Academic literature on the topic 'Makran subduction'

SUMMARY Neotectonic flow of the Makran subduction zone is estimated using a kinematic modelling technique based on iterated weighted least-squares that fits to all kinematic data from both geological and geophysical sources. The kinematic data set includes 87 geodetic velocities, 1962 principal stress directions, 90 fault traces, 56 geological heave rates and velocity boundary conditions. Low seismicity of western Makran compared to its eastern part, may indicate that either the subduction interface is currently locked, accumulating elastic strain or aseismic slip (creep) occurs along this part of the plate boundary. Therefore, we define two different models to evaluate the possibility of creep in the western Makran. Models define a locked subduction zone versus a steady creeping subduction for the western Makran. The locking depth of the subducting fault is also investigated, and a locking between 14 and 40–45 km depth provided the best consistency with geodetic observations. The 2 kinematic models provide long-term fault slip rates. The models estimated the shortening rate of 16.6–22.5 mm yr−1 and the strike-slip movement of 0.2–6.0 mm yr−1 for six segments along the subduction fault. The steady creeping subduction model predicts a 1–2 mm yr−1 lower shortening rate than the locked model for the Makran subduction fault (MSF). To verify the results, the estimated fault slip rates are compared to slip rates based on the geodetical and geological studies, which have not been used as model inputs. Our estimated rates fall within the range of geodetic rates and are even more consistent with geological rates than previous GPS-based estimates. In addition, the model provides the long-term velocity, and distributed permanent strain rates in the region. Based on the SHIFT hypotheses, long-term seismicity rates are computed for both models based on the estimated strain rate. These maps were compared with seismic catalogues. The estimated seismicity rate for the western part of Makran from the creeping subduction model is more compatible with the observation. The results of two deformation models lead us to a coupling ratio of ∼0.1 for the western MSF.

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.

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.

The uncertain tsunamigenic potential of the Makran Subduction Zone (MSZ) has made it an interesting natural laboratory for tsunami-related studies. This study aims to review the recent activities on tsunami hazard in the Makran subduction zone with a focus on deterministic and probabilistic tsunami hazard assessments. While almost all studies focused on tsunami hazard from the Makran subduction thrust, other local sources such as splay faults and landslides can be also real threats in the future. Far-field tsunami sources such as Sumatra-Andaman and Java subduction zones, commonly lumped as the Sunda subduction zone, do not seem to pose a serious risk to the Makran coastlines. The tsunamigenic potential of the western segment of the MSZ should not be underestimated considering the new evidence from geological studies and lessons from past tsunamis in the world. An overview of the results of tsunami hazard studies shows that the coastal area between Kereti to Ormara along the shoreline of Iran-Pakistan and the coastal segment between Muscat and Sur along Oman’s shoreline are the most hazardous areas. Uncertainties in studying tsunami hazard for the Makran region are large. We recommend that future studies mainly focus on the role of thick sediments, a better understanding of the plates interface geometry, the source mechanism and history of extreme-wave deposits, the contribution of other local tsunamigenic sources and vulnerability assessment for all coastlines of the whole Makran region.

Abstract. The towns of Pasni and Ormara were the most severely affected by the 1945 Makran tsunami. The water inundated land for almost 1 km at Pasni, engulfing 80 % of the huts of the town, while at Ormara the tsunami inundated land for 2.5 km, washing away 60 % of the huts. The plate boundary between the Arabian Plate and Eurasian Plate is marked by Makran subduction zone (MSZ). This Makran subduction zone in November 1945 was the source of a great earthquake (8.1 Mw) and an associated tsunami. Estimated death tolls, waves arrival times, and the extent of inundation and runup have remained vague. We summarize observations of the tsunami through newspaper items, eyewitness accounts and archival documents. The information gathered is reviewed and quantified where possible to obtain the inundation parameters specifically and understand the impact in general along the Makran coast. The quantification of runup and inundation extents is based on a field survey or old maps.

