Comment on “The potential influence of subduction zone polarity on overriding plate deformation, trench migration and slab dip angle” by W.P. Schellart

2009 ◽  
Vol 463 (1-4) ◽  
pp. 208-213 ◽  
Author(s):  
Carlo Doglioni
Keyword(s):  
Subduction Zone ◽  
Potential Influence ◽  
Plate Deformation ◽  
Dip Angle

scholarly journals Numerical models of slab migration in continental collision zones

Solid Earth ◽  
2012 ◽  
Vol 3 (2) ◽  
pp. 293-306 ◽  
Author(s):  
V. Magni ◽  
J. van Hunen ◽  
F. Funiciello ◽  
C. Faccenna
Keyword(s):  
Subduction Zone ◽  
Plate Tectonics ◽  
Numerical Models ◽  
Continental Collision ◽  
Force Balance ◽  
Small Scale ◽  
Dip Angle ◽  
External Forces ◽  
Stress Dependent ◽  
Subduction System

Abstract. Continental collision is an intrinsic feature of plate tectonics. The closure of an oceanic basin leads to the onset of subduction of buoyant continental material, which slows down and eventually stops the subduction process. In natural cases, evidence of advancing margins has been recognized in continental collision zones such as India-Eurasia and Arabia-Eurasia. We perform a parametric study of the geometrical and rheological influence on subduction dynamics during the subduction of continental lithosphere. In our 2-D numerical models of a free subduction system with temperature and stress-dependent rheology, the trench and the overriding plate move self-consistently as a function of the dynamics of the system (i.e. no external forces are imposed). This setup enables to study how continental subduction influences the trench migration. We found that in all models the slab starts to advance once the continent enters the subduction zone and continues to migrate until few million years after the ultimate slab detachment. Our results support the idea that the advancing mode is favoured and, in part, provided by the intrinsic force balance of continental collision. We suggest that the advance is first induced by the locking of the subduction zone and the subsequent steepening of the slab, and next by the sinking of the deepest oceanic part of the slab, during stretching and break-off of the slab. These processes are responsible for the migration of the subduction zone by triggering small-scale convection cells in the mantle that, in turn, drag the plates. The amount of advance ranges from 40 to 220 km and depends on the dip angle of the slab before the onset of collision.

scholarly journals FAULTING DEFORMATION OF THE MESOHELLENIC TROUGH IN THE KASTORIA-NESTORION REGION (WESTERN MACEDONIA, GREECE)

2017 ◽  
Vol 43 (1) ◽  
pp. 495
Author(s):  
M. D Tranos ◽  
D.M. Mountrakis ◽  
C. B Papazachos ◽  
E. Karagianni ◽  
D. Vamvakaris
Keyword(s):  
Subduction Zone ◽  
Satellite Images ◽  
Fault Slip ◽  
Stress Inversion ◽  
Active Deformation ◽  
Hellenic Subduction Zone ◽  
Plate Deformation ◽  
Late Tertiary ◽  
Inversion Analysis ◽  
Geometry And Kinematics

The Kastoria-Nestorion region, which belongs to the Tertiary MesoHellenic Trough (MHT), is a low relief NW-SE trending intermountainous basin filled with Tertiary molasse-type sedimentary rocks and nowadays drained by the Aliakmnonas River and its tributaries. In the present work, the large fault zones in the region and the general fault pattern are defined, mapped and described with the aid of satellite images. In addition, a large number of fault-slip data from the mesoscale exposed faults has been recorded, in order to better understand the faulting geometry and kinematics of the region. The stress-inversion analysis of these fault-slip data in comparison with earthquake faultplane solution information permits us to define the stress regimes imposed to the region from the Late Tertiary up to the present and to correlate them with the late orogenic and post-orogenic deformation of the Hellenic orogen. In particular, five stress regimes have been defined from which the former two (D1 and D2) are related to the late collisional processes between the Apulia and Eurasia plates, the next two events (D3 and D4) are related to the present-day Hellenic subduction zone, whereas the last D5 event which is the active deformation of the region appears as an intra-continental or intra-plate deformation more related with the Adria-Eurasia ongoing convergence rather with the Hellenic subduction zone.

