Tectonics最新文献_第10页

Tectonic Evolution of a Sedimented Oceanic Transform Fault: The Owen Transform Fault, Indian Ocean 沉积海洋转换断层的构造演化:印度洋欧文转换断层

IF 4.2 1区地球科学

Tectonics Pub Date : 2023-04-30 DOI: 10.1029/2023TC007747

A. Janin, N. Chamot‐Rooke, M. Delescluse, M. Fournier, J. Olive, A. Rabaute, P. Huchon, J. Dyment, C. Vigny, Mathieu Rodriguez

{"title":"Tectonic Evolution of a Sedimented Oceanic Transform Fault: The Owen Transform Fault, Indian Ocean","authors":"A. Janin, N. Chamot‐Rooke, M. Delescluse, M. Fournier, J. Olive, A. Rabaute, P. Huchon, J. Dyment, C. Vigny, Mathieu Rodriguez","doi":"10.1029/2023TC007747","DOIUrl":"https://doi.org/10.1029/2023TC007747","url":null,"abstract":"The Owen transform fault (OTF) connecting the Sheba and the Carlsberg spreading ridges in the Indian Ocean currently forms the active plate boundary between India and Somalia plates. This 330‐km‐long transform fault is by far the longest transform fault along the India‐Somalia plate boundary and its valley is buried under the thick distal turbidites of the Indus Fan with total thickness ranging from 1,000 to >5,000 m. A new set of seismic reflection and multibeam bathymetric data reveals remarkable transpressive structures along its entire length recorded as folds in the sedimentary cover, eruption of mud ridges at the seafloor, thrusts in the young oceanic lithosphere. Based on a new regional time‐calibration of the seismic reflectors, we show that sediments in the transform valley (post 8.6 Ma) recorded a period of tectonic quiescence until the onset of a transpressive event around 1.5–2.4 Ma that we relate to a minor change in India‐Somalia kinematics not captured by magnetic anomalies. This tectonic regime is still active based on compressive earthquakes and deformation of the most recent sediments. Transpression resulted in the formation of a proto‐median ridge and the coeval propagation of the tip of the Carlsberg Ridge into the Somalian plate. These features are typically encountered at many other transform faults but rarely captured in their very early stage.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44388437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Paleomagnetic Evidence for Pre‐21 Ma Independent Drift of South Sardinia From North Sardinia‐Corsica: “Greater Iberia” Versus Europe 从北撒丁岛到科西嘉岛的南撒丁岛21 Ma前独立漂移的古地磁证据：“大伊比利亚”与欧洲

IF 4.2 1区地球科学

Tectonics Pub Date : 2023-04-28 DOI: 10.1029/2022TC007705

G. Siravo, F. Speranza, M. Mattei

{"title":"Paleomagnetic Evidence for Pre‐21 Ma Independent Drift of South Sardinia From North Sardinia‐Corsica: “Greater Iberia” Versus Europe","authors":"G. Siravo, F. Speranza, M. Mattei","doi":"10.1029/2022TC007705","DOIUrl":"https://doi.org/10.1029/2022TC007705","url":null,"abstract":"It is unanimously acknowledged that the Corsica‐Sardinia microplate rotated counterclockwise (CCW) by 40–50° between 21 and 15 Ma, synchronous with Liguro‐Provençal Basin oceanic spreading. Conversely, 60–120° CCW rotations with respect to Europe from Sardinia (Permian dykes, volcanics and sediments, Mesozoic carbonates, and lower Eocene limestones) have been interpreted to be related to (a) late Permian intra‐Pangea shear events, (b) Aptian Iberia rotation, and (c) Eocene Valais Ocean closure. We report paleomagnetic data from 31 red‐bed sites from the mid‐late Eocene (45–32 Ma) Cixerri Fm. exposed in SW Sardinia. Characteristic paleomagnetic directions from 25 dual polarity sites (240 samples) define an 86 ± 7° CCW rotation. We suggest that a S Sardinia block located NE of Balearic Islands rotated 30° CCW during the 30–21 Ma Liguro‐Provençal rifting, and was decoupled from N Sardinia along the left‐lateral Nuoro fault. After 21 Ma, Corsica‐Sardinia underwent a drift‐related 60° CCW rotation as a whole. A re‐analysis of available paleomagnetic results shows that Permian data from N Sardinia‐Corsica align with European directions considering a 60° CCW rotation, whereas Permian and mid Jurassic data from S Sardinia match European directions only after considering a ∼35° CCW Iberia rotation besides the 90° post‐Eocene event. We suggest that S Sardinia was part of Iberia, and rotated CCW during both Aptian Iberia drift and Oligo‐Miocene Liguro‐Provençal opening. Our data, along with recent paleomagnetic results from Calabria, suggest that S Sardinia, Balearic Islands, Calabria, Peloritan, Kabylies, and Alboran were fragments of “Greater Iberia,” joined to Iberia before 30 Ma Liguro‐Provençal rifting.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41433757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Substantial Upper Plate Faulting Above a Shallow Subduction Megathrust Earthquake: Mechanics and Implications of the Surface Faulting During the 2016 Kaikoura, New Zealand, Earthquake 浅层俯冲大逆冲地震上的大量上板块断裂:2016年新西兰凯库拉地震中地表断裂的力学和意义

