气候变化领域集成服务门户(CCPortal): Seismic hazard of the western Makran subduction zone: Insight from mechanical modelling and inferred frictional properties

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DOI	10.1016/j.epsl.2021.116789
	Seismic hazard of the western Makran subduction zone: Insight from mechanical modelling and inferred frictional properties
	Pajang S.; Cubas N.; Letouzey J.; Le Pourhiet L.; Seyedali S.; Fournier M.; Agard P.; Khatib M.M.; Heyhat M.; Mokhtari M.
发表日期	2021
ISSN	0012821X
卷号	562
英文摘要	Western Makran is one of the few subduction zones left with a largely unconstrained seismogenic potential. According to the sparse GPS stations, the subduction is accumulating some strain to be released during future earthquakes. To enhance the seismic hazard assessment, we here propose to study the finite deformation of the western Makran accretionary wedge. Mechanical modelling is used to retrieve the spatial variations of the frictional properties of the megathrust, and discuss its seismogenic potential. To do so, we first build a structural map along the Iranian part of the Oman Sea and investigate three N-S seismic profiles. The profiles are characterized by a long imbricated thrust zone that takes place at the front of the wedge. A diapiric zone of shallow origin lies in between the imbricated zone and the shore. Along the eastern and western shores, active listric normal faults seem to root down to the megathrust. Eastern and western domains have developed similar deformation, with three zones of active faulting: the normal faults on shore, thrusts ahead of the mud diapirs, and the frontal thrusts. On the contrary, no normal faults are identified along the central domain, where a seamount is entering into subduction. Two mechanical analyses are performed to retrieve the frictional properties of the megathrust. We first apply the critical taper theory to constrain the pore fluid pressure of the wedge. We then apply the limit analysis on two selected profiles. Along the eastern profile, a transition from very low to extremely low friction is required to activate the large coastal normal fault (μdeepeff = 0.01-0.06, μmiddleeff = 0.003-0.012). To propagate the deformation to the front, an increase of friction along the imbricated zone is necessary (μfronteff = 0.017-0.031). The method could not be applied on the incomplete western profile. However, since the deformation is similar to the eastern profile, the same transitions of friction are expected. The Central domain is also characterized by very low effective friction; but, the absence of normal fault does not allow to evidence any frictional transition. Since dynamic effective friction coefficients are significantly lower than frictions at slow slip rate, the region of extremely low friction between the normal fault and the imbricated zone might reveal the location of a seismic asperity. The difference in deformation along strike would thus reveal the existence of two different asperities, one along the eastern domain and a second along the western domain. Since no earthquake have occurred in the region for, at least, the last 1000 years, an event of large magnitude may strike the Iranian Makran, in particular the Eastern domain. © 2021 Elsevier B.V.
关键词	frictional properties Makran mechanical modelling seismic hazard
英文关键词	Deformation; Earthquakes; Friction; Hazards; Seismic response; Effective friction coefficient; Finite deformations; Frictional properties; Listric normal faults; Mechanical analysis; Mechanical modelling; Pore fluid pressure; Seismic hazard assessment; Fault slips; active fault; deformation; friction; GPS; hazard assessment; modeling; normal fault; seismic hazard; spatial variation; Arabian Sea; Indian Ocean; Makran Subduction Zone
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203246
作者单位	Geoscience department, University of Birjand, Birjand, Iran; Institut des Sciences de la Terre Paris, ISTeP UMR 7193, Sorbonne Université, CNRS-INSU, Paris, 75005, France; National Iranian Oil Company (NIOC), Tehran, Iran; International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran
推荐引用方式 GB/T 7714	Pajang S.,Cubas N.,Letouzey J.,et al. Seismic hazard of the western Makran subduction zone: Insight from mechanical modelling and inferred frictional properties[J],2021,562.
APA	Pajang S..,Cubas N..,Letouzey J..,Le Pourhiet L..,Seyedali S..,...&Mokhtari M..(2021).Seismic hazard of the western Makran subduction zone: Insight from mechanical modelling and inferred frictional properties.Earth and Planetary Science Letters,562.
MLA	Pajang S.,et al."Seismic hazard of the western Makran subduction zone: Insight from mechanical modelling and inferred frictional properties".Earth and Planetary Science Letters 562(2021).