Developing a Global Listening Network for Turbidity Currents and Seafloor Processes

开发浑浊流和海底过程的全球监听网络

• 批准号: NE/S009965/1
• 负责人: Mike Clare
• 金额: $ 1.57万
• 依托单位: NATIONAL OCEANOGRAPHY CENTRE
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FS009965%2F1
• 关键词: Developing; Global; Listening; Network; Turbidity

This ambitious project can make a major step-change in understanding of seafloor processes and geohazards by developing a listening network based on low-cost hydrophones (via acoustic noise in water column) and geophones (via ground shaking). This type of low-cost network has unusually widespread applications, but here we aim to answer fundamental questions about how submarine mass-flows (turbidity currents and landslides) are triggered, and then behave. These hazardous and often powerful (2-20 m/s) submarine events form the largest sediment accumulations, deepest canyons, and longest channel systems on our planet. Turbidity currents can runout for hundreds to thousands of kilometres, to break seabed cable networks that carry >95% of global data traffic, including the internet and financial markets, or strategic oil and gas pipelines. These flows play a globally important role in organic carbon and nutrient transfer to the deep ocean, and geochemical cycles; whilst their deposits host valuable oil and gas reserves worldwide. Submarine mass flows are notoriously difficult to measure in action, and there are very few measurements compared to their subaerial cousins. This means there are fundamental gaps in basic understanding about how submarine mass flows are triggered, their frequency and runout, and how they behave. Recent monitoring has made advances using power-hungry (active source) sensors, such as acoustic Doppler current profilers (ADCPs). But active-source sensors have major disadvantages, and cannot be deployed globally. They can only measure for short periods, are located on moorings anchored inside these powerful flows (which often carry the expensive mooring and sensors away), and they need multiple periods of expensive research vessels to be both deployed and recovered. We will therefore design, build and test passive sensors that can be deployed over widespread areas at far lower cost. These novel sensors will record mass-flow timing and triggers; and changes in front speed (from transit times), and flow power (via strength of acoustic or vibration signal).We will first determine how submarine mass flows are best recorded by hydrophones and geophones, and how that record varies with flow speed and type, or distance to sensor. Our preliminary work at three sites already shows that hydrophone and geophones do record mass-flows. Here we will determine the best way to capture that mass-flow signal, and to distinguish it from other processes. This will form the basis for then designing and field testing a new generation of low-cost smart sensors, which return data without expensive surface vessels; via pop-up floats and satellite links. Advances in technology make this project timely, as they allow on-board data processing by smart hydrophones to reduce data volumes, which can be triggered to record for short periods at much higher frequency. We will test the new smart sensors, and use them to answer two major science questions. First, do submarine flows in different settings show consistent modes of behaviour? Second, what triggers submarine flows in river-fed systems, and how are they linked to major river floods, earthquakes, and tropical cyclones? To do this, we will place these new sensors along the Congo Canyon (dilute river, passive margin, no cyclones) off West Africa, and the Gaoping Canyon (hyperpycnal river, active margin, frequent cyclones) offshore Taiwan.These sensors have other widespread applications. Low cost warning sensors would be a major advance for offshore hazard assessment, and leaks from CCS facilities or gas pipelines. Sensors that record landslides would be a step change for tsunami warning systems, or threats to valuable seabed infrastructure. This proposal is also particularly timely, because of advances in technology now allow on-board data processing and communication between smart sensors, which can be triggered to record for short periods at much higher frequency.

