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>

Delineating active faults across the Narmada-Son Lineament (NSL), India using the technique of Fracture Induced Electromagnetic Radiation (FEMR)

2021 ◽  
Author(s):  
Shreeja Das ◽  
Jyotirmoy Mallik
Keyword(s):  
Electromagnetic Radiation ◽  
Process Zone ◽  
Active Faults ◽  
Central India ◽  
Earthquake Forecasting ◽  
Tectonic Activity ◽  
Eurasian Plate ◽  
Near Surface ◽  
Crustal Stresses ◽  
Tectonically Active

<p>The Fracture Induced Electromagnetic Radiation (FEMR) technique has gradually progressed in the past decade as a useful geophysical tool to determine the direction and magnitude of recent crustal stresses, visualize the modification and realignment of stresses inside tunnels thus proving to be an important precursor for geohazards, earthquake forecasting, as well as delineate landslide-prone slip planes in unstable regions. Its working principle is based on the generation of geogenic electromagnetic radiation emanating from the brittle rock bodies that are fractured being subjected to an incremental increase of the differential stress in the near-surface of the Earth’s crust. The “Process zone” at the fractured crack tip contains numerous microcracks which subsequently creates dipoles due to the polarization of charges on such microcrack tips which rapidly oscillates emitting FEMR waves of frequencies between KHz to MHz range. The coalescence of the microcracks eventually leads to a macro failure dampening the amplitude of the FEMR pulses. The attenuation of FEMR pulses is comparatively lesser than seismic waves making it a more efficient precursor to potential tectonic activities indicating an upcoming earthquake a few hours/days before the actual event. In the current study, we have attempted to exploit this technique to identify the locations of the potential active faults across the tectonically active Narmada-Son Lineament (NSL), Central India. Although the first tectonic stage involved rifting and formation of the NSL during the Precambrian time, the rifting continued at least till the time of Gondwana deposition. Later, tectonic inversion took place as a result of the collision between the Indian and the Eurasian plate resulting in reverse reactivation of the faults. Episodic reverse movement along NSL caused recurrent earthquakes and linear disposition of the sediments that were deposited at the foothills of the Satpura Horst. Although the origin of East-West trending NSL dates back to the Precambrian time, it is very much tectonically active as manifested by recent earthquakes. The study has been conducted by taking linear FEMR readings across 3 traverses along the NSL which on analysis provides an idea about the potential active faults, their locations, and frequency of occurrence. The accumulation of strain in the brittle rocks that can eventually lead to a macro failure is demarcated as an anomalous increase in the amplitude of the FEMR pulses indicative of an upcoming tectonic episode in the region. To further corroborate the analysis, we have attempted to determine the neo-tectonic activity in the region by calculating the morphometric parameters across the Khandwa-Itarsi-Jabalpur region, Central India. Finally, we attempt to comment on the tectonic evolution of Central India in the recent past. We also encourage researchers to adapt the novel technique of FEMR which is swift, affordable, and feasible compared to conventional techniques deployed to survey the active tectonics of a region.</p>

Cyclicity of paleofluid infiltration in the active Mount Morrone Fault System (central Apennines, Italy) constrained by carbonate concretions

2020 ◽  
Author(s):  
Gianluca Vignaroli ◽  
Valentina Argante ◽  
Federico Rossetti ◽  
Lorenzo Petracchini ◽  
Michele Soligo ◽  
...  
Keyword(s):  
Regional Scale ◽  
Active Faults ◽  
Fluid Pressure ◽  
Fault System ◽  
Tectonic Activity ◽  
Middle Pleistocene ◽  
Recurrence Time ◽  
Seismic Cycle ◽  
Central Apennines ◽  
Carbonate Concretions