IF 4.2 1区地球科学

Tectonics Pub Date : 2023-04-28 DOI: 10.1029/2022TC007645

M. Herman, K. Furlong, H. Benz

{"title":"Substantial Upper Plate Faulting Above a Shallow Subduction Megathrust Earthquake: Mechanics and Implications of the Surface Faulting During the 2016 Kaikoura, New Zealand, Earthquake","authors":"M. Herman, K. Furlong, H. Benz","doi":"10.1029/2022TC007645","DOIUrl":"https://doi.org/10.1029/2022TC007645","url":null,"abstract":"The 2016 moment magnitude 7.8 Kaikoura, New Zealand, earthquake occurred at the southern end of the Hikurangi subduction zone where the upper plate above the shallow megathrust is exposed sub‐aerially. As a result, the substantial co‐seismic deformation in the upper plate above the megathrust rupture was observed geologically and geodetically. We explore the relationship between this surface faulting and the subduction megathrust rupture and find that the greatest upper plate fault slip occurred coincident (in time and location) with the megathrust rupture. Models of Coulomb stress change demonstrate that these surface faults become positively loaded as the upper plate rebounds during the megathrust event, favoring fault slip. In addition, during the megathrust rupture these faults terminate against an uncoupled subduction plate interface. We simulate the effects of decoupling at the base of these faults and find that very large fault slip is an expected consequence of this decoupling, allowing near‐complete strain release. In contrast, typical strike‐slip faults, pinned at their base, would have lower amounts of fault slip. These two conditions—increased Coulomb stress and basal decoupling—combine to produce the extreme co‐seismic upper plate faulting observed above the shallow Kaikoura megathrust earthquake. Similar conditions occur in other global subduction zones, but in most subduction zones the region above the coupled megathrust is underwater and poorly observed. Our analysis of the Kaikoura earthquake indicates a need to reevaluate patterns of strain accumulation and release in these regions, rather than assuming simple models of elastic rebound.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45813793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Lake Level Changes and Holocene Extension Rate Across the NS‐Trending Peiku Co‐Gyirong Faults, Southern Tibet 藏南北纬向佩库-科-吉荣断裂全新世湖平面变化与扩展速率

