scholarly journals Plio-Pleistocene fault pattern of the Feldbiss fault system (southern border of the Roer Valley Graben, Belgium) based on high resolution reflection seismic data

2001 ◽  
Vol 80 (3-4) ◽  
pp. 79-93 ◽  
Author(s):  
M. Dusar ◽  
J. Rijpens ◽  
M. Sintubin ◽  
L. Wouters
Keyword(s):  
High Resolution ◽  
Seismic Survey ◽  
Fault System ◽  
Tectonic Activity ◽  
Depth Range ◽  
Near Surface ◽  
Reflection Seismic ◽  
Lower Pleistocene ◽  
Roer Valley Graben ◽  
Southern Border

AbstractA high-resolution reflection seismic survey was carried out in 1999 over the Feldbiss fault system, the southern border of the Roer Valley graben, in Belgium. Six profile-lines with total length of 13982 m provided information on the 40-600 m depth range, covering Lower Pleistocene to Miocene strata with special emphasis on the Plio-Pleistocene Kieseloolite formation. Data quality depends on near-surface conditions and on degree of deformation in some fault zones, with better results for seismic detonator sources compared to vibroseis sources. The new data confirm the segmented character of the fault system with occurrence of fault bends, relay ramps and branching of overlapping fault sequences, testifying of the strong tectonic activity during the lower Pleistocene. Antiform structures along the Bichterweerd scarp, relaying the Feldbiss to the Geleen fault in the Meuse valley, are presented as a model for the Tertiary evolution of the Bree Uplift.

The use of geophysical prospecting for imaging active faults in the Roer Graben, Belgium

Geophysics ◽  
2001 ◽  
Vol 66 (1) ◽  
pp. 78-89 ◽  
Author(s):  
Donat Demanet ◽  
François Renardy ◽  
Kris Vanneste ◽  
Denis Jongmans ◽  
Thierry Camelbeeck ◽  
...  
Keyword(s):  
High Resolution ◽  
Physical Properties ◽  
Fault Zone ◽  
Geophysical Methods ◽  
Depth Range ◽  
Electrical Tomography ◽  
Reflection Seismic ◽  
Refraction Seismic ◽  
Geophysical Surveys ◽  
Geophysical Techniques

As part of a paleoseismological investigation along the Bree fault scarp (western border of the Roer Graben), various geophysical methods [electrical profiling, electromagnetic (EM) profiling, refraction seismic tests, electrical tomography, ground‐penetrating radar (GPR), and high‐resolution reflection seismic profiles] were used to locate and image an active fault zone in a depth range between a few decimeters to a few tens of meters. These geophysical investigations, in parallel with geomorphological and geological analyses, helped in the decision to locate trench excavations exposing the fault surfaces. The results could then be checked with the observations in four trenches excavated across the scarp. Geophysical methods pointed out anomalies at all sites of the fault position. The contrast of physical properties (electrical resistivity and permittivity, seismic velocity) observed between the two fault blocks is a result of a differences in the lithology of the juxtaposed soil layers and of a change in the water table depth across the fault. Extremely fast techniques like electrical and EM profiling or seismic refraction profiles localized the fault position within an accuracy of a few meters. In a second step, more detailed methods (electrical tomography and GPR) more precisely imaged the fault zone and revealed some structures that were observed in the trenches. Finally, one high‐resolution reflection seismic profile imaged the displacement of the fault at depths as large as 120 m and filled the gap between classical seismic reflection profiles and the shallow geophysical techniques. Like all geophysical surveys, the quality of the data is strongly dependent on the geologic environment and on the contrast of the physical properties between the juxtaposed formations. The combined use of various geophysical techniques is thus recommended for fault mapping, particularly for a preliminary investigation when the geological context is poorly defined.

Reflection seismic imaging of buried shallow salt structures – examples from ongoing case studies in Northern Germany

2021 ◽  
Author(s):  
Ulrich Polom ◽  
Rebekka Mecking ◽  
Phillip Leineweber ◽  
Andreas Omlin
Keyword(s):  
High Resolution ◽  
Water Resources ◽  
Industrial Development ◽  
Geophysical Methods ◽  
Hydrocarbon Exploration ◽  
P Wave ◽  
Depth Range ◽  
Reflection Seismic ◽  
Wide Range ◽  
Cap Rock