<p>Active faults are characterized by creation/destruction of secondary (tectonic) permeability in response to a continuous interplay between deformation and fluid pressure fluctuations during the seismic cycle. The study of the paleofluid circulation in fault rocks can thus provide insights into the hydraulic and mechanical behavior of the seismogenic crust.</p><p>This work integrates data from field geology with geochemical and geochronological constraints to understand the spatio-temporal evolution of the paleofluid circulation in the Mount Morrone Fault System (MMFS), a ~25 km-long tectonic structure activated during the extensional Quaternary phase of the central Apennines (Italy). The MMFS cuts through a Mesozoic-Cenozoic multilayer carbonate succession for a cumulative stratigraphic offset of about 2 km. Fluvio-lacustrine and slope deposits (Middle-Late Pleistocene) occur at its hanging wall and are variably involved by faulting. The MMFS is currently classified as a silent seismic fault, with an estimated Mw= 6.5-7.0 potential magnitude and recurrence time at 2.4 ka for an expected earthquake.</p><p>The structural survey focused on the western strand of the MMFS cutting through a succession of Sinemurian dolomitized limestones. A composite network of NW-SE-striking, SW-dipping fault surfaces defines the structural architecture of the MMFS in the study outcrops, with high angle (dip > 55°) faults that systematically cut and displace medium-to-low angle (dip in the order of 30°-50°) faults. Both fault systems are characterized by dominant dip-slip movement and normal kinematics. Lenses of cm-thick cataclasites often occur along the slip surfaces. Cataclasites are made by sub-angular to sub-rounded carbonate clasts (up to 1 cm-wide) dispersed in a very fine-grained matrix. Layers of cm-thick carbonate concretions occur associated with the cataclasites, testifying for pulses of fluid discharge along the fault surface during the tectonic activity of the MMFS. Microstructural investigations document that: (i) carbonate concretions show an internal texture of fibrous vein having fiber growth direction roughly perpendicular to the vein wall, and (ii) the basal portions of the carbonate concretions are fractured and incorporated within the underlying cataclasites through the deposition of a new calcite cement. The geochemical (δ<sup>13</sup>C and δ<sup>18</sup>O stable isotope) analyses on selected samples attest for a progressive chemical shift of the mineralizing fluid from marine (in host rock and in cataclasites) to meteoric waters (in carbonate concretions). The U-Th dating of carbonate concretions and calcite slickenfibers constrains the fault-controlled fluid circulation to the Middle Pleistocene, with ages spanning from 270 to 180 ka. Significantly, the dating of carbonate concretions documents a 12-kyr cyclicity of the fluid infiltration in the fault zone.</p><p>The development of the secondary permeability in the MMFS thus corresponds to a combination of faulting and tensile fracturing, in response to a cyclic increasing of the shear stress and the pore pressure during the seismic cycle. The polyphasic deformation system of the MMFS constitutes a record of fault activation and reactivation episodes that could contribute to define the recurrence model of seismic events on regional-scale faults.</p>

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.

scholarly journals Quaternary tectonic activity of Maradona Fault System, Central Precordillera, Argentina

2018 ◽  
Vol 45 (2) ◽  
pp. 145 ◽  
Author(s):  
Gabriela Lara Ferrero ◽  
Laura Perucca ◽  
Martin Rothis ◽  
Ana Pantano ◽  
Mauro Saez
Keyword(s):  
Geological Structure ◽  
Fault System ◽  
Tectonic Activity ◽  
San Juan ◽  
Differential Gps ◽  
Sedimentary Deposits ◽  
Seismogenic Source ◽  
San Juan River ◽  
Internal Deformation ◽  
Fault Scarps

Several parallel east verging thrusts with Quaternary tectonic activity have been identified in the eastern piedmont of Cordón de Las Osamentas, Central Precordillera of Argentina. We grouped these structures into the Maradona Fault System (MFS). The main morphostructural units, called mountainous and transitional, were analyzed. The form and evolution of these units are closely related to the geological structure of the area. With the morphotectonic analysis, we estimated the length of MFS and the affected alluvial levels. Besides, the morphology of the escarpments was determined through detailed transversal topographic profiles made in a sector where the alluvial levels are affected by the faults. This analysis allowed the recognition of several fault segments and the selection of the points that would present the best natural exposures of the fault- sedimentary deposits relationships. Topographic profiles performed with differential GPS let to identify centimetric fault scarps through slope changes observed in each transect orthogonal to the direction of the structures. Five natural exposures were identified allowing determination of the kinematics of the different fault sections and the deposits affected by these structures. In all the analyzed exposures, faults are reverse with low angle (thrust), dipping to the west and affecting Neogene deposits and alluvial units assigned to the late Pleistocene-Holocene. The Maradona fault system affects younger alluvial levels to the east, showing the gradual migration of the Andean deformation eastward. The progression of the deformation in this sector of Central Precordillera would have evolved according to a pattern of thrusts with angles in surface near 45°, with sequences of internal deformation and reactivation during the Pleistocene-Holocene. Finally, the SFM is regarded as a potential seismogenic source capable to produce earthquakes with magnitude >Mw 6 and hit the main populated centers of the province of San Juan (>700,000 inhabitants), and several dams built along the San Juan River.