这个雄心勃勃的项目可以通过开发一个基于低成本水听器（通过水柱中的声学噪声）和地震检波器（通过地面震动）的监听网络，在了解海底过程和地质灾害方面取得重大进展。这种类型的低成本网络具有异常广泛的应用，但在这里，我们的目标是回答有关海底质量流（浊流和山体滑坡）如何触发的基本问题，然后表现。这些危险且通常强大（2-20米/秒）的海底事件形成了我们星球上最大的沉积物堆积，最深的峡谷和最长的通道系统。浊流可以绵延数百至数千公里，破坏承载超过95%全球数据流量的海底电缆网络，包括互联网和金融市场或战略石油和天然气管道。这些流动在有机碳和营养物向深海转移以及地球化学循环方面发挥着全球重要作用;同时其沉积物在全球范围内拥有宝贵的石油和天然气储量。众所周知，海底物质流很难在实际中测量，与它们的陆上兄弟相比，测量很少。这意味着对海底质量流如何触发、其频率和跳动以及其行为方式的基本理解存在根本性差距。最近的监测已经取得了进展，使用功耗（有源）传感器，如声学多普勒电流剖面仪（ADCP）。但是有源传感器有很大的缺点，不能在全球范围内部署。它们只能进行短期测量，位于锚定在这些强大水流中的系泊装置上（这些水流通常会将昂贵的系泊装置和传感器带走），并且它们需要多个周期的昂贵研究船来部署和回收。因此，我们将设计、建造和测试能够以低得多的成本部署在广泛地区的无源传感器。这些新的传感器将记录质量流的时间和触发;和前端速度的变化（通过渡越时间），和流功率（通过声学或振动信号的强度）。我们将首先确定如何最好地记录水下质量流水听器和地震检波器，以及如何记录随流速和类型，或传感器的距离变化。我们在三个地点的初步工作已经表明，水听器和地震检波器确实记录了质量流。在这里，我们将确定捕获质量流量信号的最佳方法，并将其与其他过程区分开来。这将成为设计和现场测试新一代低成本智能传感器的基础，这些传感器无需昂贵的水面船只即可通过弹出式浮标和卫星链路返回数据。技术的进步使这个项目及时，因为它们允许智能水听器进行机载数据处理，以减少数据量，这些数据量可以被触发，以更高的频率进行短时间记录。我们将测试新的智能传感器，并用它们来回答两个主要的科学问题。第一，不同环境下的海底水流是否表现出一致的行为模式？其次，是什么触发了河流系统中的海底流动，它们与主要河流洪水、地震和热带气旋有何联系？为此，我们将把这些新的传感器沿着西非的刚果峡谷（稀释河，被动边缘，没有气旋）和台湾近海的高平峡谷（高密度河，活动边缘，频繁的气旋）放置。这些传感器还有其他广泛的应用。低成本的预警传感器将是海上危险评估的一个重大进步，也是CCS设施或天然气管道泄漏的一个重大进步。记录山体滑坡的传感器将是海啸预警系统的一个步骤，或者是对宝贵的海底基础设施的威胁。这一提议也特别及时，因为技术的进步现在允许在智能传感器之间进行机载数据处理和通信，这些传感器可以被触发以更高的频率进行短时间记录。

项目成果

Predicting turbidity current activity offshore from meltwater-fed river deltas

• DOI: 10.1016/j.epsl.2022.117977
• 发表时间: 2023-02
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: L. Bailey;M. Clare;E. Pope;I. Haigh;M. Cartigny;P. Talling;D. Lintern;S. Hage;M. Heijnen

Quantifying the three-dimensional stratigraphic expression of cyclic steps by integrating seafloor and deep-water outcrop observations

通过整合海底和深水露头观测来量化循环步骤的三维地层表达

• DOI: 10.1111/sed.12772
• 发表时间: 2020
• 期刊: Sedimentology
• 影响因子: 3.5
• 作者: Englert R

Lessons learned from the monitoring of turbidity currents and guidance for future platform designs

• DOI: 10.1144/sp500-2019-173
• 发表时间: 2020-01-01
• 期刊: SUBAQUEOUS MASS MOVEMENTS AND THEIR CONSEQUENCES: ADVANCES IN PROCESS UNDERSTANDING, MONITORING AND HAZARD ASSESSMENTS
• 作者: Clare, Michael;Lintern, D. Gwyn;Apprioual, Ronan
• 通讯作者: Apprioual, Ronan

Efficient preservation of young terrestrial organic carbon in sandy turbidity-current deposits

• DOI: 10.1130/g47320.1
• 发表时间: 2020-09-01
• 期刊: GEOLOGY
• 影响因子: 5.8
• 作者: Hage, S.;Galy, V. V.;Talling, P. J.
• 通讯作者: Talling, P. J.

Preconditioning by sediment accumulation can produce powerful turbidity currents without major external triggers

• DOI: 10.1016/j.epsl.2021.116845
• 发表时间: 2021-03-03
• 期刊: EARTH AND PLANETARY SCIENCE LETTERS
• 影响因子: 5.3
• 作者: Bailey, Lewis P.;Clare, Michael A.;Lundsten, Eve
• 通讯作者: Lundsten, Eve