<p>In the North German Basin salt tectonics generated a wide range of evaporite structures since the Upper Triassic, resulting in e.g. extended salt walls, salt diapirs, and salt pillows in the depth range up to 8 km. Due to their trap and seal properties these structures were in the focus of hydrocarbon exploration over many decades, leading to an excellent mapping of their geometries below 300 m in depth. During salt rise Rotliegend formations were partly involved as a constituent. Some structures penetrated the salt table, some also the former surface. Dissolution (subrosion) and erosion of the salt cap rock by meteoric water took place, combined with several glacial and intraglacial overprints. Finally the salt structures were covered by pleistocene and holocene sediments. This situation partly resulted in proneness for ongoing karstification of the salt cap rock, leading to e.g. local subsidence and sinkhole occurrence at the surface. The geometry, structure and internal lithology of these shallow salt cap rocks are widely unknown. Expanding urban and industrial development, water resources management and increasing climate change effects enhance the demands for shallow mapping and characterization of these structures regarding save building grounds and sustainable water resources.</p><p>Results of shallow drilling investigations of the salt cap rock and the overburden show unexpectedly heterogenous subsurface conditions, yielding to limited success towards mapping and characterization. Thus, shallow high-resolution geophysical methods are in demand to close the gaps with preferred focus of applicability in urban and industrial environments. Method evaluations starting in 2010 geared towards shallow high-resolution reflection seismic to meet the requirements of both depth penetration and structure resolution. Since 2017 a combination of S-wave and P-wave seismic methods including depth calibrations by Vertical Seismic Profiling (VSP) enabled 2.5D subsurface imaging starting few meters below the surface up to several hundred meters depth in 0.5-5 m resolution range, respectively. The resulting profiles image strong variations along the boundaries and on top of the salt cap rock. Beside improved mapping capabilities, aim of research is the development of characteristic data features to differentiate save and non-save areas.</p>

3D seismic traveltime tomography imaging of the shallow subsurface at the C O2 SINK project site, Ketzin, Germany

Geophysics ◽  
2009 ◽  
Vol 74 (1) ◽  
pp. G1-G15 ◽  
Author(s):  
Sawasdee Yordkayhun ◽  
Ari Tryggvason ◽  
Ben Norden ◽  
Christopher Juhlin ◽  
Björn Bergman
Keyword(s):  
Velocity Structure ◽  
Velocity Model ◽  
Geological Structure ◽  
Seismic Survey ◽  
Storage Site ◽  
Near Surface ◽  
Shallow Subsurface ◽  
Traveltime Tomography ◽  
Reflection Seismic ◽  
Reflection Data

A 3D reflection seismic survey was performed in 2005 at the Ketzin carbon dioxide [Formula: see text] pilot geological-storage site (the [Formula: see text] project) near Berlin, Germany, to image the geological structure of the site to depths of about [Formula: see text]. Because of the acquisition geometry, frequency limitations of the source, and artefacts of the data processing, detailed structures shallower than about [Formula: see text] were unclear. To obtain structural images of the shallow subsurface, we applied 3D traveltime tomography to data near the top of the Ketzin anticline, where faulting is present. Understanding the shallow subsurface structure is important for long-term monitoring aspects of the project after [Formula: see text] has been injected into a saline aquifer at about [Formula: see text] depth. We used a 3D traveltime tomography algorithm based on a combination ofsolving for 3D velocity structure and static corrections in the inversion process to account for artefacts in the velocity structure because of smearing effects from the unconsolidated cover. The resulting velocity model shows low velocities of [Formula: see text] in the uppermost shallow subsurface of the study area. The velocity reaches about [Formula: see text] at a depth of [Formula: see text]. This coincides approximately with the boundary between Quaternary units, which contain the near-surface freshwater reservoir and the Tertiary clay aquitard. Correlation of tomographic images with a similarity attribute slice at [Formula: see text] (about [Formula: see text] depth) indicates that at least one east-west striking fault zone observed in the reflection data might extend into the Tertiary unit. The more detailed images of the shallow subsurface from this study provided valuable information on this potentially risky area.

Repeated megaturbidite deposition in Lake Crescent, Washington, USA, triggered by Holocene ruptures of the Lake Creek-Boundary Creek fault system

2019 ◽  
Vol 131 (11-12) ◽  
pp. 2039-2055 ◽  
Author(s):  
Elana L. Leithold ◽  
Karl W. Wegmann ◽  
Delwayne R. Bohnenstiehl ◽  
Catelyn N. Joyner ◽  
Audrianna F. Pollen
Keyword(s):  
Critical Infrastructure ◽  
Fault Scarp ◽  
Seismic Survey ◽  
Fault System ◽  
Olympic Peninsula ◽  
Reflection Seismic ◽  
The North ◽  
Dextral Shear ◽  
Western Washington ◽  
Late Pleistocene To Holocene

