scholarly journals Geometry and kinematics of the Baza Fault (central Betic Cordillera, South Spain): insights into its seismic potential

2020 ◽  
Vol 18 ◽  
pp. 1-25
Author(s):  
I. Medina-Cascales ◽  
I. Martin-Rojas ◽  
F.J. García-Tortosa ◽  
J.A. Peláez ◽  
P. Alfaro
Keyword(s):  
Structural Characterization ◽  
Damage Zone ◽  
Active Faults ◽  
Normal Fault ◽  
Betic Cordillera ◽  
Surface Geometry ◽  
Seismic Potential ◽  
Vertical Displacements ◽  
Fault Kinematics ◽  
Geometry And Kinematics

The geometry and kinematics of active faults have a significant impact on their seismic potential. In this work, a structural characterization of the active Baza Fault (central Betic Cordillera, southern Spain) combining surface and subsurface data is presented. Two sectors are defined based on their surface geometry: a northern sector striking N–S to NNW–SSE with a narrow damage zone and a southern sector striking NW–SE with a wide damage zone. A kinematic analysis shows pure normal fault kinematics along most of the fault. Geometric differences between the northern and southern sectors are caused by i) a heterogeneous basement controlling the fault geometry at depth and in the cover; ii) different orientations of the Baza Fault in the basement with respect to the regional extension direction and iii) interaction with other active faults. We use this structural characterization to analyse the segmentation of the Baza Fault. According to segmentation criteria, the entire Baza Fault should be considered a single fault seismogenic segment. Consequently, the seismic potential of the fault is defined for a complete rupture. Magnitude for the Mmax event is calculated using several scale relationships, obtaining values ranging between Mw 6.6 and Mw 7.1. Recurrence times range between approximately 2,000 and 2,200 years for Mmax events and between 5,300 and 5,400 years for palaeo-events. A geodetic scenario modelled for an Mmax event of Mw 6.7 shows permanent vertical displacements of more than 0.40m and an overall WSW–ENE extension during entire ruptures of the Baza Fault.

scholarly journals Recent and active faults and folds in the central-eastern Internal Zones of the Betic Cordillera

2012 ◽  
Vol 38 (1) ◽  
Author(s):  
A. Pedrera ◽  
J. Galindo-Zaldívar ◽  
C. Marín-Lechado ◽  
F.J. García-Tortosa ◽  
P. Ruano ◽  
...  
Keyword(s):  
Active Faults ◽  
Betic Cordillera ◽  
Central Eastern

scholarly journals Seismic Activity of the Manisa Fault Zone in Western Turkey Constrained by Cosmogenic 36Cl Dating

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 451
Author(s):  
Nasim Mozafari ◽  
Çağlar Özkaymak ◽  
Dmitry Tikhomirov ◽  
Susan Ivy-Ochs ◽  
Vasily Alfimov ◽  
...  
Keyword(s):  
Fault Zone ◽  
Normal Fault ◽  
Vertical Displacement ◽  
Historical Records ◽  
Western Turkey ◽  
Slip Rates ◽  
Vertical Displacements ◽  
Surface Ruptures ◽  
Fault Scarps ◽  
Calculated Average

This study reports on the cosmogenic 36Cl dating of two normal fault scarps in western Turkey, that of the Manastır and Mugırtepe faults, beyond existing historical records. These faults are elements of the western Manisa Fault Zone (MFZ) in the seismically active Gediz Graben. Our modeling revealed that the Manastır fault underwent at least two surface ruptures at 3.5 ± 0.9 ka and 2.0 ± 0.5 ka, with vertical displacements of 3.3 ± 0.5 m and 3.6 ± 0.5 m, respectively. An event at 6.5 ± 1.6 ka with a vertical displacement of 2.7 ± 0.4 m was reconstructed on the Mugırtepe fault. We attribute these earthquakes to the recurring MFZ ruptures, when also the investigated faults slipped. We calculated average slip rates of 1.9 and 0.3 mm yr−1 for the Manastır and Mugırtepe faults, respectively.

