Mid-crustal controls on episodic stress-field rotation around major reverse, normal and strike-slip faults

2011 ◽  
Vol 359 (1) ◽  
pp. 187-201 ◽  
Author(s):  
Jens-Alexander Nüchter ◽  
Susan Ellis
Keyword(s):  
Stress Field ◽  
Strike Slip ◽  
Episodic Stress ◽  
Field Rotation

scholarly journals Three-dimensional approach to understanding the relationship between the Plio-Quaternary stress field and tectonic inversion in the Triassic Cuyo Basin, Argentina

2015 ◽  
Vol 7 (1) ◽  
pp. 459-494
Author(s):  
L. Giambiagi ◽  
S. Spagnotto ◽  
S. M. Moreiras ◽  
G. Gómez ◽  
E. Stahlschmidt ◽  
...  
Keyword(s):  
Stress Field ◽  
Three Dimensional ◽  
Sedimentary Basins ◽  
Strike Slip ◽  
Stress Regime ◽  
Basin Inversion ◽  
Structural Style ◽  
Tectonic Inversion ◽  
The Impact ◽  
The Relationship

Abstract. The Cacheuta sub-basin of the Triassic Cuyo Basin is an example of rift basin inversion contemporaneous to the advance of the Andean thrust front, during the Plio-Quaternary. This basin is one of the most important sedimentary basins in a much larger Triassic NNW-trending depositional system along the southwestern margin of the Pangea supercontinent. The amount and structural style of inversion is provided in this paper by three-dimensional insights into the relationship between inversion of rift-related structures and spatial variations in late Cenozoic stress fields. The Plio-Quaternary stress field exhibits important N–S variations in the foreland area of the Southern Central Andes, between 33 and 34° S, with a southward gradually change from pure compression with σ1 and σ2 being horizontal, to a strike-slip type stress field with σ2 being vertical. We present a 3-D approach for studying the tectonic inversion of the sub-basin master fault associated with strike-slip/reverse to strike-slip faulting stress regimes. We suggest that the inversion of Triassic extensional structures, striking NNW to WNW, occurred during the Plio–Pleistocene in those areas with strike-slip/reverse to strike-slip faulting stress regime, while in the reverse faulting stress regime domain, they remain fossilized. Our example demonstrates the impact of the stress regime on the reactivation pattern along the faults.

A New Uniform Moment Tensor Catalog for Yunnan, China, from January 2000 through December 2014

2020 ◽  
Vol 91 (2A) ◽  
pp. 891-900
Author(s):  
Yan Xu ◽  
Keith D. Koper ◽  
Relu Burlacu ◽  
Robert B. Herrmann ◽  
Dan-Ning Li
Keyword(s):  
Stress Field ◽  
Seismic Hazard ◽  
Moment Tensor ◽  
Horizontal Stress ◽  
Strike Slip ◽  
Moment Tensors ◽  
Yunnan Region ◽  
Seismic Waveforms ◽  
The Moment ◽  
Maximum Horizontal Stress

Abstract Because of the collision of the Indian and Eurasian tectonic plates, the Yunnan Province of southwestern China has some of the highest levels of seismic hazard in the world. In such a region, a catalog of moment tensors is important for estimating seismic hazard and helping understand the regional seismotectonics. Here, we present a new uniform catalog of moment tensor solutions for the Yunnan region. Using a grid-search technique to invert seismic waveforms recorded by the permanent regional network in Yunnan and the 2 yr ChinArray deployment, we present 1833 moment tensor solutions for small-to-moderate earthquakes that occurred between January 2000 and December 2014. Moment magnitudes in the new catalog vary from Mw 2.2 to 6.1, and the catalog is complete above Mw∼3.5–3.6. The moment tensors are constrained to be purely double-couple and show a variety of faulting mechanisms. Normal faulting events are mainly concentrated in northwest Yunnan, while farther south along the Sagaing fault the earthquakes are mostly thrust and strike slip. The remaining area includes all three styles of faulting but mostly strike slip. We invert the moment tensors for the regional stress field and find a strong correlation between spatially varying maximum horizontal stress and Global Positioning System observations of horizontal ground velocity. The stress field reveals clockwise rotation around the eastern Himalayan syntaxis, with northwest–southeast compression to the east of the Red River fault changing to northeast–southwest compression west of the fault. Almost 88% of the centroid depths are shallower than 16 km, consistent with a weak and ductile lower crust.