Convenient formulas for determining dip-slip fault parameters from geophysical observables

1996 ◽  
Vol 86 (5) ◽  
pp. 1642-1644 ◽  
Author(s):  
Steven C. Cohen
Keyword(s):  
Subduction Zone ◽  
Seismic Parameters ◽  
Fault Parameters ◽  
Dip Angle ◽  
Simple Equations ◽  
Angle Width ◽  
Made In

Abstract Simple equations are presented for estimating slip magnitude, fault dip angle, width of the zone of compression, and other co-seismic parameters from geologic, seismic, and geodetic observations made in subduction zone and continental dip-slip environments. These equations are easy to memorize and use without computational aids.

scholarly journals ASSESSMENT OF OPTIMUM VALUE FOR DIP ANGLE AND LOCKING RATE PARAMETERS IN MAKRAN SUBDUCTION ZONE

2017 ◽  
Vol XLII-4/W4 ◽  
pp. 523-529
Author(s):  
A. Safari ◽  
A. M. Abolghasem ◽  
N. Abedini ◽  
Z. Mousavi
Keyword(s):  
Subduction Zone ◽  
Subduction Zones ◽  
Arabian Plate ◽  
Eurasian Plate ◽  
Makran Subduction Zone ◽  
South Eastern ◽  
Best Value ◽  
Proposed Model ◽  
Sparse Measurements ◽  
Dip Angle

Makran subduction zone is one of the convergent areas that have been studied by spatial geodesy. Makran zone is located in the South Eastern of Iran and South of Pakistan forming the part of Eurasian-Arabian plate's border where oceanic crust in the Arabian plate (or in Oman Sea) subducts under the Eurasian plate ( Farhoudi and Karig, 1977). Due to lack of historical and modern tools in the area, a sampling of sparse measurements of the permanent GPS stations and temporary stations (campaign) has been conducted in the past decade. Makran subduction zone from different perspectives has unusual behaviour: For example, the Eastern and Western parts of the region have very different seismicity and also dip angle of subducted plate is in about 2 to 8 degrees that this value due to the dip angle in other subduction zone is very low. In this study, we want to find the best possible value for parameters that differs Makran subduction zone from other subduction zones. Rigid block modelling method was used to determine these parameters. From the velocity vectors calculated from GPS observations in this area, block model is formed. These observations are obtained from GPS stations that a number of them are located in South Eastern Iran and South Western Pakistan and a station located in North Eastern Oman. According to previous studies in which the locking depth of Makran subduction zone is 38km (Frohling, 2016), in the preparation of this model, parameter value of at least 38 km is considered. With this function, the amount of 2 degree value is the best value for dip angle but for the locking rate there is not any specified amount. Because the proposed model is not sensitive to this parameter. So we can not expect big earthquakes in West of Makran or a low seismicity activity in there but the proposed model definitely shows the Makran subduction layer is locked.

scholarly journals Numerical models of trench migration in continental collision zones

2012 ◽  
Vol 4 (1) ◽  
pp. 429-458 ◽  
Author(s):  
V. Magni ◽  
J. van Hunen ◽  
F. Funiciello ◽  
C. Faccenna
Keyword(s):  
Subduction Zone ◽  
Plate Tectonics ◽  
Numerical Models ◽  
Continental Collision ◽  
Force Balance ◽  
Dip Angle ◽  
External Forces ◽  
Stress Dependent ◽  
Subduction System ◽  
Intrinsic Feature

Abstract. Continental collision is an intrinsic feature of plate tectonics. The closure of an oceanic basin leads to the onset of subduction of buoyant continental material, which slows down and eventually stops the subduction process. We perform a parametric study of the geometrical and rheological influence on subduction dynamics during the subduction of continental lithosphere. In 2-D numerical models of a free subduction system with temperature and stress-dependent rheology, the trench and the overriding plate move self-consistently as a function of the dynamics of the system (i.e. no external forces are imposed). This setup enables to study how continental subduction influences the trench migration. We found that in all models the trench starts to advance once the continent enters the subduction zone and continues to migrate until few million years after the ultimate slab detachment. Our results support the idea that the trench advancing is favoured and, in part provided by, the intrinsic force balance of continental collision. We suggest that the trench advance is first induced by the locking of the subduction zone and the subsequent steepening of the slab, and next by the sinking of the deepest oceanic part of the slab, during stretching and break-off of the slab. The amount of trench advancing ranges from 40 to 220 km and depends on the dip angle of the slab before the onset of collision.

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