scholarly journals Evidence of active tectonics in the Augusta Basin (eastern Sicily, Italy) by Chirp sub-bottom sonar investigation

2014 ◽  
Vol 56 (5) ◽  
Author(s):  
Claudia Pirrotta ◽  
Maria Serafina Barbano ◽  
Daniela Pantosti ◽  
Paolo Marco De Martini
Keyword(s):  
Active Faults ◽  
Active Tectonics ◽  
Fault System ◽  
Normal Faults ◽  
Strong Earthquakes ◽  
The Holocene ◽  
Regional Seismicity ◽  
Holocene Sediments ◽  
Recent Activity ◽  
Fault Scarps

<p>A Chirp sub-bottom sonar investigation was performed in the 150 km<sup>2</sup> wideAugustaBasin, located in the eastern Sicily Ionian coast, a region repeatedly hit by strong earthquakes in historical time, with the end of identifying possible evidence of active tectonics. Seismostratigraphy shows two main reflectors: R1, formed between 60 ka and 19 ka BP, and R2 that is the top of the Holocene deposits. Morphobathymetry reveals two marine abrasion surfaces, Ms1 and Ms2 that are related to the 35 ka and 25 ka BP marine high stills, respectively. This study highlights that R1 and the onlapping Holocene sediments are affected by normal and probably strike-slip faulting. A set of NE-SW striking normal faults represents the oldest system, because they dislocate R1 but not the Holocene deposit. NNW-SSE striking extensional faults show more recent activity since they displace Ms2, the Holocene sequence and cause seafloor up-warping. NE-SW normal faults produce asymmetric basins where the Holocene deposits form wedged bodies. ENE-WSW left-lateral faults dissect a paleo-island, Ms2 and the NNW-SSE fault system. Moreover, seismically induced  slumps involving the Holocene sediments, are found at the foot of some fault scarps. The presence of slumped bodies and active faults indicates ongoing deformation in the basin. Identified active faults are consistent with the main regional Malta Escarpment fault system, of which they can be considered as the incipient westernmost extension. This study supports the hypothesis that the Malta Escarpment is active and can be responsible for the regional seismicity.</p>

scholarly journals Holocene surface-rupturing earthquakes on the Dinaric Fault System, western Slovenia

Solid Earth ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 2211-2234
Author(s):  
Christoph Grützner ◽  
Simone Aschenbrenner ◽  
Petra Jamšek Rupnik ◽  
Klaus Reicherter ◽  
Nour Saifelislam ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Active Faults ◽  
Historical Seismicity ◽  
Fault System ◽  
Historical Event ◽  
Near Surface ◽  
Geological Evidence ◽  
Geophysical Surveys ◽  
Deformation Features ◽  
Surface Ruptures

Abstract. The Dinaric Fault System in western Slovenia, consisting of NW–SE-trending, right-lateral strike-slip faults, accommodates the northward motion of Adria with respect to Eurasia. These active faults show a clear imprint in the morphology, and some of them hosted moderate instrumental earthquakes. However, it is largely unknown if the faults also had strong earthquakes in the late Quaternary. This hampers our understanding of the regional tectonics and the seismic hazard. Geological evidence of co-seismic surface ruptures only exists for one historical event, the 1511 Idrija earthquake with a magnitude of ∼ M 6.8, but the causative fault is still disputed. Here we use geomorphological data, near-surface geophysical surveys, and paleoseismological trenching to study two of these faults: the Predjama Fault and the Idrija Fault. In a paleoseismological trench across the Predjama Fault we found deformation features that may have been caused by an earthquake between 13–0.7 ka, very likely not earlier than 8.4 ka. At the Idrija Fault, a surface-rupturing earthquake happened around 2.5 ka. We show that instrumental and historical seismicity data do not capture the strongest events in this area.