scholarly journals Testing the effects of topography, geometry and kinematics on modeled thermochronometer cooling ages in the eastern Bhutan Himalaya

2017 ◽  
Author(s):  
Michelle E. Gilmore ◽  
Nadine McQuarrie ◽  
Paul Eizenhöfer ◽  
Todd A. Ehlers
Keyword(s):  
Cross Section ◽  
Kinematic Model ◽  
Main Central Thrust ◽  
Radiogenic Heat ◽  
Kinematic Evolution ◽  
Thrust Belts ◽  
Fault Kinematics ◽  
Erosional Unloading ◽  
Topographic Evolution ◽  
Geometry And Kinematics

Abstract. The temporal and kinematic evolution of fold-thrust belts is a critical component for evaluating the viability of proposed plate tectonic, geodynamic and even climatic processes in regions of convergence. Thermochronometer data have the potential to provide temporal constraints, but interpretations of these data are sensitive to both exhumational and deformational processes. In this study, reconstructions of a balanced geologic cross section in the Himalayan fold-thrust belt of eastern Bhutan are used in a flexural and thermal-kinematic model to understand the sensitivity of predicted cooling ages to changes in fault kinematics, geometry and topography. We sequentially deform the cross section with ~ 10 km deformation steps and apply flexural loading and erosional unloading at each step to develop a high-resolution evolution of deformation, erosion, and burial over time. Comparison of model-predicted cooling ages to published thermochronometer data reveals that cooling ages are most sensitive to (1) location and magnitude of fault ramps, (2) variable shortening rates between 68-6.4 mm/yr, and (3) timing and magnitude of out-of-sequence faulting. The predicted ages are less sensitive to (4) radiogenic heat production, and (5) estimates of topographic evolution. We propose a revised cross section geometry that separates one large ramp previously proposed for the modern decollement into two smaller ramps. The revised cross section results in an improved fit to observed ages, particularly young AFT ages (2–6 Ma) located north of the Main Central Thrust.

scholarly journals Identification of Paleoearthquakes and Coseismic Slips on a Normal Fault Using High-Precision Quantitative Morphology: Application to the Jiaocheng Fault in the Shanxi Rift, China

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 2) ◽  
Author(s):  
Junjie Zou ◽  
Honglin He ◽  
Yusuke Yokoyama ◽  
Adam D. Sproson ◽  
Yoshiki Shirahama ◽  
...  
Keyword(s):  
Active Faults ◽  
Normal Fault ◽  
Seismic Events ◽  
Quantitative Morphology ◽  
Coseismic Slip ◽  
Slip History ◽  
Absolute Dating ◽  
Future Work ◽  
Shanxi Rift

Abstract The quantitative morphology of bedrock fault surfaces combined with aerial surveys and field identification is a useful approach to identify paleoearthquakes, obtain coseismic slips, and evaluate the seismogenic capacity of active faults in bedrock areas where traditional trenching methods are not applicable. Here, we report a case study of the Jiaocheng Fault (JCF) in the Shanxi Rift, China. Although several studies have been conducted on the JCF, its coseismic slip history and seismogenic capacity are still unclear. To address these problems, we investigated two bedrock fault surfaces, Sixicun (SXC) and Shanglanzhen (SLZ), on the JCF’s northern segment using quantitative morphological analysis together with aerial and field surveys. Quantitative fractal analysis based on the isotropic empirical variogram and moving window shows that both bedrock fault surfaces have the characteristics of vertical segmentation, which is likely due to periodic earthquakes, the coseismic slip of which can be determined by the height of the segments. Three seismic events at SXC, with a coseismic vertical slip of 1.74, 1.65, and 1.99 m, and three seismic events at SLZ, with a coseismic vertical slip of 1.32, 2.35, and 1.88 m, are identified. Compared with the previous studies, these three seismic events may occur in the Holocene, but it requires absolute dating ages to support, which is also the focus of our future work. Considering the seismologic capability (M>7.5) and the relationship between the recurrence interval of ~2.6 kyr and elapsed time of more than 3 kyr, the seismic hazard of the northern and middle segments of the JCF requires immediate attention.