IF 4.2 1区地球科学

Tectonics Pub Date : 2023-04-25 DOI: 10.1029/2022TC007644

Kang Li, Xi-wei Xu, P. Tapponnier, Wenjun Kang, Shiguang Wang

{"title":"Lake Level Changes and Holocene Extension Rate Across the NS‐Trending Peiku Co‐Gyirong Faults, Southern Tibet","authors":"Kang Li, Xi-wei Xu, P. Tapponnier, Wenjun Kang, Shiguang Wang","doi":"10.1029/2022TC007644","DOIUrl":"https://doi.org/10.1029/2022TC007644","url":null,"abstract":"Precise studies of Quaternary extension rates across NS‐trending normal faults in southern Tibet are important to understand the recent tectonic evolution of the high plateau. As one of the six main, southernmost Tibetan rifts, the ∼NS‐trending Peiku Co‐Gyirong rifts and intervening horst (PGR), co‐involve the west‐dipping Gyirong normal fault (GF) and the east‐dipping Peiku Co normal faults (PKF). Using unmanned aerial vehicle (UAV) high‐resolution topographic data, 14C dating of lake shorelines, and 10Be cosmogenic exposure dating of alluvial surfaces, we assess the offsets and constrain the ages of fans and lake level variations at four sites along these rift faults. Across the PKF's southern segment, our measurements at three sites are consistent with offsets of ∼4.7–6.5 m during the last ∼12.3 ka. Across the GF, a larger total offset of ∼8.5 m accrued since ∼10.4 ka. Using the average, exposed, 60° dip angle of the PKF implies a total Holocene EW extension rate of 0.72 ± 0.08 mm/yr across the PGR. Overall, our results are in keeping with published extension rates of ∼0.6–1.7 mm/yr across other southern Tibetan rifts, supporting the inference that the total, ≈EW, late Quaternary extension rate throughout southern Tibet is 9 ± 2 mm/yr. That there has been no surface faulting since at least ∼6.9 ka implies that the Gyirong County area, west of Peiku Co, may be at risk of Mw ≈ 6.9? event.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41931681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Origin of Seismic and Tectonic Activity Underlying the Sichuan Basin, Central China 四川盆地地震与构造活动的成因

IF 4.2 1区地球科学

Tectonics Pub Date : 2023-04-25 DOI: 10.1029/2022TC007629

Z. Su, R. Bürgmann, E. Wang

{"title":"The Origin of Seismic and Tectonic Activity Underlying the Sichuan Basin, Central China","authors":"Z. Su, R. Bürgmann, E. Wang","doi":"10.1029/2022TC007629","DOIUrl":"https://doi.org/10.1029/2022TC007629","url":null,"abstract":"The Sichuan basin, located adjacent to the eastern margin of the Tibetan Plateau, serves as an ideal marker for testing the extrusion process of the plateau. The basin is seismically active, with the strongest earthquake, the 2008 Mw 7.9 Wenchuan earthquake, occurring in the Longmen Shan range along its northwestern edge. A new regional compilation of focal mechanism solutions of earthquakes in and surrounding the basin reveals that a large fraction of the events have focal depths ranging between 8 and 25 km, corresponding to the crystalline basement of the basin. Seismic deformation involves right‐lateral oblique reverse faults, mostly trending northeast–southwest, similar to the kinematics of the mainshock of the Wenchuan earthquake. Shallow earthquakes (3–8 km) suggest that some of the seismic faults rupturing the crystalline basement are growing toward the surface. To the southwest, the seismicity transitions to activity along the left‐lateral Xianshuihe–Xiaojiang fault zone. The spatial relationship between these two sets of fault zones is consistent with a model in which the Sichuan basin responds to the southeast extrusion of the Chuan‐Dian block at the southeast margin of the plateau by a counterclockwise bookshelf rotation of the crystalline basement. This deformation pattern initiated ∼4–2 Ma, as shown by the age of the Xiaojiang fault segment. The history of left‐lateral movement along the Xianshuihe‐Xiaojiang fault can be traced back to ∼12 Ma when the eastward growth of the Tibetan Plateau resulted in the shortening of both the Longmen Shan thrust belt and the sedimentary over the Sichuan basin.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47380892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Breaking the Ring of Fire: How Ridge Collision, Slab Age, and Convergence Rate Narrowed and Terminated the Antarctic Continental Arc 打破火环:脊碰撞、板块年龄和辐合速率如何使南极大陆弧变窄并终止