The long-term pattern of severe incidents is one of the most crucial and fascinating topics of seismic events. This work aims to analyze the maximum annual earthquake magnitude in the Makran subduction zone using extreme value theory by implementing the block maxima method. The seismic data utilized for the current study was collected from the International Seismological Center (ISC) ranging from 1934 to 2022. The extreme parameters have fitted utilizing the generalized extreme value distribution. Numerous plots of the generalized extreme value distribution approach gave the accuracy of the used model when fitted to seismic data of the Makran subduction zone. Using the profile likelihood approach, the shape parameters (?) calculated is 0.29. According to the model fit, the Fréchet distribution is the best model for predicting the annual maximum earthquake magnitude in the Makran subduction zone. The estimated return levels for different return periods 10, 20, 50, and 100 are 6.35, 6.81, 7.58, and 8.31, respectively, indicating that an earthquake's maximum magnitude is increasing across the future 100 years. We also computed the profile likelihood to achieve a precise confidence interval. Thus, the 1945 earthquake of the Makran region with magnitude 8.1(Mw) was one of the most significant events in this area and occurred once every 100 years. The significance of this research is to inform decision-makers to implement suitable risk-mitigation methods.

Makran Subduction Zone (MZS) is important as this region lies on both sides of the border of Iran and Pakistan along the coastline. Makran Subduction complex has pervasive seismicity and diverse focal mechanism solutions and being in the vicinity of Triple Junction where three major Tectonic plates; Arabian, Eurasian and Indian plates are connecting. Both of Chabahar and Gwadar ports are located in this vicinity, on which China is investing for CPEC, Belt and Road Initiative. The whole world is looking at these projects of Makran, as this may define and transform the future of trade. Hence Geoscience point of view is notable as well in consideration for the successful execution of these projects. Several Microplates/blocks have been proposed around the vicinity MSZ and Indian-Eurasian Plate boundary including the Ormara microplate, Lut Block, Helmand Block, and Pakistan-Iran Makran microplate (PIMM). The purpose of this review is to shed light on PIMM. Despite previous researches related to Makran, still many researchers are working to solve puzzles related to the complexity of MSZ. It is divided into Eastern and Western Makran due to seismicity and North to South into four parts based on stratigraphy, thrusts and folds. This review aims to give suggestions for the hypothesis on PIMM which was inferred as a separate microplate.

Earthquake is the most lethal type of natural disaster. Researchers have been working to develop precise earthquake prediction methods to save lives. A statistical investigation is an effective earthquake prediction method because they offer more details about the seismic risk or hazard issue. This study utilizes seismic data from the Makran subduction zone from 1934 to 2017. Probability distributions may be employed to assess the risk of seismic events and earthquake occurrence probability. This work estimates the probability of the next major event in the Makran subduction zone through Weibull distribution by considering strong earthquakes with a magnitude (Mw ≥ 6) in the intervals (in years) between two consecutive earthquakes. The probabilities of the forthcoming seismic event have been estimated based on the previous earthquake record, pictorially. The calculated parameters of the Weibull distribution for the Makran subduction zone may help to forecast the probabilities of a strong earthquake and describe the pattern of earthquake average return time. The calculated probability for the Weibull distribution reaches 0.92 after ten years since the last strong earthquake in 2021, indicating that the Weibull distribution within and around the present research area in 2031 will be 92%.

Le complexe de subduction de Makran, au nord de la mer d’Arabie, à développé un vaste prisme d’accrétion en réponse à la subduction de la plaque Arabe sous la plaque Eurasie. Les différentes campagnes océanographiques, menées au large du Pakistan, ont révélé la morphologie et la configuration des structures des plaques plongeante et chevauchante. A partir du nouveau jeu de données acquis en 2004, j’évalue les implications des structures de la plaque plongeante sur la déformation dans le prisme mais également sur la cinématique de la région. Par ailleurs, grâce à la couverture quasiment continue des données, j’ai pu étudier dans un deuxième volet la dispersion des sédiments sur le prisme et dans la fosse du Makran.

