniques

Geophysics ◽  
1989 ◽  
Vol 54 (12) ◽  
pp. 1521-1527 ◽  
Author(s):  
Lawrence M. Gochioco ◽  
Steven A. Cotten
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Seismic Reflection ◽  
Coal Mines ◽  
Seismic Source ◽  
Seismic Survey ◽  
Underground Coal Mines ◽  
Vertical Displacements ◽  
Seismic Sections ◽  
Mine Development

A high‐resolution seismic reflection technique was used to locate faults in coal seams that were not visible on the surface and could only be observed in underground coal mines. An 8‐gauge buffalo gun, built by the research and development department of Consolidation Coal Company, was used as the seismic source. The coal seam at a depth of 700 ft produces a reflection with a predominant frequency of about 125 Hz. The high‐resolution seismic data permitted faults with vertical displacements of the same magnitude as the seam thickness to be detected at depths of several hundred feet beneath the surface. Several faults were detected and interpreted from the seismic sections, and the magnitudes of their displacement were estimated by matching the recorded seismic data to synthetic seismic data. Subsequent underground mine development in the study area confirmed two interpreted faults and their estimated displacements. Mining engineers were able to use the information provided by the seismic survey to plan an entry system through the fault zone so that less rock needed to be mined, resulting in a safer and more productive mine.

scholarly journals Broadband Q-Factor Imaging for Geofluid Detection in the Gulf of Trieste (Northern Adriatic Sea)

2021 ◽  
Vol 9 ◽  
Author(s):  
Aldo Vesnaver ◽  
Gualtiero Böhm ◽  
Martina Busetti ◽  
Michela Dal Cin ◽  
Fabrizio Zgur
Keyword(s):  
Adriatic Sea ◽  
Seismic Energy ◽  
P Wave ◽  
Seismic Survey ◽  
Gas Reservoirs ◽  
Northern Adriatic Sea ◽  
Seismic Attribute ◽  
Northern Adriatic ◽  
Gulf Of Trieste ◽  
Impedance Contrast

Seismic surveys allow estimating lithological parameters, as P-wave velocity and anelastic absorption, which can detect the presence of fracture and fluids in the geological formations. Recently, a new method has been proposed for high-resolution imaging of anelastic absorption, which combines a macro-model from seismic tomography with a micro-model obtained by the pre-stack depth migration of a seismic attribute, i.e., the instantaneous frequency. As a result, we can get a broadband image that provides clues about the presence of saturating fluids. When the saturation changes sharply, as for gas reservoirs with an impermeable caprock, the acoustic impedance contrast produces “bright spots” because of the resulting high reflectivity at its top. When the fluid content changes smoothly, the anelastic absorption becomes a good detector, as fluid-filled formations absorb more seismic energy than hard rocks. We apply this method for imaging the anelastic absorption in a regional seismic survey acquired by OGS in the Gulf of Trieste (northern Adriatic Sea, Italy).

Improved imaging of the Strzelecki Formation by the reprocessing of 3D seismic reflection data: onshore Gippsland Basin, Australia

2015 ◽  
Vol 55 (2) ◽  
pp. 465
Author(s):  
Hadi Nourollah ◽  
Javad Aliemrani
Keyword(s):  
Seismic Energy ◽  
Velocity Model ◽  
Seismic Survey ◽  
3D Seismic ◽  
Seismic Section ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Novel Approach ◽  
Original Survey ◽  
And Migration

The Wombat 3D seismic survey was recorded by Lakes Oil in 2008 following the drilling of the Wombat–3 well. The survey was aimed at identifying the structures better inside the Strzelecki Formation and the underlying Rintoul Creek Sandstone, and to give a better understanding of the provenance of the gas encountered in the first three Wombat wells and the oil encountered at depth in the Wombat–3 well. Seismic acquisition design and processing in this area are challenged by the presence of coal measures in the Latrobe Group, which overlies the zone of interest, absorbs most of the incident seismic energy and complicates seismic imaging through the generation of multiple reflection events. A novel approach, described as multi-line decomposition, modelling and synthesis, was developed to model critical imaging parameters and in particular the velocity model for midpoint stacking and migration. This approach is demonstrated through the reprocessing of the Wombat 3D seismic survey and is compared with a conventional 3D processing approach and original survey processing examples. The reprocessed seismic section provides a significantly improved image of the deeper structures, delineating a number of continuous reflectors in the Early Cretaceous formations. It also provides the opportunity to build a more accurate model of the basement.

Near‐surface seismic reflection profiling of the Matanuska Glacier, Alaska

Geophysics ◽  
2003 ◽  
Vol 68 (1) ◽  
pp. 147-156 ◽  
Author(s):  
Gregory S. Baker ◽  
Jeffrey C. Strasser ◽  
Edward B. Evenson ◽  
Daniel E. Lawson ◽  
Kendra Pyke ◽  
...  
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Longitudinal Axis ◽  
Horizontal Distribution ◽  
P Wave ◽  
Near Surface ◽  
Surface Reflection ◽  
Reflection Data ◽  
Basal Ice ◽  
Matanuska Glacier

Several common‐midpoint seismic reflection profiles collected on the Matanuska Glacier, Alaska, clearly demonstrate the feasibility of collecting high‐quality, high‐resolution near‐surface reflection data on a temperate glacier. The results indicate that high‐resolution seismic reflection can be used to accurately determine the thickness and horizontal distribution of debris‐rich ice at the base of the glacier. The basal ice thickens about 30% over a 300‐m distance as the glacier flows out of an overdeepening. The reflection events ranged from 80‐ to 140‐m depth along the longitudinal axis of the glacier. The dominant reflection is from the contact between clean, englacial ice and the underlying debris‐rich basal ice, but a strong characteristic reflection is also observed from the base of the debris‐rich ice (bottom of the glacier). The P‐wave propagation velocity at the surface and throughout the englacial ice is 3600 m/s, and the frequency content of the reflections is in excess of 800 Hz. Supporting drilling data indicate that depth estimates are correct to within ± 1 m.

Ultra-High-Resolution 3D (UHR3D) Seismic Survey - Application to Hinagu Fault Zone, Yatsushiro Sea, Kyushu, Japan -

2018 ◽  
Vol 71 (0) ◽  
pp. 33-42
Author(s):  
Shigeru Ino ◽  
Shigeyuki Suda ◽  
Hidekuni Kikuchi ◽  
Shiro Ohkawa ◽  
Shintaro Abe ◽  
...  
Keyword(s):  
High Resolution ◽  
Fault Zone ◽  
Seismic Survey ◽  
Yatsushiro Sea
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