Abstract Lake Crescent, a 180-m-deep, glacially carved lake located on the Olympic Peninsula in western Washington, USA, overlies the Lake Creek-Boundary Creek fault zone, a system of structures with at least 56 km of late Pleistocene to Holocene surface rupture. Investigation of the lake’s sediment, including a reflection seismic survey and analysis of piston cores, reveals evidence that the fault beneath the lake has ruptured four times in the past ∼7200 years, producing unusually thick deposits termed megaturbidites. The earthquakes triggered rockslides that entered the lake and caused displacement waves (lake tsunamis) and seiches, most recently ca. 3.1 ka. Seismic reflection results from beneath the depth of core penetration reveal at least two older post-glacial ruptures that are likely to have similarly affected the lake. The stratigraphy of Lake Crescent provides insight into the behavior of a fault system that partially accommodates regional clockwise rotation and contraction of the northern Cascadia forearc through oblique dextral shear, and highlights the potential for disruption to critical infrastructure, transportation corridors, and industry on the North Olympic Peninsula during future surface-rupturing earthquakes. Our results illustrate the potential synergism between lacustrine paleoseismology and fault-scarp trench investigations. More precise dating of strong earthquake shaking afforded by continuous accumulation of lake sediment improves earthquake histories based on trenched fault scarp exposures, which are commonly poorly dated.

STRUCTURAL EVOLUTION OF THE CARNARVON TERRACE, WESTERN AUSTRALIA

1995 ◽  
Vol 35 (1) ◽  
pp. 321 ◽  
Author(s):  
P.W. Baillie ◽  
E. Jacobson
Keyword(s):  
High Resolution ◽  
Western Australia ◽  
Long Island ◽  
Structural Evolution ◽  
Early Jurassic ◽  
Seismic Survey ◽  
Fault System ◽  
Late Triassic ◽  
Structural Configuration ◽  
Break Up

The under-explored Carnarvon Terrace is situated offshore of the Cape Range area in the Carnarvon Basin near the boundary of the Gascoyne and Exmouth Sub-basins. The stratigraphy of the area is controlled by only two wells (Pendock-1, Yardie East-1), but several onshore wells aid interpretation of seismic data.Understanding of the structural evolution of the region is facilitated by interpretation of a high-resolution non-exclusive seismic survey acquired by Geco-Prakla in 1993 (GPCTR-93 Survey).Three major tectonic stages are responsible for the structural configuration of the region:Late Palaeozoic extension in the Gascoyne Sub-basin;continental break-up between Australia and Greater India which took place along a major fracture marked by the Flinders-Long Island-Learmonth fault system active in Late Triassic and Early Jurassic times; andthe collision between Australia and Asia that commenced in Miocene times and is continuing to the present day. This event, marked by wrench and compressional structures, and often reactivation of older structures, is one of the most economically important in Australian geological history.From a regional prospectivity viewpoint at least three plays are worthy of further investigation.

Analysing landforms, borehole logs, and geophysics, for localization and assessment of active faults in the central Vienna Basin (Austria)

2020 ◽  
Author(s):  
Michael Weissl ◽  
Decker Kurt ◽  
Adrian Flores-Orozco ◽  
Matthias Steiner
Keyword(s):  
Active Faults ◽  
Fault System ◽  
Tectonic Activity ◽  
Fluvial Sediments ◽  
River Channels ◽  
Vienna Basin ◽  
Geothermal Resources ◽  
Near Surface ◽  
Growth Strata ◽  
Fault Scarps

<p>The formation of pull apart basins and normal faulting at splays along the Vienna Basin strike-slip fault system resulted in the dissection of the Pleistocene river terraces of the Danube. Displacements of terrace segments are visible on the surface as fault scarps or dells what allows mapping the system of active faults. Furthermore displacement rates can be estimated from the elevation of the basis and the thickness of Quaternary fluvial sediments.</p><p>With regard to the prospective utilization of geothermal resources in the area of Vienna a research group was built (Geotief Explore 3D, funded by Wien Energie and FFG) with the objective to identify, map, and assess, Quaternary faults, because such rupture zones are not suitable for the reinjection of thermal water in view of the hazard of triggered earthquakes.</p><p>Normal splay faults define the eastern and western margins of Pleistocene Danube terraces north of Vienna. The bodies of these terraces are built up of coarse sandy gravel and sand whereas their surfaces are covered with aeolian and alluvial sediments of the last glacial. Tectonic displacements during the Pleistocene left distinct marks in the late glacial landform configuration of the terraces. Therefore many fault scarps and fault related valleys are clearly cognizable in high resolution LiDAR and satellite images.</p><p>During the last decade three distinct fault scarps of the Vienna Basin Transform Fault situated at the terrace edges could be investigated by trenching and transect analysis. Actual research has the objective to model the 3D geometry of the base of the Quaternary strata (horizon Base Quaternary) from a compilation of shallow drillings and the construction of a regional isopach map showing the thickness of Quaternary (growth-) strata.</p><p>In the course of research it becomes apparent that within the tectonically subsided areas evidence of neotectonics is overprinted by fluvial sediments and alluvium what hinders accurate localization of faults. However, the sinuosity of palaeochannels in the Danube floodplain seems to be related to tectonics and therefore the pattern of former river channels can be used as sign for tectonic activity during the Pleistocene. In places where signs for active faulting are completely overprinted by fluvial sedimentation and cryoturbation the approved methods for the localization and the assessment of active faults are electrical resistivity tomography and near-surface seismics.</p>