La zone de subduction du Makran, situé entre les plaques Arabe, Indienne et Eurasienne est caractérisé par l’un des plus grands prisme d’accrétion au monde. D’âge cénozoïque, ce prisme présente de fortes différences dans sa morphologie d’Est en Ouest, à terre et en mer. Afin de déterminer les causes de ces disparités, des données de sismiques réflexion ont été étudiés en mer à travers le prisme et le Golfe d’Oman, nous renseignant sur l’évolution de la zone d’étude à l’échelle du bassin. Des données de tomographie sismique ont aussi été étudiés à travers la région, nous renseignant sur la structure lithosphérique de la zone de subduction. Les résultats montrent que la structure du prisme en mer est régie par la dynamique sédimentaire Plio-Pléistocène du prisme, lié à sa cannibalisation. Le secteur occidental du prisme montre une accumulation préférentielle de sédiments dans la plateforme, alors qu’un système turbiditique permet l’acheminement de sédiments à la fosse dans le secteur oriental. La structure profonde de la zone de subduction est caractérisée par un premier panneau plongeant lié à la plaque Arabe, affecté par une déchirure subhorizontale dans la partie ouest de la zone de subduction. Cette déchirure se situe à l’ouest d’une zone de transfert majeur identifié sur la marge Omanaise, indiquant une possible segmentation de la plaque subduite. Cette déchirure est potentiellement responsable de la formation d’un olistostrome dans la partie occidentale du prisme, qui est responsable de la morphologie distincte du prisme émergé dans ce secteur. Un deuxième panneau plongeant, associé à la plaque indienne, est situé dans la partie la plus à l’Est de la subduction
The Makran subduction zone, located between the Arabian, Indian and Eurasian plates, is characterized by one of the largest accretionary prism of the world. This Cenozoic prism shows stark morphological differences from East to West, onshore and offshore. To assess the causes for these differences, offshore multichannel seismic data has been studied throughout the prism and the Gulf of Oman, allowing us to assess the evolution of the study area at the basin scale. Seismic tomography data was also studied across the region, providing insights into the subduction zone's lithospheric structure. The results show that the structure of the offshore prism is partly linked to Plio-Pleistocene surface processes due to its reworking. The western sector of the prism shows mainly a large accumulation of sediments in the shelf, compared to the eastern sector, where sediments are also routed to the trench by a turbiditic system. The deep structure of the subduction zone is characterized by a first subducting plate related to the Arabian plate, affected by a sub-horizontal tear. This tear is located west of a major transfer zone identified on the northern Oman margin, indicating a possible segmentation of the subducting plate. This tear may be responsible for forming a major olistostrome, which impacts the morphology of the onshore wedge. An additional subducting plate, related to the Indian plate, is located in the easternmost sector of the subduction zone

The Makran subduction zone (offshore Pakistan and Iran) has the largest accretionary prism of any margin worldwide, formed due to the thick incoming sediment section of up to 7.5 km. This margin has been relatively understudied, and this thesis presents a new, detailed structural and hydrological interpretation and seismogenic hazard assessment for the Makran. The accretionary prism is dominated by simple, imbricate thrusts which form seaward verging, anticlinal ridges up to 200 km long. The prism has a low average taper angle of 4.5°. Two oceanic basement features intersect the deformation front: The Little Murray Ridge (LMR), a discontinuous, largely buried seamount chain, and the Murray Ridge, a large transtensional ridge. The subduction of the LMR causes an increase in fault spacing, a seaward step in the position of the deformation front, and may segment earthquake rupture. The Murray Ridge influences the incoming sediment stratigraphy and reduces sediment thickness in the east. Fault activity in the Makran is widely distributed within the prism, with over 75% of faults showing some evidence for recent activity. This may be the result of the high levels of frontal accretion causing the Makran to behave as a sub-critical prism. The décollement in the outer prism occurs within the sediment section and is unreflective. There is extensive evidence for fluid and fluid migration in the Makran, with a widespread hydrate BSR, high amplitude gas zones in the shallow sediment, reflective fault sections (indicating high porosity and likely high pore pressure), and surface seeps. The spatial distribution of these features appears to be controlled by changes in the incoming section and fault activity, and significant fluids are trapped within anticlinal hinge zones. Reflective fault sections are concentrated in the upper sediments, and there is no evidence for a significant fluid contribution from the deeper (>4 km) sediment section. This may indicate that the lower sediment section is largely dehydrated, prior to accretion. The Makran experiences low seismicity compared to many global subduction zones, but produced a Mw8.1 tsunamigenic earthquake in 1945. Thermal modelling suggests that temperatures at the plate boundary are over 150°C at the deformation front due to the thick sediment section. These results suggest that the plate boundary may have the potential to be seismogenic to shallow depths. Thermal modelling also indicates that the shallow dip of the subducting plate produces a wide potential seismogenic zone, which when combined with along-strike rupture scenarios produces potential earthquake magnitudes of Mw8.7-9.2 with significant regional hazard implications.