IF 4.2 1区地球科学

Tectonics Pub Date : 2023-04-18 DOI: 10.1029/2022TC007634

A. Burton‐Johnson, J. Bastías, S. Kraus

{"title":"Breaking the Ring of Fire: How Ridge Collision, Slab Age, and Convergence Rate Narrowed and Terminated the Antarctic Continental Arc","authors":"A. Burton‐Johnson, J. Bastías, S. Kraus","doi":"10.1029/2022TC007634","DOIUrl":"https://doi.org/10.1029/2022TC007634","url":null,"abstract":"The geometry of the Antarctic‐Phoenix Plate system, with the Antarctic Plate forming both the overriding plate and the conjugate to the subducting oceanic plate, allows quantification of slab age and convergence rate back to the Paleocene and direct comparison with the associated magmatic arc. New Ar‐Ar data from Cape Melville (South Shetland Islands, SSI) and collated geochronology shows Antarctic arc magmatism ceased at ∼19 Ma. Since the Cretaceous, the arc front remained ∼100 km from the trench whilst its rear migrated trenchward at 6 km/Myr. South of the SSI, arc magmatism ceased ∼8–5 Myr prior to each ridge‐trench collision, whilst on the SSI (where no collision occurred) the end of arc magmatism predates the end of subduction by ∼16 Myr. Despite the narrowing and successive cessation of the arc, geochemical and dyke orientation data shows the arc remained in a consistently transitional state of compressional continental arc and extensional backarc tectonics. Numerically relating slab age, convergence rate, and slab dip to the Antarctic‐Phoenix Plate system, we conclude that the narrowing of the arc and the cessation of magmatism south of the SSI was primarily in response to the subduction of progressively younger oceanic crust, and secondarily to the decreasing convergence rate. Increased slab dip beneath the SSI migrated the final magmatism offshore. Comparable changes in the geometry and composition are observed on the Andean arc, suggesting slab age and convergence rate may affect magmatic arc geometry and composition in settings currently attributed to slab dip variation.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48702241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

New Paleomagnetic Constraints on the Amalgamation of the Tuva and Mongolia Blocks From Late Carboniferous Andesites in the Mongolia Block 蒙古地块晚石炭世安山岩对图瓦地块和蒙古地块合并的新古地磁约束

IF 4.2 1区地球科学

Tectonics Pub Date : 2023-04-01 DOI: 10.1029/2022TC007683

Qian Ren, Shihong Zhang, Mingcai Hou, A. Chen, Huaichun Wu, Tianshui Yang, Haiyan Li

{"title":"New Paleomagnetic Constraints on the Amalgamation of the Tuva and Mongolia Blocks From Late Carboniferous Andesites in the Mongolia Block","authors":"Qian Ren, Shihong Zhang, Mingcai Hou, A. Chen, Huaichun Wu, Tianshui Yang, Haiyan Li","doi":"10.1029/2022TC007683","DOIUrl":"https://doi.org/10.1029/2022TC007683","url":null,"abstract":"The Tuva‐Mongolia collage system comprises the Tuva Block (TVB) and the Mongolia Block (MOB), which are located in the eastern Central Asian Orogenic Belt (CAOB). The timing of amalgamation of the TVB and MOB is unclear. To address this, we conducted a combined geochronological and paleomagnetic study of the andesitic Member 1 of the Baoligaomiao Formation, in the southeastern MOB. The andesites have a U‐Pb zircon age of 314.2 ± 1.7 Ma. A total of 65 paleomagnetic samples from 10 sites were subjected to stepwise thermal demagnetization and had stable magnetic signals. After removal of the low‐temperature viscous components acquired in the recent geomagnetic field, stable high‐temperature components (HTCs) were isolated from most samples. The HTCs passed the fold, conglomerate, and reversal tests, demonstrating their primary origins. Moreover, these andesites have averaged out paleosecular variations. The paleomagnetic pole for the MOB is located at 30.5°N/14.6°E (A95 = 7.4°) at ca. 314 Ma. Combining our new results with published late Paleozoic paleomagnetic poles for the MOB and TVB suggests that the two blocks were distant from each other during the Middle Devonian and merged into a single TVB‐MOB by ca. 315 Ma. The Devonian‐Carboniferous paleomagnetic, paleobiogeographic, and geological data indicate that the multiple microcontinents in the CAOB were separated by numerous ocean basins during the Middle Devonian. At ca. 315 Ma, the TVB‐MOB, Kazakhstan, and Siberia were amalgamated to form a ribbon‐like continent, which was associated with the evolution of the Mongol‐Okhotsk Ocean.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":"16 10","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41294105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Issue Information 问题信息

IF 4.2 1区地球科学

Tectonics Pub Date : 2023-04-01 DOI: 10.1002/tect.21729

引用次数: 0

Jurassic Evolution of the Dunhuang Basin and Its Implications for the Early History of the Altyn Tagh Fault, Northeast Tibet Plateau 敦煌盆地侏罗纪演化及其对青藏高原东北部阿尔金断裂带早期历史的启示

1区地球科学

Tectonics Pub Date : 2023-04-01 DOI: 10.1029/2022tc007620

Dai Shuang, Ma Xiaojun, Zhao Zhenbin, Fan Xin, Wang Yilin, Wang Zixuan, Zhang Xiang, Cai Lipiao, Deng Wei, Hou Xubo, Xu Jianjun, Li Jiasheng