High‐resolution seismic traveltime tomography incorporating static corrections applied to a till‐covered bedrock environment

Geophysics ◽  
2004 ◽  
Vol 69 (4) ◽  
pp. 1082-1090 ◽  
Author(s):  
Björn Bergman ◽  
Ari Tryggvason ◽  
Christopher Juhlin
Keyword(s):  
High Resolution ◽  
Velocity Model ◽  
Surface Velocity ◽  
Data Set ◽  
Near Surface ◽  
Seismic Processing ◽  
Simultaneous Inversion ◽  
Reflection Seismic ◽  
Static Corrections ◽  
Velocity Variations

A major obstacle in tomographic inversion is near‐surface velocity variations. Such shallow velocity variations need to be known and correctly accounted for to obtain images of deeper structures with high resolution and quality. Bedrock cover in many areas consists of unconsolidated sediments and glacial till. To handle the problems associated with this cover, we present a tomographic method that solves for the 3D velocity structure and receiver static corrections simultaneously. We test the method on first‐arrival picks from deep seismic reflection data acquired in the mid‐ late to 1980s in the Siljan Ring area, central Sweden. To use this data set successfully, one needs to handle a number of problems, including time‐varying, near‐surface velocities from data recorded in winter and summer, several sources and receivers within each inversion cell, varying thickness of the cover layer in each inversion cell, and complex 3D geology. Simultaneous inversion for static corrections and velocity produces a much better image than standard tomography without statics. The velocity model from the simultaneous inversion is superior to the velocity model produced using refraction statics obtained from standard reflection seismic processing prior to inversion. Best results using the simultaneous inversion are obtained when the initial top velocity layer is set to the near‐surface bedrock velocity rather than the velocity of the cover. The resulting static calculations may, in the future, be compared to refraction static corrections in standard reflection seismic processing. The preferred final model shows a good correlation with the mapped geology and the airborne magneticmap.

scholarly journals Manifestations of deep degasing into the water column and upper part of the Pechora sea sedimentary section

Georesursy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 68-76
Author(s):  
Sergey Yu. Sokolov ◽  
Evgeniy A. Moroz ◽  
Elena A. Sukhikh ◽  
Anatoliy A. Razumovskiy ◽  
Oleg V. Levchenko
Keyword(s):  
Water Column ◽  
Survey Data ◽  
Seismic Survey ◽  
Tectonic Activity ◽  
Bright Spot ◽  
Near Surface ◽  
Free Gas ◽  
Russian Academy Of Sciences ◽  
Quaternary Sequences ◽  
Academy Of Sciences

Studies of acoustic anomalies in the water column and seismoacoustic anomalies in the Quaternary sediments of Pechora sea and their relationship with deep hydrocarbon sources were conducted by the Institute of Oceanology of the Russian Academy of Sciences and the Geological Institute of the Russian Academy of Sciences in the 38th cruise of RV “Academik Nikolaj Strakhov” in 2018. Mapping of free gas manifestations presents an additional indicator of tectonic activity and the fault network frame, which provides the flow of fluids from deep horizons. Comparison of high-resolution seismic survey data with deep seismic survey data shows that the fluid in the upper part of the section is first accumulated under the bottom of Jurassic-Cretaceous sedimentary sequences, which are fluid-resistant. Local dislocations of fluid trap lead to further rise and redistribution of free gas in Quaternary sequences. Natural or artificial break of their integrity results in the release of gas into the water column from near-surface accumulations that were found in the form of “bright spot” anomalies on seismic-acoustic records. Mapping of sound scattering objects in the water column shows the degassing areas, which are usually located above the deep faults. “Bright spots” of free gas in the Quaternary sequences have a variety of shapes – multi-tiered and inclined. Gas breaks into the water column occur near the edges of these anomalies. Systematic mapping of the considered phenomena is a necessary element in the preparation of the area for industrial operation.

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