How do subduction zones initiate, develop and end: Imaging the Reversal of Subduction in the Solomon Islands

俯冲带如何开始、发展和结束：想象所罗门群岛的俯冲反转

• 批准号: NE/M00788X/1
• 负责人: Nicholas Harmon
• 金额: $ 6.66万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FM00788X%2F1
• 关键词: How; do; subduction; zones; initiate

Plate tectonics is a fundamental theory for explaining earthquakes, volcanoes, crustal deformation and therefore the motion at the Earth's surface. However very little is known about how destructive plate boundaries initiate, evolve and end. This is central to plate tectonics, as it is thought that the dominant driving force of plate motions is the gravitational pull of subducting plates.In the Solomon Islands and Papua New Guinea, the Pacific and Australian plates are converging. In the north one subduction zone is nearing the end of its life cycle as anomalously buoyant oceanic plate is stalling subduction. To the south in the San Cristobal Trench, a new subduction zone has initiated in response to continued convergence of the Pacific and Australian plates, making this the perfect place to understand subduction initiation and cessation. In this urgency proposal we will deploy seismometers for 1 year to record aftershocks from sequence of 4 major earthquakes with magnitudes between 7.1-7.6. These recordings and other recordings of earthquakes from around the globe will allow us to delineate with high accuracy the plate interfaces of the new and old subducting slabs and image the slab structures at depth. The structure of the old and new subduction zones will illuminate the processes occurring at depth which are shifting the force balance in the region to reverse the sense of subduction.The proposed experiment will be enhanced by concurrent studies scheduled to be deployed in Fall of 2014, which includes a multimillion pound ocean bottom seismic deployment by colleagues in Japan. The combined array will allow us to image the Pacific plate which is stalling the subduction, allowing us to investigate what conditions are necessary for a plate to halt the descent of the slab into the mantle. Thus we will be able to understand how subduction stops and starts.

板块构造理论是解释地震、火山、地壳变形以及地球表面运动的基本理论。然而，人们对破坏性板块边界是如何开始、演化和结束的知之甚少。这是板块构造的核心，因为人们认为板块运动的主要驱动力是俯冲板块的引力。在所罗门群岛和巴布亚新几内亚，太平洋和澳大利亚板块正在会聚。在北部，一个俯冲带正接近其生命周期的终点，因为浮力巨大的海洋板块正在停止俯冲。在南部的圣克里斯托瓦尔海沟，一个新的俯冲带已经启动，以应对太平洋和澳大利亚板块的持续会聚，使这里成为了解俯冲开始和停止的理想场所。在这项紧急提案中，我们将部署地震仪，为期一年，以记录4次震级在7.1-7.6之间的大地震的余震。这些记录和其他来自地球仪的地震记录将使我们能够高精度地描绘新老俯冲板块的板块界面，并对深部的板块结构进行成像。新旧俯冲带的结构将阐明发生在深处的过程，这些过程正在改变该地区的力平衡，以扭转俯冲的感觉。拟议的实验将通过计划于2014年秋季部署的并行研究得到加强，其中包括日本同事部署的数百万磅海底地震。组合的阵列将使我们能够对太平洋板块进行成像，使我们能够调查板块停止下沉到地幔的必要条件。因此，我们将能够理解俯冲是如何停止和开始的。

项目成果

Seismic imaging of a mid-lithospheric discontinuity beneath Ontong Java Plateau

• DOI: 10.1016/j.epsl.2016.06.026
• 发表时间: 2016-09
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: S. Tharimena;C. Rychert;N. Harmon

Upper mantle temperature and the onset of extension and break-up in Afar, Africa

• DOI: 10.1016/j.epsl.2015.02.039
• 发表时间: 2015-05-15
• 期刊: EARTH AND PLANETARY SCIENCE LETTERS
• 影响因子: 5.3
• 作者: Armitage, John J.;Ferguson, David J.;Harmon, Nicholas
• 通讯作者: Harmon, Nicholas

Source regions and reflection of infragravity waves offshore of the U . S .s P acific N orthwest

美国近海次重力波的源区和反射。

• DOI: 10.1002/2015jc010891
• 发表时间: 2015
• 期刊: Oceans
• 作者: Neale J

Joint inversion of teleseismic and ambient noise Rayleigh waves for phase velocity maps, an application to Iceland

• DOI: 10.1002/2016jb012934
• 发表时间: 2016-08
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: N. Harmon;C. Rychert

Synthetic waveform modelling of SS precursors from anisotropic upper-mantle discontinuities

来自各向异性上地幔不连续面的SS前体的综合波形建模

• DOI: 10.1093/gji/ggt474
• 发表时间: 2014
• 期刊: Geophysical Journal International
• 影响因子: 2.8
• 作者: Rychert C