Collaborative Research: Space-Based Measurements of Crustal Deformation along the Entire Dead Sea Fault System (Eastern Mediterranean)

合作研究：沿整个死海断层系统（东地中海）地壳变形的天基测量

• 批准号: 0948487
• 负责人: Francisco Gomez
• 金额: $ 29.03万
• 依托单位: University of Missouri-Columbia
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-15 至 2017-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0948487&HistoricalAwards=false
• 关键词: Collaborative; Research; Space; Based; Measurements

This study assembles the first, comprehensive view of near-field strain along the entire Dead Sea fault system using Global Positioning System (GPS) measurements. The fault system, a prominent element of the eastern Mediterranean geodynamic framework, bounds the Arabian and Sinai plates and links proto-oceanic spreading in the Red Sea (Gulf of Aqaba) with the Arabian-Eurasian collision (southern Turkey). Spanning more than 800 km, the left-lateral Dead Sea fault system ranks among the large continental transform systems of the world. With mean recurrence intervals between 500 to 1,100 years for large earthquakes on different sections and a paucity of large (magnitude greater than 7) earthquakes during the past two centuries, the fault system is an excellent locale to understand the relationship between earthquake recurrence and crustal deformation along a slow moving (less than 10 mm/yr) transform fault. By the fourth year of this project, most GPS sites (survey and new continuous) will have 1-sigma uncertainties less than 0.5 mm/yr. The resulting GPS velocity field will provide a basis for kinematic and geodynamic modeling of the Dead Sea fault system that will elucidate fundamental aspects of transform tectonics, as well as broader issues pertaining to eastern Mediterranean tectonics (e.g., internal deformation of the Sinai and Arabian plates, nature of the Dead Sea fault-East Anatolian Fault-Cyprus arc triple junction, age and geological evolution of the Dead Sea fault). Key issues addressed by the research include: 1) variation of slip rates along the transform and the implications about existing plate tectonic models for the region; 2) comparison between present-day slip rates with geological estimates with implications for the timing of initiation of the main parts of the Dead Sea fault system and its relationship to the Arabia-Eurasia collision and Red Sea rifting; 3) slip transfer and strain partitioning at fault bends and step-overs (e.g., the Lebanese restraining bend and the Dead Sea Basin); 4) the influence of lithospheric rheology on strain partitioning along a transform.The Dead Sea fault system ranks among the major continental transform fault systems in the world. In addition to elucidating geodynamic aspects of the eastern Mediterranean region, focused studies on the fault system can yield insight into tectonic and geodynamic processes operating along continental transforms, in general. From a structural perspective, the Dead Sea fault system is relatively simple when compared with other transform fault systems. The structural simplicity permits relatively straightforward modeling of the earthquake cycle and crustal deformation processes, which can yield fundamental insight pertinent to more complicated fault systems, such as the San Andreas fault system. To this end, sufficient historical and palaeoseismic records of large earthquakes exist to facilitate such studies along most of the Dead Sea fault system. This study provides the critical constraints on present-day crustal deformation using high-precision GPS measurements. Additionally, results from this project will be directly applicable for an urgently needed improvement in the understanding of the earthquake hazard in a region that is potentially overdue for a large earthquake. Regional earthquake hazard is a concern for nearby megacities including Damascus, Beirut, Amman, Aleppo, and Jerusalem.

这项研究组装的第一个，全面的看法近场应变沿着整个死海断层系统使用全球定位系统（GPS）测量。断层系统是东地中海地球动力学框架的一个重要组成部分，是阿拉伯和西奈板块的边界，并将红海（亚喀巴湾）的原始海洋扩张与阿拉伯-欧亚碰撞（土耳其南部）联系起来。死海左行断裂系统横跨800多公里，是世界上大型大陆转换系统之一。断层系统不同地段大地震的平均复发间隔在500 ~ 1100年之间，在过去的两个世纪里很少发生大地震（震级大于7），因此，它是了解沿着缓慢移动（小于10 mm/年）转换断层地震复发与地壳形变之间关系的一个极好场所。到本项目的第四年，大多数GPS站点（调查和新的连续站点）的1-sigma不确定度将小于0.5 mm/年。由此产生的GPS速度场将为死海断层系统的运动学和地球动力学建模提供基础，这将阐明转换构造的基本方面，以及与东地中海构造有关的更广泛的问题（例如，西奈和阿拉伯板块的内部变形、死海断层-东安纳托利亚断层-塞浦路斯弧三联点的性质、死海断层的年龄和地质演化）。研究的关键问题包括：1）滑动速率沿着转换的变化及其对该地区现有板块构造模型的影响; 2）现今滑动速率与地质估计之间的比较及其对死海断裂系统主要部分的启动时间及其与阿拉伯-欧亚碰撞和红海裂谷的关系的影响; 3）在断层弯曲和台阶处的滑动转移和应变分配（例如，黎巴嫩约束弯曲和死海盆地）; 4）岩石圈流变学对沿着转换应变分配的影响。死海断裂系是世界上主要的大陆转换断裂系之一。除了阐明东地中海地区的地球动力学方面，重点研究断层系统可以产生洞察构造和地球动力学过程操作沿着大陆转换，一般。从构造的角度来看，死海断层系统与其他转换断层系统相比相对简单。结构的简单性允许相对简单的地震周期和地壳变形过程的建模，这可以产生有关更复杂的断层系统，如圣安德烈亚斯断层系统的基本见解。为此，有足够的历史和古地震记录的大地震存在，以促进这样的研究沿沿着大部分死海断层系统。这项研究提供了使用高精度GPS测量的现今地壳形变的关键约束。此外，该项目的结果将直接适用于一个地区，这是一个潜在的大地震逾期的地震危险的理解迫切需要的改进。区域地震危险是大马士革、贝鲁特、安曼、阿勒颇和耶路撒冷等附近大城市的担忧。