scholarly journals The Padul normal fault activity constrained by GPS data: Brittle extension orthogonal to folding in the central Betic Cordillera

2017 ◽  
Vol 712-713 ◽  
pp. 64-71 ◽  
Author(s):  
Antonio J. Gil ◽  
Jesús Galindo-Zaldívar ◽  
Carlos Sanz de Galdeano ◽  
Maria Jesús Borque ◽  
Alberto Sánchez-Alzola ◽  
...  
Keyword(s):  
Normal Fault ◽  
Betic Cordillera ◽  
Gps Data ◽  
Fault Activity

scholarly journals From ductile to brittle, late- to post-orogenic evolution of the Betic Cordillera: Structural insights from the northeastern Internal zones

2013 ◽  
Vol 184 (4-5) ◽  
pp. 405-425 ◽  
Author(s):  
Romain Augier ◽  
Laurent Jolivet ◽  
Damien Do couto ◽  
François Negro
Keyword(s):  
Shear Zone ◽  
Sedimentary Cover ◽  
Active Faults ◽  
Sedimentary Basins ◽  
Strike Slip ◽  
Betic Cordillera ◽  
Small Scale ◽  
Extensional Tectonics ◽  
Stress Regime ◽  
Meso Scale

Abstract Relations between Alpine detachment-bounded metamorphic domes, crustal-scale strike-slip fault zones and sedimentary basins in the Internal zones of the Betic cordillera are still matter of debate. Current tectonic interpretations of these basins vary from late-orogenic extensional structures to compressional ones associated with strike-slip motions along major still active faults. Structural investigations including new field mapping, meso-scale faults recognition, palaeostress analysis of brittle small-scale faults systems were performed in the sedimentary cover of the Almanzora corridor and the Huércal-Overa basins, located either in the hanging wall unit of the Filabres extensional shear zone or at the termination of the Alhama de Murcia sinistral fault zone. In parallel, a detailed study of the ductile and the ductile-brittle deformation was carried out in the footwall unit of the Filabres extensional shear zone, in the Nevado-Fílabride complex. Three main brittle events were recognised in the basin cover including two extensional events that occurred prior to a weak tectonic inversion of the basin during a third, still active event. The first one, D1b is characterized by the development a first stress regime consistent with ~NW-SE extensional tectonics. Besides, the consistency between the latest ductile and the brittle kinematics for the Filabres extensional shear zone and the activity of meso-scale fault systems that primarily control the main SW-NE depocentres allow concluding to a top-to-the-NW continuum of strain during the final exhumation of the Nevado-Filábride complex. The resulting overall half-graben architecture of the basins is then related to the combination of the formation of the metamorphic domes that added a local control superimposed on the regional deformation. Indeed, after a consistent top-to-the-west shearing prevailing during most of the Nevado-Filábride exhumation, final exhumation stages were in turn, characterised by important kinematics changes with a subordinate top-to-the-NW sense of shear (D1b). The onset of sedimentation in the basins occurred shortly after the crossing of the ductile-brittle transition in the underlying metamorphic domes at ca. 14 Ma into SW-NE fault-bounded troughs. Tectonic subsidence was then maintained during D2b while extensional kinematics changed to N-S or even locally to SSW-NNE. Extensional tectonics then lasted most of the Tortonian during the final tectonic denudation increments of the Sierra de los Filabres achieved at ca. 9-8 Ma. Intramontane basins are therefore genuinely extensional and clearly related to the latest exhumation stages of the Nevado-Filábride complex in the back-arc domain. Conversely, at ca. 8 Ma, basins started to record a ~N-S to NNW-SSE compressional stress regime (D3b) and ceased to be active depocentres while shortening within the Internal zones then recorded only the Iberia/Africa convergence. The weak inversion of the basins however resulted either in the reactivation of originally extensional faults such as the Alhama de Murcia fault or the basin individualisation and a progressive water exchange reduction with the Atlantic ocean and is thus proposed to be directly responsible for the Late Miocene salinity crises.

