Advanced seismic instruments for challenging environments: road testing UK technology to unravel earthquake hazard and tectonics in North Borneo

适用于挑战性环境的先进地震仪器：道路测试英国技术以揭示北婆罗洲的地震危险和构造

• 批准号: NE/R013500/1
• 负责人: Simone Pilia
• 金额: $ 44.72万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FR013500%2F1
• 关键词: Advanced; seismic; instruments; challenging; environments

Subduction describes the process in which one tectonic plate descends into the mantle beneath an adjoining tectonic plate as a result of convergence. Currently active subduction zones can be found in many parts of the world, including western South America, the NW Pacific and southeast Asia. Subduction may have been operating on Earth for over three billion years, and plays a fundamental role in the creation and evolution of the continents, the generation of new oceanic crust and the exchange of water between the Earth, oceans and atmosphere. Subduction zones are also the principal source of volcanic and seismic hazard around the globe, with the devastating 2011 Tohoku earthquake and tsunami in Japan being one of many examples of the destructive power they hold.Subduction zones, therefore, are one of the primary keys to understanding how our Earth works, and as a result, they have been the subject of intensive study by Earth Scientists from around the world. However, one aspect of the subduction cycle that has received little attention is the termination phase, where, for potentially a variety of reasons, the descent of the downgoing slab ceases. Given that all subduction zones have a finite lifetime, this process is likely to have profoundly influenced the way in which our continents have evolved, but to date no credible model has been developed for what might happen to the crust and upper mantle in such circumstances. This knowledge gap means that there is a unique and timely opportunity to provide new insight into this fundamental Earth process.I aim to make a step-change in our understanding of how post-subduction continental margins evolve and how the crust and upper mantle interact by combining seismic imaging, earthquake source mechanism studies and geological observations in North Borneo (east Malaysia), which last experienced active subduction 5-6 million years ago. Evidence of recent structures and processes which may be connected to subduction termination make it an ideal setting to examine links between the near surface geology and underlying mantle. To achieve this, I will provide the first detailed picture of an active post-subduction continental margin, and will properly resolve a previously identified upper mantle high velocity anomaly beneath North Borneo. Together with analysis of earthquake source mechanisms, my new imaging results will help build a model of how the continental lithosphere responds to subduction termination. To enhance the scientific outcomes of the project, and contribute to the improvement of UK export technology, we have teamed up with one of only a few global manufacturers of seismic sensors, Guralp Systems Limited (GSL), which is the only one based in the UK. The central objective of the proposal is to deploy a dense array of seismometers both onshore and offshore North Borneo to record local and regional earthquakes, active shooting of airgun shots off-shore and ambient seismic noise (the Earths "hum" caused by atmospheric disturbances and oceanic microseisms), in order to image the underlying crust and mantle at high resolution. The off-shore OBS deployment and active shooting will be carried out by our collaborators the Chinese Academy of Sciences and State Ocean Administration of China. At the same time, we will be able to test existing new generation GSL instruments, improve their design and performance, help in the development of new technologies and potentially open new markets, thus strengthening GSL's international reputation and visibility as a world-leading firm of seismic instrument manufacturers.

俯冲作用描述了一个构造板块由于会聚而下降到相邻构造板块之下的地幔中的过程。目前活跃的俯冲带可以在世界许多地方找到，包括南美洲西部，西北太平洋和东南亚。俯冲作用可能已经在地球上运行了30多亿年，在大陆的形成和演化、新海洋地壳的生成以及地球、海洋和大气之间的水交换方面发挥着根本性的作用。俯冲带也是地球仪周围火山和地震灾害的主要来源，2011年日本东北地区的毁灭性地震和海啸就是其破坏力的众多例子之一。因此，俯冲带是了解地球如何运作的主要关键之一，因此，它们一直是世界各地地球科学家深入研究的主题。然而，俯冲周期的一个方面很少受到关注，那就是终止阶段，在那里，由于各种潜在的原因，下降板片停止下降。鉴于所有俯冲带都有一个有限的寿命，这一过程很可能深刻地影响了我们大陆的演变方式，但迄今为止，还没有建立可靠的模型来说明在这种情况下地壳和上地幔可能发生什么。这种知识空白意味着有一个独特而及时的机会来提供对这一基本地球过程的新见解。我的目标是通过结合地震成像、震源机制研究和北婆罗洲的地质观测，使我们对俯冲后大陆边缘如何演化以及地壳和上地幔如何相互作用的理解发生飞跃（东马来西亚），最后一次经历了活跃的俯冲500 - 600万年前。可能与俯冲终止有关的近期构造和过程的证据使其成为研究近地表地质与下伏地幔之间联系的理想环境。为了实现这一目标，我将提供一个活跃的俯冲后大陆边缘的第一个详细的图片，并将妥善解决以前确定的上地幔高速异常下北婆罗洲。结合震源机制的分析，我的新成像结果将有助于建立大陆岩石圈如何响应俯冲终止的模型。为了提高该项目的科学成果，并为改善英国出口技术做出贡献，我们与全球为数不多的地震传感器制造商之一Guralp Systems Limited（GSL）合作，这是唯一一家总部位于英国的制造商。该提案的中心目标是在北婆罗洲的陆上和海上部署密集的地震仪阵列，以记录当地和区域地震、海上气枪的主动射击和周围的地震噪音（大气扰动和海洋微震引起的地球“嗡嗡声”），以便以高分辨率对下面的地壳和地幔成像。海上OBS部署和主动拍摄将由我们的合作者中国科学院和中国国家海洋局进行。与此同时，我们将能够测试现有的新一代GSL仪器，改进其设计和性能，帮助开发新技术并潜在地打开新市场，从而加强GSL作为世界领先的地震仪器制造商的国际声誉和知名度。

项目成果

Collision-Induced Subduction Polarity Reversal Explains the Crustal Structure of Northern Borneo: New Results From Virtual Deep Seismic Sounding (VDSS)

碰撞引起的俯冲极性反转解释了北婆罗洲的地壳结构：虚拟深震探测 (VDSS) 的新结果

• DOI: 10.17863/cam.89335
• 发表时间: 2022
• 作者: Linang H