scholarly journals Megathrust and accretionary wedge properties and behaviour in the Makran subduction zone

2017 ◽  
Vol 209 (3) ◽  
pp. 1800-1830 ◽  
Author(s):  
Camilla Penney ◽  
Farokh Tavakoli ◽  
Abdolreza Saadat ◽  
Hamid Reza Nankali ◽  
Morteza Sedighi ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Accretionary Wedge ◽  
Makran Subduction Zone

scholarly journals A review of the seismotectonics of the Makran Subduction Zone as a baseline for Tsunami Hazard Assessments

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Mohammad Mokhtari ◽  
Ahmad Ala Amjadi ◽  
Leila Mahshadnia ◽  
Mandana Rafizadeh
Keyword(s):  
Subduction Zone ◽  
Tectonic Setting ◽  
Accretionary Prism ◽  
Tsunami Hazard ◽  
Indian Plate ◽  
Arabian Plate ◽  
Accretionary Wedge ◽  
The West ◽  
Makran Subduction Zone ◽  
Velocity Models

Abstract The Makran Accretionary Wedge (900 km across) is a consequence of northward subduction of the oceanic part of the Arabian Plate beneath the Lut and Afghan blocks in the northwestern Indian Ocean. It has a complicated tectonic setting as it is located at a triple junction with the Indian Plate. Thick sedimentary layers, a shallow angle of the subducting slab and a large width of the subduction zone, ca. 500–600 km from volcanic arc to active wedge front, are some of the foremost and distinctive characteristics of the Makran Subduction Zone (MSZ). The MSZ is likely divided into at least two segments: the west and the east possibly separated by a sinistral fault known as the Sonne Fault. A division is also inferred from seismicity as it is higher in the east when compared to the west. With the exception of a notable trench, all other characteristics of an accretionary prism observed in well-studied subduction zone can be identified or inferred in the Makran. Three long seismic profiles of the western Makran (200 km long each, with shot points interval of 20 km and receivers interval of 700 m) have recently been acquired. Using these datasets, improved structural/velocity models for the western Makran were developed. This review aims to contribute to achieving a better understanding of the seismotectonic setting and dynamics of the Makran Subduction Zone as it feeds to a refined understanding of the tsunami hazard in the region.

Anatomy of a crustal-scale accretionary complex: Insights from deep seismic sounding of the onshore western Makran subduction zone, Iran

Geology ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 3-7 ◽  
Author(s):  
Christian Haberland ◽  
Mohammad Mokhtari ◽  
Hassan Ali Babaei ◽  
Trond Ryberg ◽  
Mehdi Masoodi ◽  
...  
Keyword(s):  
Subduction Zone ◽  
P Wave ◽  
Deep Seismic Sounding ◽  
Accretionary Wedge ◽  
Makran Subduction Zone ◽  
Line Drawings ◽  
Seismic Sounding ◽  
Surface Geology ◽  
Shallow Structure ◽  
Shed Light

Abstract The Makran subduction zone has produced M 8+ earthquakes and subsequent tsunamis in historic times, hence indicating high risk for the coastal regions of southern Iran, Pakistan, and neighboring countries. Besides this, the Makran subduction zone is an end-member subduction zone featuring extreme properties, with one of the largest sediment inputs and the widest accretionary wedge on Earth. While surface geology and shallow structure of the offshore wedge have been relatively well studied, primary information on the deeper structure of the onshore part is largely absent. We present three crustal-scale, trench-perpendicular, deep seismic sounding profiles crossing the subaerial part of the accretionary wedge of the western Makran subduction zone in Iran. P-wave travel-time tomography based on a Monte Carlo Markov chain algorithm as well as the migration of automatic line drawings of wide-angle reflections reveal the crustal structure of the wedge and geometry of the subducting oceanic plate at high resolution. The images shed light on the accretionary processes, in particular the generation of continental crust by basal accretion, and provide vital basic information for hazard assessment and tsunami modeling.

scholarly journals New high-resolution 2D seismic imaging of fluid escape structures in the Makran subduction zone

China Geology ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 1-14
Author(s):  
Bin Liu ◽  
◽  
Jiang-xin Chen ◽  
Syed Waseem Haider ◽  
Xi-guang Deng ◽  
...  
Keyword(s):  
High Resolution ◽  
Subduction Zone ◽  
Seismic Imaging ◽  
Makran Subduction Zone

Structure of the Makran subduction zone from wide-angle and reflection seismic data

2000 ◽  
Vol 329 (1-4) ◽  
pp. 171-191 ◽  
Author(s):  
C. Kopp ◽  
J. Fruehn ◽  
E.R. Flueh ◽  
C. Reichert ◽  
N. Kukowski ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Seismic Data ◽  
Wide Angle ◽  
Makran Subduction Zone ◽  
Reflection Seismic

scholarly journals Dating and morpho-stratigraphy of uplifted marine terraces in the Makran subduction zone (Iran)