scholarly journals Holocene surface rupturing earthquakes on the Dinaric Fault System, western Slovenia

2021 ◽  
Author(s):  
Christoph Grützner ◽  
Simone Aschenbrenner ◽  
Petra Jamšek Rupnik ◽  
Klaus Reicherter ◽  
Nour Saifelislam ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Active Faults ◽  
Historical Seismicity ◽  
Fault System ◽  
Historical Event ◽  
Near Surface ◽  
Geological Evidence ◽  
Strong Earthquakes ◽  
Geophysical Surveys ◽  
Seismic Moment Release

Abstract. The Dinaric Fault System in western Slovenia, consisting of NW-SE trending, right-lateral strike-slip faults, accommodates the northward motion of Adria with respect to Eurasia. These active faults show a clear imprint in the morphology and some of them hosted moderate instrumental earthquakes. However, it is largely unknown if the faults also had strong earthquakes in the Late Quaternary. This hampers our understanding of the regional tectonics and the seismic hazard. Geological evidence of co-seismic surface ruptures only exists for one historical event, the 1511 Idrija Earthquake with a magnitude of ~M6.8, but the causative fault is still disputed. Here we use geomorphological data, near-surface geophysical surveys, and paleoseismological trenching to show that two of these faults, the Predjama Fault and the Idrija Fault ruptured in strong earthquakes in the Holocene. In a paleoseismological trench across the Predjama Fault we found at least one earthquake with a minimum magnitude of MW6.1 that occurred between 13–0.7 ka, very likely not earlier than 8.4 ka. At the Idrija Fault, a surface-rupturing earthquake with a magnitude of at least MW6.1 happened in the last ~2.1 ka. This event could correspond to the 1511 Idrija earthquake. Our results show that the faults rupture in rare, but strong earthquakes, which dominate the seismic moment release. We show that instrumental and historical seismicity data do not capture the strongest events in this area. The fact that many of the NW-SE trending, parallel faults are active implies that the deformation in western Slovenia is distributed, rather than focussed on one major structure.

scholarly journals Local radon flux maxima in the quaternary sediments of Schleswig–Holstein (Germany)

2021 ◽  
Author(s):  
Johannes Albert ◽  
Maximilian Schärf ◽  
Frieder Enzmann ◽  
Martin Waltl ◽  
Frank Sirocko
Keyword(s):  
Water Content ◽  
Pore Space ◽  
Mineralogical Composition ◽  
Fault System ◽  
Near Surface ◽  
Salt Diapirism ◽  
The North ◽  
Radon Flux ◽  
Published Evidence ◽  
Tectonically Active

AbstractThis paper presents radon flux profiles from four regions in Schleswig–Holstein (Northern Germany). Three of these regions are located over deep-rooted tectonic faults or salt diapirs and one is in an area without any tectonic or halokinetic activity, but with steep topography. Contrary to recently published studies on spatial patterns of soil radon gas concentration we measured flux of radon from soil into the atmosphere. All radon devices of each profile were deployed simultaneously to avoid inconsistencies due to strong diurnal variations of radon exhalation. To compare data from different seasons, values had to be normalized. Observed radon flux patterns are apparently related to the mineralogical composition of the Quaternary strata (particularly to the abundance of reddish granite and porphyry), and its grain size (with a flux maximum in well-sorted sand/silt). Minimum radon flux occurs above non-permeable, clay-rich soil layers. Small amounts of water content in the pore space increase radon flux, whereas excessive water content lessens it. Peak flux values, however, are observed over a deep-rooted fault system on the eastern side of Lake Plön, i.e., at the boundary of the Eastholstein Platform and the Eastholstein Trough. Furthermore, high radon flux values are observed in two regions associated with salt diapirism and near-surface halokinetic faults. These regions show frequent local radon flux maxima, which indicate that the uppermost strata above salt diapirs are very inhomogeneous. Deep-rooted increased permeability (effective radon flux depth) or just the boundaries between permeable and impermeable strata appear to concentrate radon flux. In summary, our radon flux profiles are in accordance with the published evidence of low radon concentrations in the “normal” soils of Schleswig–Holstein. However, very high values of radon flux are likely to occur at distinct locations near salt diapirism at depth, boundaries between permeable and impermeable strata, and finally at the tectonically active flanks of the North German Basin.

