Filtering by Subject: Tectonics and Structure

Coupling between shallow and deep fault populations governs along-strike variations in fault reactivation and structural inheritance, the Laminaria High, NW Shelf of Australia

Thomas Brian Phillips, Ken McCaffrey, Luke Magarinos

Published: 2021-05-13
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure

When extension events are greatly separated in time, older faults may be buried and stratigraphically separated from newly developing faults at shallower depths. During rifting, the buried structures may reactivate and propagate upwards to be expressed within the shallow system. The degree of linkage between structural levels determines the influence that the deeper structures can exert over the [...]

Structural Inheritance Controls Strain Distribution During Early Continental Rifting, Rukwa Rift

Folarin Kolawole, Thomas B. Phillips, Estella A. Atekwana, Christopher A-L Jackson

Published: 2021-05-13
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure

Little is known about rift kinematics and strain distribution during the earliest phase of extension due to the deep burial of the pre-rift and earliest rift structures beneath younger, rift-related deposits. Yet, this exact phase of basin development ultimately sets the stage for the location of continental plate divergence and breakup. Here, we investigate the structure and strain distribution [...]

The influence of crustal strength on rift geometry and development – Insights from 3D numerical modelling

Thomas Brian Phillips, John Naliboff, Ken McCaffrey, Sophie Pan, Jeroen van Hunen

Published: 2021-05-07
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure

The lateral distribution of strength within the crust is highly variable. When subject to extension, lithologically and rheologically distinct areas of crust manifest strain differently, influencing the structural style, geometry and evolution of the associated rift system. Here, we use 3D thermo-mechanical models of continental extension to explore how pre-rift upper crustal strength variations [...]

Fracture distribution in a folded fluvial succession: the Puig-reig anticline (South-eastern Pyrenees)

Xiaolong Sun, Enrique Gomez-Rivas, Juan Alcalde, Juan Diego Martín-Martín, Cunfei Ma, Daniel Muñoz-López, David Cruset, Irene Cantarero, Albert Griera, Anna Travé

Published: 2021-05-07
Subjects: Geology, Sedimentology, Stratigraphy, Tectonics and Structure

Sedimentary rocks of foreland fold-and-thrust belts typically undergo intensive fracturing as fold grows. The resulting fracture networks can present significant variations depending on the distribution of sedimentary facies and the complex structural characteristics of fold-and-thrust belts. The Puig-reig anticline, located in the south-eastern Pyrenees, mainly exposes proximal fluvial deposits [...]

Syn- to post-rift alluvial basin fill: seismic stratigraphic analysis of Permian-Triassic deposition in the Horda Platform, Norway

Camilla Würtzen, Johnathon Lee Osmond, Jan Inge Faleide, Johan Petter Nystuen, Ingrid Margareta Anell, Ivar Midtkandal

Published: 2021-05-02
Subjects: Geology, Geomorphology, Sedimentology, Stratigraphy, Tectonics and Structure

Discrepancies in models of continental rift-basin dynamics and stratigraphic response calls on further investigation on the subject. Geometric- and lithological trends between stages of faulting is studied in the Permian- Triassic continental rift succession in the Horda Platform. The Horda Platform occupies the northeastern margin of the North Sea aulacogen where Late Permian-Early Triassic [...]

Bridging spatiotemporal scales of normal fault growth using numerical models of continental extension

Sophie Pan, John Naliboff, Rebecca E. Bell, Chris Jackson

Published: 2021-04-21
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Other Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure

Continental extension is accommodated by the development of kilometre-scale normal faults, which grow by accumulating metre-scale earthquake slip over millions of years. Reconstructing the entire lifespan of a fault remains challenging due to a lack of observational data of appropriate scale, particularly over intermediate timescales (10^4-10^6 yrs). Using 3D numerical simulations of continental [...]


Emanuele Scaramuzzo, Franz A. Livio, Pablo Granado, Raffaele Bitonte, Andrea Di Capua

Published: 2021-04-20
Subjects: Tectonics and Structure

Recently, the influence of lithospheric extension on later orogeny has gained increasing interest. We make use of own geological mapping, interpretations of seismic reflection profiles and deep geophysical data to build an area-balanced cross-section across a key area of the Western Southern Alps and to model a series of structural restorations from the end of Mesozoic rifting to present-day. The [...]