{"title":"Jurassic Evolution of the Dunhuang Basin and Its Implications for the Early History of the Altyn Tagh Fault, Northeast Tibet Plateau","authors":"Dai Shuang, Ma Xiaojun, Zhao Zhenbin, Fan Xin, Wang Yilin, Wang Zixuan, Zhang Xiang, Cai Lipiao, Deng Wei, Hou Xubo, Xu Jianjun, Li Jiasheng","doi":"10.1029/2022tc007620","DOIUrl":"https://doi.org/10.1029/2022tc007620","url":null,"abstract":"Abstract Basin evolution along the northeastern Tibetan Plateau related to the Altyn Tagh Fault (ATF) has significant implications for deciphering the formation of the Tibetan Plateau. However, the Mesozoic history of the ATF is still not well understood. In this contribution, we present a comprehensive sedimentologic and provenance analysis of the Jurassic Dunhuang Basin (DHB) to reconstruct the basin prototype and evolution and to discuss the early history of the ATF. The basin infill consists of late‐Early through Late Jurassic sediments interbedded with basalt, which were deposited in alluvial to lacustrine environments during the Early to Middle Jurassic, and in fluvial to fan delta environments during the Late Jurassic. The analyses of gravel component, paleocurrent and detrital zircon U‒Pb geochronology indicate that the clastic sediments were mainly derived from peripheral areas of the Bei Shan (north), Altyn Tagh—Qilian Shan (south), and the internal Sanwei Shan. Combined with seismic reflection data interpretations, our results suggest that rifting started by the activation of bilateral boundary faults during the Early Jurassic. This was followed by extension and associated magmatism due to subcrustal ductile necking and increased heat flux during the Middle Jurassic, and by final transformation into subsidence sag related to boundary fault die‐out or weakening during the Late Jurassic. We conclude that the DHB formed in an extensional setting generated by the far‐field effects of the Bangong‐Nujiang Ocean closure during the Jurassic, and that the ATF consisted of three subordinate normal faults rather than a sinistral strike‐slip fault during the Jurassic.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135170520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Ten Thousand Years of Paleo‐Earthquakes Record of the Magallanes‐Fagnano Plate Boundary Fault in Tierra del Fuego, Argentina 一万年的古地震——阿根廷火地岛麦哲伦-法格诺板块边界断层记录

IF 4.2 1区地球科学

Tectonics Pub Date : 2023-04-01 DOI: 10.1029/2022TC007305

Sandrine Roy, R. Vassallo, J. Martinod, C. Sue

{"title":"Ten Thousand Years of Paleo‐Earthquakes Record of the Magallanes‐Fagnano Plate Boundary Fault in Tierra del Fuego, Argentina","authors":"Sandrine Roy, R. Vassallo, J. Martinod, C. Sue","doi":"10.1029/2022TC007305","DOIUrl":"https://doi.org/10.1029/2022TC007305","url":null,"abstract":"The Magallanes‐Fagnano Fault is an active left‐lateral strike‐slip fault that cuts across Tierra del Fuego, forming the boundary between the South American and the Scotia plates. This fault may trigger strong earthquakes, as documented by the occurrence of two Mw ≥ 7.5 in December 1949. However, this region is characterized by one of the shortest historical archives in the world and by a growing population. The geological record is therefore needed in order to characterize the seismic information over a longer time scale and to improve the seismic hazard assessment. We conducted extensive field work, neotectonic mapping and excavated two paleoseismic trenches across one of the sharpest tectonic scarps in the Eastern onshore portion of the fault. Using scarp‐derived colluvial wedges, cross‐cutting relations, and 28 radiocarbon samples, we document evidences of at least six paleo‐earthquakes during the Holocene. Paleoseismic record is particularly accurate for the last two thousand years, for which period we determine an average recurrence interval of 1080 ± 150 years. For repeated earthquakes of same magnitude as the 1949 event, this recurrence interval is compatible both with the known geodetic and geomorphic slip rates. However, “paired earthquakes” in less than one or two centuries may also occur, suggesting that fault behavior could be characterized by irregular seismic cycles.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":" ","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41437058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0