Les données GPS indiquent que la subduction accumule des contraintes qui devraient être libérées lors de futurs séismes, Makran potentiel sismogénique est très mal contraint. J’ai d’abord construit une carte structurale le long de la partie iranienne de la mer d'Oman. Ensuite, j’ai contraint la pression de fluide interstitiel et les propriétés de friction du prisme à partir de la théorie du prisme critique et de l'analyse limite. Les résultats montrent que le long des profils Est et Ouest, une transition d'une friction très faible à une friction extrêmement faible est nécessaire pour activer la grande faille normale côtière. Pour propager la déformation vers le front, une augmentation de la friction le long de la zone imbriquée est necessaire. Les modèles Makran sont calibrés les paramètres thermiques et les conditions aux limites des simulations à l'aide de la profondeur des réflecteurs du plancher océanique et du fond marin et des quelques données de puits disponibles. En considérant deux décollements: -le sous-plaquage est associé à une déformation visqueuse, -la déshydratation et la transition smectite/illite permettent de produire des segments à trois pentes comme observés dans les prismes. -la subduction d'un grand mont sous-marin est accompagnée de grandes failles normales. Dans le cas d’un comportement sismogénique du décollement, la limite inférieure de la zone sismogénique correspondra au début du sous-plaquage. En supposant que la limite supérieure des aspérités sismiques soit corrélée à la transition smectite-illite, une aspérité sismique peut donc s'étendre de cette transition, jusqu'au début du sous-plaquage, et correspondre à une topographie relativement plate
Makran has a largely unconstrained seismogenic potential although GPS data indicate the subduction is accumulating some strain to be released during future earthquakes. I first build a structural map along the Iranian part of the Oman Sea which indicates three segments. Then, I retrieve the pore fluid pressure and the frictional properties of the wedge with the critical taper theory and the limit analysis. The results show that along the eastern and western profiles, a transition from very low to extremely low friction is required to activate the large coastal normal fault. To propagate the deformation to the front, an increase of friction along the imbricated zone is necessary.The Makran Models are calibrated the thermal parameters and boundary conditions of the numerical simulations using seafloor and bottom sea reflector depth and few available well data. Considering two décollements, the results show that, -underplating is associated to viscous deformation -dewatering and smectite/illite transition permit to produce three slope segments observed in accretionary prisms but this friction drop is not sufficient for formation of normal faults. - the subduction of a large seamount is accompanied by large normal faults, while their location migrates through time. If the brittle décollements have a seismogenic behavior, the down-dip limit of the seismogenic zone will correspond to the onset of underplating. By assuming that the up-dip limit of seismic asperities correlates with smectite-illite transition, then a seismic asperity may extend from this transition, down to the onset of underplating, and correlate with a relatively flat topography
منشور برافزايشي مكران به راحتي در دسترس نيست، بنابراين و بويژه در بخش خشكي به خوبي موردبررسي قرار نگرفته است. پتانسيل لرزه اي مكران به درستي شناسايي نشده است. اين در حالي است كه دادههاي جي پي اس تجمع استرين را نشان مي دهد كه در طول زلزله هاي محتمل آتي آزاد شود. در اينجامطالعه دگرشكلي غرب منشور برافزايشي مكران بر پايه ي داده هاي ساختاري جديد، پروفيل هاي لرزه اي بههمراه پروفيل هاي توموگرافي پيشنهاد شده است. اين رساله با به كارگيري مدل سازي مكانيكي وترمومكانيكي، تكامل ساختاري منطقه و تحليل خطر لرزه اي در امتداد سه سكشن دريايي و دو سكشنخشكي در مقياس پوسته اي را مطرح كرده است.( ابتدا نقشه ساختاري در امتداد قسمت ايراني درياي عمان تهيه گرديد كه نشانگر سه بخش است؛ ( ١منطقه راندگي همپوشان در قسمت پيشاني؛ ( ٢) منطقه دياپيري با منشا كم عمق در بين منطقه راندگيهمپوشان و ساحل؛ ( ٣) گسل هاي نرمال فعال در قسمت هاي شرقي و غربي منطقه كه به نظر ميرسند ازلايه ديتچمنت ريشه گرفته اند. در مقابل گسل نرمال در امتداد قسمت مركزي جايي كه كوه دريايي واردفرورانش ميشود، شناسايي نشد. سپس فشار سيالات منفذي و مشخصات اصطكاكي گوه بر طبق تئوري گوههاي بحراني و آناليز محدود بدست آمد. نتايج نشان مي دهد براي فعال شدن گسل نرمال كاهش اصطكاك از٠,٠٠٣ ) در امتداد پروفيل شرقي و غربي لازم است. براي انتشار - ٠,٠٦ ) به ناچيز ( ٠,٠١٢ - مقادير كم ( ٠,٠١٠,٠٣١ ) ضروري است. - دگرشكلي به جلو، افزايش اصطكاك در امتداد منطقه راندگي همپوشان ( ٠,٠١٧شيب توپوگرافي بسيار كم متناسب با مقدار اصطكاك ناچيز ميتواند به عنوان منطقه قفل شده لرزه اي درطول تراست اصلي، كه به صورت اپيزودي با نرخ لغزش ديناميكي دگرشكل شده، يا رفتار خزش شكل پذيرديتچمنت تفسير شود. براي مطالعه انتقال رفتار شكننده- ويسكوز بر شيب توپوگرافي و دگرشكلي، مدل سازيدو بعدي ترمومكانيكي با ثابت كردن جريان حرارتي در انتهاي مدل كه منجر به افزايش دما با افزايش عمقمي شود، انجام گرفت. ابتدا شبيه سازي هاي ساده در جهت بررسي تاثير جريان حرارتي كف، گرمايش برشي،روپوشش دمايي رسوبات و ضخامت رسوبات ثانويه انجام شد. نتايج نشان دهنده سه بخش متناسب با سه رفتاردگرشكلي متفاوت است؛ ( ١) گوه كاملا شكننده با شيب توپوگرافي ثابت پيش بيني شده با تئوري گوه هايبحراني در بخش جلويي؛ ( ٢) نشيب بسيار ناچيز به همراه ديتچمنت و توالي ويسكوز، نزديك به حصار پايانيمدل؛ و ( ٣) در ميان اين دو، افزايش محلي نشيب به عنوان مشخصه انتقال شكننده- ويسكوز همراه باديتچمنت شكننده و دگرشكلي ويسكوز. هيچ يك از اين مدل ها منجر به شكل گير گسل نرمال نشد.براي بازسازي ويژگي هاي مكران، پيچيدگي مدل افزايش يافت و مشخصه هاي دمايي و شرايط مرزيكف دريا و داده ي چاه سنجيده شد. با در نظر گرفتن دو لايه ديتچمنت ،bsr مدل با استفاده از عمق بازتابندهنتايج بيان ميكند كه:١- زير راندگي متناسب با دگرشكلي ويسكوز است.٢- آبدهي و انتقال اسمكتيت- ايليت منجر به شكل گيري سه توپوگرافي متفاوت مشاهده شده در گوههاي برافزايشي مي شود اما اين كاهش اصطكاك براي شكل گيري گسل نرمال كافي نيست.٣- فرورانش كوه دريايي با شكل گيري گسل هاي نرمال بزرگ همراه است، در حالي كه مكان آنها درطول زمان تغيير مي كند.اگر ديتچمت شكننده رفتار لرزه اي داشته باشد، حد پاييني منطقه لرزه زا با شروع زيرراندگي تطابقخواهد داشت. با فرض كنترل حد بالايي منطقه لرزه زا با انتقال اسمكتيت- ايليت، پس پتانسيل لرزه اي ازاين انتقال تا شروع زيرراندگي كه معرف توپوگرافي مسطح است، گسترش مي يابد. اين مكان سازگار با مدلمحل وقوع زلزله ٨,١ ريشتري ١٩٤٥ پاكستان و پيشينه ي كم عمق لرزه اي در امتداد خشكي ،gps سازيو بخش شكننده راندگي ها و نه در امتداد عميق ساختاري است.در طول پروفيل شرقي، اگرچه شكل گيري گسل نرمال ممكن است مرتبط با زيرراندگي يا فرورانش كوهدريايي باشد، گسل نرمال در حال حاضر در بالاي منطقه زيرراندگي درنتيجه انتقال شكننده - ويسكوز قرارگرفته است.پروفيل مركزي نشان دهنده دوپلكس هاي عميق در مناطق ساحلي و با حضور زون دياپيري طويل است.از آنجايي كه توپوگرافي مسطح و محل گل فشان ها احتمالا آشكار كننده پنجره انتقالي اسمكتيت- ايليتاست، اگر اين پنجره معرف زون لرزه زا باشد، اين منطقه نيز پتانسيل لرزه زايي دارد. به هر صورت اين مناطقبا پتانسيل لرزه زايي وسعت كمي دارند و بزرگاي زلزله فقط به گسترش جانبي آن بستگي دارد