Seismic and geodetic response to crustal deformation in Krísuvík volcanic system, southwest Iceland

2020 ◽  
Author(s):  
Revathy M. Parameswaran ◽  
Ingi Th. Bjarnason ◽  
Freysteinn Sigmundsson
Keyword(s):  
Stress Field ◽  
Crustal Deformation ◽  
High Energy ◽  
Strike Slip ◽  
Normal Faults ◽  
Seismic Zone ◽  
The South ◽  
The West ◽  
Volcanic System ◽  
Geothermal Activity

<p>The Reykjanes Peninsula (RP) is a transtensional plate boundary in southwest Iceland that marks the transition of the Mid-Atlantic Ridge (MAR) from the offshore divergent Reykjanes Ridge (RR) in the west to the South Iceland Seismic Zone (SISZ) in the east. The seismicity here trends ~N80°E in central RP and bends to ~N45°E at its western tip as it joins RR. Seismic surveys, geodetic studies, and recent GPS-based kinematic models indicate that the seismic zone is a collection of strike-slip and normal faults (e.g., Keiding et al., 2008). Meanwhile, the tectonic processes in the region also manifest as NE-SW trending volcanic fissures and normal faults, and N-S oriented dextral faults (e.g., Clifton and Kattenhorn, 2006). The largest of these fissure and normal-fault systems in RP is the Krísuvík-Trölladyngja volcanic system, which is a high-energy geothermal zone. The seismicity here predominantly manifests RP’s transtentional tectonics; however, also hosts triggered events such as those following the 17 June 2000 Mw6.5 earthquake in the SISZ (Árnadottir et al., 2004) ~80 km east of Krísuvík. Stress inversions of microearthquakes from 1997-2006 in the RP indicate that the current stress state is mostly strike-slip with increased normal component to the west, indicating that the seismicity is driven by plate diverging motion (Keiding et al., 2009). However, the geothermal system in Krísuvík is a potential secondary source for triggered seismicity and deformation. This study uses seismic and geodetic data to evaluate the activity in the Krísuvík-Trölladyngja volcanic system. The seismic data is used to identify specific areas of focused activity and evaluate variations in the stress field associated with plate motion and/or geothermal activity over space and time. The data used, within the time period 2007-2016, was collected by the the South Icelandic Lowland (SIL) seismic network operated and managed by the Iceland Meterological Office (IMO). Furthermore, variations in seismicity are compared to crustal deformation observed with TerraSAR-X images from 2009-2019. Crustal changes in the Krísuvík area are quantified to develop a model for corresponding deformation sources. These changes are then correlated with the stress-field variations determined with seismic analysis.</p>

Inversion tectonics, intracontinental fold-and-thrust belts and complex stress fields in central Europe: the history of the Franconian Basin revealed by paleostress analysis, geological maps and field observations.

2020 ◽  
Author(s):  
Saskia Köhler ◽  
Florian Duschl ◽  
Hamed Fazlikhani ◽  
Daniel Köhn
Keyword(s):  
Stress Field ◽  
Late Cretaceous ◽  
Complex Stress ◽  
Strike Slip ◽  
Stress Fields ◽  
Thrust Belt ◽  
Slip Regime ◽  
Geological Maps ◽  
Fold And Thrust Belt ◽  
Paleostress Analysis

