Direct monitoring of active geohazards: emerging geophysical tools for deep-water assessments
Direct monitoring of active geohazards: emerging geophysical tools for deep-water assessments
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DOI：
10.3997/1873-0604.2017033
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发表时间：
2017-08-01
影响因子：
1.6
通讯作者：
Belal, Mohammad
中科院分区：
文献类型：
--
作者：
Clare, Michael A.;Vardy, Mark E.;Belal, Mohammad
海底电缆、管道和其他基础设施网络支撑着我们的日常生活，提供通信链路、信息和能源供应。尽管这些网络具有全球重要性，但它们很容易受到一些自然海底灾害的破坏，包括山体滑坡、浊流、流体流动和冲刷。传统的地球物理技术，如高分辨率反射地震和侧扫声纳，通常用于地质灾害评估。这些传统工具为路线规划和设计提供了必要的信息；然而，这种调查只能提供过去过程的间接证据，而不能观察或测量地质灾害本身。因此，许多基于数值的影响模型缺乏现场尺度校准，并且在深水地质灾害的触发因素、性质和频率方面存在许多不确定性。最近的技术进步现在可以通过直接监测来逐步改变他们的理解。我们概述了一些新兴的监测工具，以及它们如何量化深水地质灾害评估的关键参数。在动态区域的重复海底调查表明，仅仅依靠过去沉积物的证据可能导致对地质灾害事件的代表性不足。声学多普勒电流分析提供了对浊度流结构的新见解，而仪器移动传感器则首次记录了这些流底部的运动性质。现有的和定制的电缆网络可以实现高带宽、低功耗和分布参数的测量，例如海底大面积的应变。这些技术提供了有价值的新测量方法，将改善地质灾害评估，并应与传统的地球物理工具以互补的方式部署。
Seafloor networks of cables, pipelines, and other infrastructure underpin our daily lives, providing communication links, information, and energy supplies. Despite their global importance, these networks are vulnerable to damage by a number of natural seafloor hazards, including landslides, turbidity currents, fluid flow, and scour. Conventional geophysical techniques, such as high-resolution reflection seismic and side-scan sonar, are commonly employed in geohazard assessments. These conventional tools provide essential information for route planning and design; however, such surveys provide only indirect evidence of past processes and do not observe or measure the geohazard itself. As such, many numerical-based impact models lack field-scale calibration, and much uncertainty exists about the triggers, nature, and frequency of deep-water geohazards. Recent advances in technology now enable a step change in their understanding through direct monitoring. We outline some emerging monitoring tools and how they can quantify key parameters for deep-water geohazard assessment. Repeat seafloor surveys in dynamic areas show that solely relying on evidence from past deposits can lead to an under-representation of the geohazard events. Acoustic Doppler current profiling provides new insights into the structure of turbidity currents, whereas instrumented mobile sensors record the nature of movement at the base of those flows for the first time. Existing and bespoke cabled networks enable high bandwidth, low power, and distributed measurements of parameters such as strain across large areas of seafloor. These techniques provide valuable new measurements that will improve geohazard assessments and should be deployed in a complementary manner alongside conventional geophysical tools.