Les transitions spatiale et temporelle de la subduction à la collision sont des charnières géodynamiques. Nous précisons dans ce travail le rôle et le devenir de ces zones grâce à des modèles analogiques et l'étude tectonique d'un cas réel. La modélisation a montré qu'une transition temporelle entre subduction et collision est toujours marquée par une phase de subduction continentale. La durée de cette phase dépend de la façon dont se déforme la lithosphère subductée en profondeur. Plus elle se déforme, plus courte est la subduction continentale. Dans le cas d'une transition latérale entre subduction et collision, la déformation de la plaque supérieure est aussi fonction de sa résistance à la déformation et notamment de l'existence de zones de faiblesse. Notre analyse tectonique montre que la déformation actuelle à la transition Zagros-Makran (SE Iran) est distribuée sur un large domaine, au niveau de deux systèmes de failles, d'orientation N 160° et N 0°. Le régime est globalement transpressif, et montre deux phases distinctes. 1-Mio-Pliocène : failles inverses avec un probable partitionnement avec des plis. 2-Plio-Quaternaire : déformation purement cassante, avec une contrainte principale horizontale, s1, de direction NE-SO, homogène sur toute la zone. L'analyse de marqueurs géomorphologiques décalés et datés (datations 10Be, et corrélations paléoclimatiques et archéologiques), nous a permis de déterminer les vitesses de déplacement de chaque faille et d'obtenir le déplacement total sur la zone, de 12±2 mm/a dans une direction environ ~10°. La distribution de la déformation montrée par la tectonique peut être attribuée à la prolongation du slab du Makran sous le Zagros, et montre, comme la modélisation, à quel point la déformation de surface est tributaire de processus profonds. La déformation en Iran comme celle des modèles montre de plus une forte localisation de la déformation par des zones de faiblesse héritées de l'histoire géologique régionale.