<p>The Franconian Basin in SE Germany has seen a complex stress history indicative of several extensional and compressional phases e.g. the Iberia-Europe collision acting on a pre-faulted Variscan basement. Early Cretaceous extension is followed by Late Cretaceous inversion with syntectonic sedimentation and deformation increasing progressively from SW to NE culminating in the Franconian Line where basement rocks are thrusted over the Mesozoic cover. The development of this intracontinental fold-and-thrust belt is followed by Paleogene extension associated with the formation of the Eger Graben, which is then succeeded by a new compressional event as a consequence of the Alpine orogeny.</p><p>We use existing data from literature and geological maps and new field data to construct balanced cross-sections in order to reveal the architecture of the Cretaceous fold-and-thrust belt. In addition, we undertake paleostress analysis using a combination of fault slip information, veins and tectonic and sedimentary stylolites to identify stress events in the study area, as well as their nature and timing. Furthermore, we try to understand how basement faults influence younger faults in the cover sequence.</p><p>Our paleostress data indicates that at least five different stress events existed in Mesozoic to Cenozoic times (from old to young): (1) an N-S directed extensional stress field with E-W striking normal faults, (2) a NNE-SSW directed compressional stress field causing thrusting and folding of the cover sequence, (3) a strike slip regime with NE-SW compression and NW-SE extension, (4) an extensional event with NW-SE extension and the formation of ENE-WSW striking faults according to the formation of the Eger Graben in the E, and finally (5) a strike slip regime with NW-SE compression and NE-SW extension related to Alpine stresses. The geometry of faulting and deformation varies significantly over the regions with respect to the influence of and distance to inherited Variscan structures.</p><p>We argue that the extensional event of stress field (1) provides spacing for Early Cretaceous sedimentation in the Franconian Basin. This is followed by the creation of an intracontinental fold-and-thrust belt during stress fields (2) and (3) with a slight rotation of the main compressive stress during these events in Late Cretaceous. We associate the following extension to the development of the Eger Graben in Miocene time. Finally, a NW-SE directed compression related to Alpine stresses in an intracontinental strike-slip regime is following. Reconstruction of the Cretaceous fold-and-thrust belt reveals mainly fault propagation folding with deep detachments sitting below the cover sequence indicating thick-skinned tectonics. We argue that the Franconian Line is a thrust with a steeply dipping root that belongs to the same fold-and-thrust belt.</p>

A Systematic Study of Earthquake Source Mechanism and Regional Stress Field in the Southern Montney Unconventional Play of Northeast British Columbia, Canada

2019 ◽  
Vol 91 (1) ◽  
pp. 195-206 ◽  
Author(s):  
Alireza Babaie Mahani ◽  
Fatemeh Esfahani ◽  
Honn Kao ◽  
Michelle Gaucher ◽  
Mark Hayes ◽  
...  
Keyword(s):  
British Columbia ◽  
Stress Field ◽  
Horizontal Stress ◽  
Strike Slip ◽  
P Wave ◽  
Source Mechanism ◽  
Induced Earthquakes ◽  
Nodal Plane ◽  
Reverse Faulting ◽  
Best Fitting

Abstract We provide a close look at the source mechanism of hydraulically fractured induced earthquakes and the in situ stress field within the southern Montney unconventional play in the northeast British Columbia, Canada. P‐wave first‐motion focal mechanisms were obtained for 66 earthquakes with magnitudes between 1.5 and 4.6. Results show that strike‐slip movement is the prevailing source mechanism for the events in this area, although reverse faulting is also observed for a few earthquakes. The best‐fitting nodal plane mostly strikes at ∼N60° E, with most events having dip angles of >60°. Using the Martinez‐Garzon et al. (2014) stress inversion module, we obtained the orientation of the three principal compressive stress (S1>S2>S3) and the relative intermediate principal stress magnitude (R) in five clusters. Assuming the best‐fitting nodal plane to be the causative fault, R values are mostly between 0.8 and 0.9 suggesting that the magnitude of S2 and S3 are similar, which is consistent with strike‐slip or reverse‐faulting regimes. The plunge of S1 varies between 1° and 3°, with its trend varying between N21°E and N34°E. On the other hand, the plunge of S3 varies between 22° and 50°, with its trend varies between N68°W and N58°W. Following Lund and Townend (2007), we calculated the trend of maximum horizontal stress to vary from N22°E to N33°E, in comparison with the average trend of N41°E from the World Stress Map (Heidbach et al., 2016). Through analysis of the Coulomb failure criterion and Mohr diagrams, we estimated the amount of pore‐pressure increase necessary to initiate shear slip to range between 4 and 29 MPa (average of 14±8  MPa) in the study area.

Spatial variation in the present-day stress field and tectonic regime of Northeast Tibet from moment tensor solutions of local earthquake data

2020 ◽  
Vol 221 (1) ◽  
pp. 478-491 ◽  
Author(s):  
Zhengyang Pan ◽  
Jiankun He ◽  
Zhigang Shao
Keyword(s):  
Stress Field ◽  
Compressive Stress ◽  
Moment Tensor ◽  
Strike Slip ◽  
Focal Mechanisms ◽  
Qilian Mountains ◽  
Compression Axis ◽  
The South ◽  
Maximum Compression ◽  
Stress Orientation