scholarly journals Measurements of tectonic micro-displacements within the Idrija fault zone in the Učja valley (W Slovenia)

2020 ◽  
Vol 60 (1) ◽  
Author(s):  
Andrej Gosar
Keyword(s):  
Fault Zone ◽  
Active Fault ◽  
Average Rate ◽  
Active Faults ◽  
Slip Rate ◽  
Seismic Hazard Assessment ◽  
Vertical Displacements ◽  
Recent Activity ◽  
Insight Into ◽  
Horizontal Displacements

A recent slip-rate of an active fault is a very important seismotectonic parameter, but not easy to determine. Idrija fault, 120 km long, is a prominent geomorphologic feature with large seismogenic potential, still needed to be researched. Measurements of tectonic micro-displacements can provide insight into its recent activity. The Učja valley extends transversally to the Idrija fault and was therefore selected for the installation of TM 71 extensometer. Measurements on the crack within its inner fault zone are conducted from the year 2004. In 14 years of observations a systematic horizontal displacements with average rate of 0.21 mm/year and subordinate vertical displacements of 0.06 mm/year were established, proving the activity of this fault. An overview of methods of displacement measurements related to active faults and of newer interdisciplinary investigations of the Idrija fault is given. Displacement rates are beside for geodynamic interpretations important for improvement of seismotectonic models and thus for better seismic hazard assessment.

scholarly journals Realistic modelling of faults in LoopStructural 1.0

2021 ◽  
Author(s):  
Lachlan Grose ◽  
Laurent Ailleres ◽  
Gautier Laurent ◽  
Guillaume Caumon ◽  
Mark Jessell ◽  
...  
Keyword(s):  
Kinematic Model ◽  
Sampled Data ◽  
Implicit Surface ◽  
Surface Geometry ◽  
Data Set ◽  
Multiple Faults ◽  
Fault Surface ◽  
Fault Kinematics ◽  
Continuous Surface ◽  
Surface Description

Abstract. Without properly accounting for both fault kinematics and faulted surface observations, it is challenging to create 3D geological models of faulted geological units that are seen in all tectonic settings. Geometries where multiple faults interact, where the faulted surface geometry significantly deviate from a flat plane and where the geological interfaces are poorly characterised by sparse data sets are particular challenges. There are two existing approaches for incorporating faults into geological surface modelling: one approach incorporates the fault displacement into the surface description but does not incorporate fault kinematics and in most cases will produce geologically unexpected results such as shrinking intrusions, fold hinges without offset and layer thickness growth in flat oblique faults. Another approach builds a continuous surface without faulting and then applies a kinematic fault operator to the continuous surface to create the displacement. Both approaches have their strengths, however neither approach can capture the interaction of faults within complicated fault networks e.g fault duplexes, flower structures and listric faults because they either \\begin{inparaenum}[(1)] \\item impose an incorrect (not defined by data) fault slip direction; or \\item require an over sampled data set that describes the faulted surface location\\end{inparaenum}. In this study we integrate the fault kinematics into the implicit surface by using the fault kinematic model to restore observations and the model domain prior to interpolating the faulted surface. This approach can build models that are consistent with observations of the faulted surface and fault kinematics. Integrating fault kinematics directly into the implicit surface description allows for complex fault stratigraphy and fault-fault interactions to be modelled. Our approaches show significant improvement in capturing faulted surface geometries especially where the intersection angle between the faulted surface geometry and the fault surface varies (e.g. intrusions, fold series) and when modelling interacting faults (fault duplex).

Sign in / Sign up

Export Citation Format

Share Document