The 2004 Indian Ocean tsunami which exported death and destruction to far distant shores, once more emphasized the tsunami hazards associated with transoceanic tsunamis. Historical records of tsunamis in the Makran subduction zone (MSZ) reveal that Makran tsunamis are capable of producing large waves in the far-field. The Makran tsunami of 1945 produced by an Mw8.1 earthquake was reported to cause far-field effects in the Indian Ocean and reached a height of about 30 cm in the Seychelles, at the distance of about 3500 km from the MSZ. Here, we assess historical observations of this event and perform numerical modeling of this tsunami with emphasis on its far-field effects. Our numerical modeling successfully reproduces most feathers of the historical observations including its far-field effects. Southward propagation of Makran large tsunamis is investigated and their possible effects on Maldives and Seychelles islands are discussed. This study will help to better understand tsunami hazard associated with the MSZ, especially its far-field hazard.

The extensive death toll and sever economical damages brought by the 2004 Indian Ocean tsunami has emphasized the urgent need for assessing the hazard of tsunami in this ocean, and determining the most vulnerable coastlines to the impact of possible tsunami. In this paper the hazard of tsunami for southern coasts of Iran bordering the Indian Ocean is discussed. At first, historical data of tsunami occurrences on the Iranian southern coasts are collected, described and analyzed. Then, numerical simulation of potential tsunamis in the Makran subduction zone is performed and the tsunami wave height distribution along the Iranian coast is calculated. The Makran subduction zone is among two main tsunamigenic zones in the Indian Ocean. In this zone the Oman oceanic plate subducts beneath the Iranian Micro-plate at an estimated rate of about 19 mm/yr. Historically, there is the potential for tsunami generation in this region and several tsunamis attacked the Makran coastlines in the past. The most recent tsunami in this region has occurred on 28 November 1945 which took the lives of more than 4000 people in the coasts of Iran, Pakistan, India, and Oman. Here we examine the seafloor uplift of the Makran zone and its potential for generating destructive tsunamis in the southern coastlines of Iran. Several earthquake scenarios with moment magnitudes ranging between 6.5 and 8.5 are used as initial conditions for analysis. For scenario of an earthquake with magnitude of 8.0, propagation of tsunami waves on coastlines and wave time histories in selected reference locations are calculated.