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

俯冲描述了一个构造板块由于会聚而下降到毗邻构造板块下方的地幔的过程。目前在世界许多地区都可以发现活跃的俯冲带，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、新的洋壳的形成以及地球、海洋和大气之间的水交换方面发挥了基本作用。俯冲带也是全球火山和地震灾害的主要来源，2011年日本东北地区毁灭性的地震和海啸就是其中之一。因此，俯冲带是了解地球运行方式的主要关键之一，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，俯冲周期中很少受到关注的一个方面是终止阶段，在这个阶段，由于潜在的各种原因，下沉板块的下降停止。鉴于所有俯冲带的寿命都是有限的，这一过程很可能对我们大陆的演化方式产生了深远的影响，但到目前为止，还没有开发出可信的模型来说明在这种情况下地壳和上地幔可能会发生什么。这一知识差距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(马来西亚东部)的地质观测，改变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。北婆罗洲(马来西亚东部)上一次经历活跃俯冲是在500-600万年前。最近可能与俯冲终止有关的构造和过程的证据使其成为研究近地表地质和下伏地幔之间联系的理想环境。为了实现这一点，我将提供第一张俯冲后活动大陆边缘的详细图片，并将适当地解决之前在北婆罗洲下方发现的上地幔高速异常。结合对震源机制的分析，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。为了加强该项目的科学成果，并促进英国出口技术的改进，我们与仅有的几家全球地震传感器制造商之一Guralp Systems Limited(GSL)合作，Guralp Systems Limited(GSL)是唯一一家总部位于英国的公司。该提议的中心目标是在北婆罗洲陆上和近海部署密集的地震仪阵列，以记录当地和区域地震、近海气枪射击和周围地震噪声(大气扰动和海洋微震造成的地球“嗡嗡声”)，以便以高分辨率成像下伏地壳和地幔。离岸OBS的部署和主动拍摄将由我们的合作者中国科学院和国家海洋局中国进行。与此同时，我们将能够测试现有的新一代GSL仪器，改进它们的设计和性能，帮助开发新技术，并潜在地开拓新市场，从而加强GSL作为世界领先的地震仪器制造商公司的国际声誉和知名度。

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.