2019 ◽  
Vol 7 (1) ◽  
pp. 321-344 ◽  
Author(s):  
Raphaël Normand ◽  
Guy Simpson ◽  
Frédéric Herman ◽  
Rabiul Haque Biswas ◽  
Abbas Bahroudi ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Active Surface ◽  
Optically Stimulated Luminescence ◽  
Uplift Rate ◽  
Makran Subduction Zone ◽  
Megathrust Earthquakes ◽  
Surface Uplift ◽  
Marine Terraces ◽  
Uplift Rates ◽  
East West

Abstract. The western part of the Makran subduction zone (Iran) is currently experiencing active surface uplift, as attested by the presence of emerged marine terraces along the coast. To better understand the uplift recorded by these terraces, we investigated seven localities along the Iranian Makran and we performed radiocarbon, 230Th∕U and optically stimulated luminescence (OSL) dating of the layers of marine sediments deposited on top of the terraces. This enabled us to correlate the terraces regionally and to assign them to different Quaternary sea-level highstands. Our results show east–west variations in surface uplift rates mostly between 0.05 and 1.2 mm yr−1. We detected a region of anomalously high uplift rate, where two MIS 3 terraces are emerged, but we are uncertain how to interpret these results in a geologically coherent context. Although it is presently not clear whether the uplift of the terraces is linked to the occurrence of large megathrust earthquakes, our results highlight rapid surface uplift for a subduction zone context and heterogeneous accumulation of deformation in the overriding plate.

scholarly journals Dating and morphostratigraphy of uplifted marine terraces in the Makran subduction zone (Iran)

2018 ◽  
Author(s):  
Raphaël Normand ◽  
Guy Simpson ◽  
Frédéric Herman ◽  
Rabiul Haque Biswas ◽  
Abbas Bahroudi ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Surface Deformation ◽  
Late Quaternary ◽  
Makran Subduction Zone ◽  
Megathrust Earthquakes ◽  
Surface Uplift ◽  
Marine Terraces ◽  
Uplift Rates ◽  
Tectonically Active ◽  
East West

Abstract. The western part of the Makran subduction zone (Iran) has not experienced a great megathrust earthquake in recent human history, yet, the presence of emerged marine terraces along the coast indicates that the margin has been tectonically active during at least the late Quaternary. To better understand the surface deformation of this region, we mapped the terraces sequences of seven localities along the Iranian Makran. Additionnaly, we performed radiocarbon, 230Th/U and optically stimulated luminescence (OSL) dating of the layers of marine sediments deposited on top of the terraces. This enabled us to correlate the terraces regionally and to assign them to different Quaternary sea level highstands. Our results show east-west variations in surface uplift rates mostly between 0.05 and 1.2 mm y−1. We detected a region of anomalously high uplift rate, where two MIS 3 terraces are emerged, yet we are uncertain how to insert these results in a geologically coherent context. Although it is presently not clear whether the uplift of the terraces is linked with the occurrence of large megathrust earthquakes, our results highlight heterogeneous accumulation of deformation in the overriding plate.

Subduction processes on the Mariana trench and northern Manila trench: implications for the intra-oceanic and ocean-continent convergent margins

2020 ◽  
Author(s):  
Yang Liu ◽  
Ziyin Wu ◽  
Jihong Shang ◽  
Dineng Zhao ◽  
Jieqiong Zhou
Keyword(s):  
Subduction Zone ◽  
Comparative Investigation ◽  
Accretionary Wedge ◽  
Convergent Margins ◽  
Seismic Profiles ◽  
Seafloor Morphology ◽  
Bathymetric Data ◽  
Manila Trench ◽  
Subduction Erosion ◽  
Material Transportation

<p>Different tectonic backgrounds often produce different subduction mechanisms. The Mariana subduction zone is a typical erosive margin, and the mode of material transportation is mainly controlled by subduction erosion, while the subduction process in the northern Manila subduction zone is dominated by subduction accretion. However, there are little comparative investigation about the subduction mechanisms between the Mariana subduction zone and northern Manila subduction zone. In this study, the high-resolution bathymetric data obtained by using the multi-source data fusion method and collected multichannel seismic profiles are used to research the subduction mechanisms and to develop the subduction modes for the Mariana subduction zone and northern Manila subduction zone. We propose that the Mariana subduction zone formed at the intra-oceanic convergent margins with rare continental sediments tends to occur subduction erosion. A rough seafloor morphology (e.g. seamounts, horst and graben topography) of the subducting Pacific Plate, with a convergence rate of 8.4 cm/yr, and the steep slope of the inner trench, promote subduction erosion at the Mariana margin. The northern Manila subduction zone is the result of the convergence of ocean-continent plates. The continental sediments of the overlying plate usually undergo subduction accretion during the subducting process, forming an accretionary wedge along the northern Manila margin. With the continuously subducting of the continental crust, a series of folds and thrust faults are formed inside the accretionary wedge. Both the Mariana subduction zone and northern Manila subduction zone are distinctive types of the convergent margins in the world. The comparison of subduction mechanisms has important reference significance for the study of the subduction process, evolution and inter-plate interaction of global intra-oceanic and ocean-continent convergent margins.</p><p></p>

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