The 2019-2020 Indios, Puerto Rico earthquake sequence: seismicity and faulting

Blaž Vičič, Seyyedmaalek Momeni, Alessandra Borghi, Anthony Lomax, Abdelkrim Aoudia

Published: 2021-04-20
Subjects: Geophysics and Seismology, Tectonics and Structure

The 2019-2020 Indios, Puerto Rico earthquake sequence ruptured on multiple faults with several moderate magnitude earthquakes. Here we investigate the seismotectonics of this fault system using high precision hypocenter relocation and inversion of the near-field strong motions of five largest events in the sequence (5.6≤Mw≤6.4) for kinematic rupture models. The Mw6.4 mainshock occurred on an NE [...]

The Mid-Lithospheric Discontinuity caused by channel flow in the cratonic lithosphere

Haibin Yang, Irina Artemieva, Hans Thybo

Published: 2021-04-20
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

Stable cratons with a thick (> 200 km) and cold lithosphere form rheologically strong plates that move atop a ductile asthenospheric mantle. Various types of seismic observations show the presence of a potentially rheologically weak zone at depths of ca. 80 – 150 km termed the Mid-Lithosphere Discontinuity (MLD). While various mechanisms may explain the MLD, the dynamic processes leading to the [...]

Stress and Strain during Shock Metamorphism

Auriol S. P. Rae, Michael H. Poelchau, Thomas Kenkmann

Published: 2021-04-15
Subjects: Geology, Planetary Geology, Planetary Geophysics and Seismology, Tectonics and Structure

Shock metamorphism is the process by which rocks, and the minerals within them, transform during the passage of a shock wave. Shock effects, such as shatter cones, are critical for the identification of impact structures and have commonly been used to infer mechanical and structural information on the cratering process. To make these inferences, the mechanics of shock wave behavior must be [...]

Structure of the deep lithosphere between Pamir and Tarim

Wasja Bloch, Bernd Schurr, Xiaohui Yuan, Lothar Ratschbacher, Sanaa Reuter, Sofia‑Katerina Kufner, Qiang Xu, Junmeng Zhao

Published: 2021-04-14
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

The Pamir orogen protrudes $\sim$300-km between the Tajik and Tarim lithosphere of central Asia. It is debated, whether its salient location and shape is controlled by indentation of a promontory of Indian mantle lithosphere or by rollback of thinned Tarim--Tajik-basin lithosphere. We present a new local-seismicity and focal-mechanism catalog and a P-wave velocity model [...]

Rectangular drainage pattern evolution controlled by pipe cave collapse along clastic dikes, the Dead Sea Basin, Israel

Liran Goren, Matanya Hamawi, Amit Mushkin, Tsafrir Levi

Published: 2021-04-09
Subjects: Geomorphology, Tectonics and Structure

Coulomb Threshold Rate-and-State Model for Fault Reactivation: Application to induced seismicity at Groningen

Elias Rafn Heimisson, Jonathan D Smith, Jean-Philippe Avouac, Stephen Bourne

Published: 2021-04-06
Subjects: Environmental Monitoring, Geophysics and Seismology, Tectonics and Structure

A number of recent modeling studies of induced seismicity have used the rate-and-state friction model of Dieterich (1994) to account for the fact that earthquake nucleation is not instantaneous. Notably, the model assumes a population of seismic sources accelerating towards instability with a distribution of intial slip speeds such that they would produce earthquakes steadily in absence of any [...]

Dilatancy and compaction of a rate-and-state fault in a poroelastic medium: Linearized stability analysis

Elias Rafn Heimisson, John Rudnicki, Nadia Lapusta

Published: 2021-04-06
Subjects: Applied Mathematics, Geophysics and Seismology, Tectonics and Structure

Faults in the crust at seismogenic depths are embedded in a fluid-saturated, elastic, porous material. Slip on such faults may induce transient pore pressure changes through dilatancy or compaction of the gouge or host rock. However, the poroelastic nature of the crust and the full coupling of inelastic gouge processes and the host rock have been largely neglected in previous analyses. Here, we [...]

Resolving Northern Alaska Earthquake Sequences Using the Transportable Array and Probabilistic Location Methods

Steven John Gibbons, Natalia Ruppert, Ezgi Karasözen, Kasey Aderhold, Ian Dickson

Published: 2021-03-25
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

Between 2014 and 2017, almost 200 new seismic stations were installed in Alaska and northwestern Canada as part of the EarthScope USArray Transportable Array. These stations currently provide an unprecedented capability for the detection and location of seismic events in regions with otherwise relatively sparse station coverage. Two interesting earthquake sequences in 2018 and 2019 in the [...]


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