Bathymetry and uplift rate of the Gulf of Aqaba, Dead Sea Fault.

2021 ◽  
Author(s):  
Matthieu Ribot ◽  
Yann Klinger ◽  
Edwige Pons-Branchu ◽  
Marthe Lefevre ◽  
Sigurjón Jónsson
Keyword(s):  
High Resolution ◽  
Tectonic Evolution ◽  
Active Faults ◽  
Major Change ◽  
Dead Sea ◽  
Fault System ◽  
Arabian Plate ◽  
Gulf Of Aqaba ◽  
Uplift Rate ◽  
The Dead

&lt;p&gt;Initially described in the late 50&amp;#8217;s, the Dead Sea Fault system connects at its southern end to the Red Sea extensive system, through a succession of left-stepping faults. In this region, the left-lateral differential displacement of the Arabian plate with respect to the Sinai micro-plate along the Dead Sea fault results in the formation of a depression corresponding to the Gulf Aqaba. We acquired new bathymetric data in the areas of the Gulf of Aqaba and Strait of Tiran during two marine campaigns (June 2018, September 2019) in order to investigate the location of the active faults, which structure and control the morphology of the area. The high-resolution datasets (10-m posting) allow us to present a new fault map of the gulf and to discuss the seismic potential of the main active faults.&lt;/p&gt;&lt;p&gt;We also investigated the eastern margin of the Gulf of Aqaba and Tiran island to assess the vertical uplift rate. To do so, we computed high-resolution topographic data and we processed new series of U-Th analyses on corals from the uplifted marine terraces.&lt;/p&gt;&lt;p&gt;Combining our results with previous studies, we determined the local and the regional uplift in the area of the Gulf of Aqaba and Strait of Tiran.&lt;/p&gt;&lt;p&gt;Eventually, we discussed the tectonic evolution of the gulf since the last major change of the tectonic regime and we propose a revised tectonic evolution model of the area.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

The Fairbanks earthquakes of June 21, 1967; aftershock distribution, focal mechanisms, and crustal parameters

1969 ◽  
Vol 59 (1) ◽  
pp. 73-100
Author(s):  
Larry Gedney ◽  
Eduard Berg
Keyword(s):  
P Wave ◽  
Fault System ◽  
Crustal Layer ◽  
Near Surface ◽  
Fault Surface ◽  
True Value ◽  
Regional Tectonic ◽  
Tectonic System ◽  
Relationship Of ◽  
The Relationship

Abstract A series of moderately severe earthquakes occurred in the vicinity of Fairbanks, Alaska, on the morning of June 21, 1967. During the following months, many thousands of aftershocks were recorded in order to outline the aftershock zone and to resolve the focal mechanism and its relation to the regional tectonic system. No fault is visible at the surface in this area. Foci were found to occupy a relatively small volume in the shape of an ablate cylinder tilted about 30° from the vertical. The center of the zone lay about 12 kilometers southeast of Fairbanks. Focal depths ranged from near-surface to 25 kilometers, although most were in the range 9-16 km. In the course of the investigation, it was found that the Jeffreys and Bullen velocity of 5.56 km/sec for the P wave in the upper crustal layer is very near the true value for this arec, and that the use of 1.69 for the Vp/Vs ratio gives good results in most cases. The proposed faulting mechanism involves nearly equal components of right-lateral strike slip, and normal faulting with northeast side downthrown on a system of sub-parallel faults striking N40°W. The fault surface appears to be curved—dipping from near vertical close to the surface to less steep northeast dips at greater depths. The relationship of this fault system with the grosser aspects of regional tectonism is not clear.

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