Collaborative Research: The North Anatolian Fault system in the Marmara Sea, Turkey - Insights from the Plio-Quaternary evolution of a multi-stranded transform

合作研究：土耳其马尔马拉海的北安纳托利亚断层系统 - 多股变换的普里奥-第四纪演化的见解

• 批准号: 1537719
• 负责人: Christopher Sorlien
• 金额: $ 8.71万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2018-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1537719&HistoricalAwards=false
• 关键词: Collaborative; Research; North; Anatolian; Fault

Part 1The North Anatolian Fault, a young continental transform fault, splits into several branches and forms a transtensional basin. Most of the strain is associated with the Northern Branch, which created three 1200-m deep basins. It has been proposed that the strain is focusing on the Northern Branch and that the Central and Southern branches are being abandoned. However, recent seafloor data demonstrate continued activity of the Central Branch. The will PI use new data collected in 2013 and 2014 in combination with a large suite of available previous data, to map the stratigraphy and faulting related to the Central Branch of the NAF and extend stratigraphic age model covering the past 0.5 Ma to greater depth and age. These data will be used to investigate two fundamental questions about transform fault systems: 1) what is the interplay between branches as a transform fault system evolves? And 2) how do cumulative slip and pre-existing structures affect the evolution of faults and strain partitioning? The Northern Branch is relatively continuous and single stranded while the Southern Branch is discontinuous and multi-stranded. By contrasting the slip history of these branches, the PIs will resolve whether different accumulated slip can fully account for these different fault properties or whether they are permanently influenced by pre-existing structure. The project will further cement international collaboration with Turkey via shared research and personnel exchanges, including Turkish graduate students. It will also support a female US postdoc and two undergraduate summer interns. Information relevant to seismogenic activity beneath the Marmara Sea is highly societally relevant considering that this seismic gap is home to 25% of Turkey's population and much of its industry. Part 2A continental transform is expected to originate as a distributed network of small faults with complex geometries that, with continued slip, gradually coalesce and simplify into a through-going fault. The North Anatolian Fault (NAF), a young continental transform, has been proposed as a prime example of this process. In the Marmara Sea, however, the NAF splits into several branches and forms a transtensional basin. Most of the strain is associated with the Northern Branch, which spawned three 1200-m deep basins. It has been proposed that the strain is focusing on the Northern Branch and that the Central and Southern branches are being abandoned. However, recent seismic and bathymetry data demonstrate continued activity of the Central Branch. These new data collected in 2013 and 2014 image the stratigraphy and numerous individual fault strands on the southern shelf of the Marmara Sea. The PI will use these data, in combination with a large suite of available previous data, to map the stratigraphy and faulting related to the Central Branch of the NAF. The PIs propose to extend our published stratigraphic age model covering the past 0.5 Ma to greater depth and age. Earliest Pliocene fill of Messinian (~5 Ma) erosional valleys dated on land will be projected short distances to our near-shore reflection data to provide a base to the age model. Based on this stratigraphic framework, they will evaluate fault kinematics of many strands over the southern Marmara Sea during the last several million years. Basin modeling will be used to separate the effects of sediment loading, compaction and tectonic subsidence and test the extension estimates. These data will be used to investigate two fundamental questions about transform fault systems: 1) What is the interplay between branches as a transform fault system evolves? And 2) how do cumulative slip and pre-existing structures affect the evolution of faults and strain partitioning? The Northern Branch is relatively continuous and single stranded while the Southern Branch is discontinuous and multi-stranded. By contrasting the slip history of these branches, the PIs will resolve whether different accumulated slip can fully account for these different fault properties or whether they are permanently influenced by pre-existing structure. The project will further cement international collaboration with Turkey via shared research and personnel exchanges, including Turkish graduate students. It will also support a female US postdoc and two undergraduate summer interns. Information relevant to seismogenic activity beneath the Marmara Sea is highly societally relevant considering that this seismic gap is home to 25% of Turkey's population and much of its industry. The results will also be highly relevant to the southern San Andreas Fault and other similarly multi-stranded transform fault systems.

第一部分北安纳托利亚断裂是一条年轻的大陆转换断裂，它分裂成几个分支，形成一个张扭盆地。大部分应变与北方分支有关，该分支形成了三个1200米深的盆地。有人提出，该菌株集中在北方分支，而中央和南方分支正在被放弃。然而，最近的海底数据表明，中央分支仍在继续活动。PI将使用2013年和2014年收集的新数据，结合大量现有的先前数据，绘制与NAF中央分支相关的地层和断层图，并将覆盖过去0.5 Ma的地层年龄模型扩展到更大的深度和年龄。这些数据将被用来调查两个基本问题的转换故障系统：1）是什么样的分支之间的相互作用，作为一个转换故障系统的演变？累积滑动和先存构造如何影响断层演化和应变分配？北方分支是相对连续的和单链的，而南方分支是不连续的和多链的。通过对比这些分支的滑动历史，PI将解决不同的累积滑动是否可以完全解释这些不同的断层性质，或者它们是否受到预先存在的结构的永久影响。该项目将通过共享研究和人员交流，包括土耳其研究生，进一步巩固与土耳其的国际合作。它还将支持一名女性美国博士后和两名本科生暑期实习生。与马尔马拉海下的孕震活动相关的信息具有高度的社会相关性，因为这一地震空白区是土耳其25%人口和大部分工业的家园。第二部分大陆转换预计起源于一个复杂几何形状的小断层的分布式网络，随着持续的滑动，逐渐合并并简化为一个贯通的断层。北安纳托利亚断层（NAF），一个年轻的大陆转换，已被提出作为这一过程的一个主要例子。然而，在马尔马拉海，NAF分裂成几个分支，形成一个张扭盆地。大部分应变与北方分支有关，它产生了三个1200米深的盆地。有人提出，该菌株集中在北方分支，而中央和南方分支正在被放弃。然而，最近的地震和测深数据表明，中央分支仍在继续活动。2013年和2014年收集的这些新数据对马尔马拉海南部大陆架的地层和许多单独的断层链进行了成像。PI将使用这些数据，结合大量现有的先前数据，绘制与NAF中央分支相关的地层和断层图。PI建议将我们公布的地层年龄模型（涵盖过去0.5 Ma）扩展到更大的深度和年龄。最早上新世填充的墨西拿（~5马）侵蚀山谷在陆地上的日期将投影短距离我们的近岸反射数据，提供一个基础的年龄模型。根据这一地层框架，他们将评估过去几百万年来马尔马拉海南部多条断层的运动学。盆地模型将用于分离沉积物负荷、压实和构造沉降的影响，并测试延伸估计。这些数据将被用来调查两个基本问题的转换故障系统：1）是什么样的分支之间的相互作用，作为一个转换故障系统的演变？累积滑动和先存构造如何影响断层演化和应变分配？北方分支是相对连续的和单链的，而南方分支是不连续的和多链的。通过对比这些分支的滑动历史，PI将解决不同的累积滑动是否可以完全解释这些不同的断层性质，或者它们是否受到预先存在的结构的永久影响。该项目将通过共享研究和人员交流，包括土耳其研究生，进一步巩固与土耳其的国际合作。它还将支持一名女性美国博士后和两名本科生暑期实习生。与马尔马拉海下的孕震活动相关的信息具有高度的社会相关性，因为这一地震空白区是土耳其25%人口和大部分工业的家园。 这些结果也将与南部圣安德烈亚斯断层和其他类似的多股转换断层系统高度相关。