SUMMARY Focal mechanism solutions and their predicted stress pattern can be used to investigate tectonic deformation in seismically active zones and contribute to understanding and constraining the kinematic patterns of the outward growth and uplift of the Tibetan Plateau. Herein, we determined the focal mechanisms of 398 earthquakes in Northeast Tibet recorded by the China National Seismic Network (CNSN) by using the cut-and-paste method. The results show that the earthquakes predominately exhibited thrust and strike-slip faulting mechanisms with very few normal events. We then combined the derived focal mechanisms with global centroid moment tensor (GCMT) catalogue solutions and previously published solutions to predict the regional distribution of the stress field through a damped linear inversion. The inversion results show that most of region is dominated by a thrust faulting regime. From the southern East Kunlun fault in the west to the northern Qilian Mountains along the Altyn Tagh fault (ATF), the maximum compression axis rotates slightly clockwise; farther to the south of the Haiyuan fault in the east, there is an evident clockwise rotation of the maximum compression axis, especially at the eastern end of the Haiyuan fault. In the Qilian Mountains, the axis of the compressive stress orientation approximately trends NE–SW, which does not markedly differ from the direction of India–Eurasia convergence, emphasizing the importance of the compressive stress in reflecting the remote effects of this continental collision. The overall spatial pattern of the principal stress axes is closely consistent with the GPS-derived horizontal surface velocity. A comparison of the stress and strain rate fields demonstrated that the orientations of the crustal stress axes and the surface strain axes were almost identical, which indicates that a diffuse model is more suitable for describing the tectonic characteristics of Northeast Tibet. Additionally, the compressive stress orientation rotated to ENE–WSW in the northern Qilian Mountains along the ATF and to ENE–WSW or E–W along the eastern part of the Haiyuan fault and its adjacent area to the south, highlighting the occurrence of strain partitioning along large left-lateral strike-slip faults or the lateral variation of crustal strength across these faults. Combining geodetic, geological and seismological results, we suggest that a hybrid model incorporating both the diffuse model associated with shortening and thickening of the upper crust and the asthenospheric flow model accounting for the low-velocity zone in the middle-lower crust may reflect the primary mode of crustal deformation in Northeast Tibet.

Buried Strike-Slip Fault Identification Technique Based on a 3D Stress Body Attribute Considering Formation Deformation and Lithologic Variation

2021 ◽  
Author(s):  
Wei Wang ◽  
Kui Wu ◽  
Lin Kang ◽  
Xiaobo Huang ◽  
Jian Yao
Keyword(s):  
Stress Field ◽  
Plate Theory ◽  
Critical Role ◽  
Sudden Change ◽  
Strike Slip ◽  
The Body ◽  
Strike Slip Fault ◽  
Wave Number ◽  
Bohai Bay ◽  
Bohai Bay Basin

Abstract The identification and interpretation of buried strike-slip faults are of great significance int the search for structural traps in oil and gas exploration. However, it is difficult to identify and interpret buried strike-slip faults from seismic profiles and variance slicing, because they may be clear at depth but vague in the shallow. This study proposes a 3D stress body attribute taking into consideration formation deformation and lithologic variation to identify buried strike-slip faults. Taking into account thin plate theory and the generalized Hooke's law, a relationship between stress field, formation deformation and lithologic variation is established. Structural curvature body is used to represent the formation deformation, which is obtained by scanning of the body dip angle and second-order derivation of the wave number domain, while Poisson's ratio and Young's modulus volumes are employed to reflect the spatial lithologic variation, which are calculated by the multivariate linear fitting method or prestack inversion. This technique is applied to the secondary structural interpretation of JinZhou 25-1 oilfield in LiaoDong Bay depression of BoHai Bay Basin. Compared with the 2000 ms variance slice, it can be seen clearly that there is a significant stress concentration zone in the location of LiaoXi buried strike-slip fault from the 3D stress body attribute slice, which is consistent with a sudden change in strata observed on the profile. The LiaoXi buried strike-slip fault has been identified and interpreted. Many structural traps greater than 20km2 have been found along its course. Among them, W structure was drilled in 2016 and about 4.5 million tons of oil was found. This suggests that the spatial distribution of buried strike-slip faults associated with tectonics can be effectively identified through the strength property of the stress field, which is greatly superior to the conventional variance-related methods. It verifies the ability of this technique in the identification and interpretation of strike-slip faults in the entire Bohai Bay Basin and thus its potentially critical role in guiding secondary seismic interpretation.

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