The Development of a Next Generation Subseabed Pore Pressure Insrument for Marine Hydrogeology: The PUPPI-II

PI建议开发一种新的海底孔隙压力仪器，类似于Peter Schultheiss在80年代开发的弹出式孔隙压力仪器（PUPPI）。仪器包由一个连接到喷枪和压载物上的上层控制单元组成。它是通过从船上自由落体来部署的，并将喷枪嵌入沉积物中。喷枪上的一个或多个端口连接到高分辨率压力传感器，并且初始插入压力脉冲、衰减和最终平衡与底部压力一起被沿着记录。平衡值和流体静力梯度之间的差异给出了过压或欠压的状态，并最终给出了应力状态和流体流动的性质。该仪器可以留在底部数月或数年，以连续记录压力，也可以在达到平衡后恢复。声学释放机构将命令单元与喷枪和压载物分离，并且命令单元漂浮到表面以进行回收。孔隙压力是一个基本的物理参数，用于确定沉积物内的应力现状以及流体和能量的输送速率。尽管如此，海洋水文地质界对孔隙压力的直接测量一直很少见。这主要是由于缺乏具有足够分辨率和其他重要品质的仪器。各种技术的最新进展使这种测量成为可能，国际海洋地球科学界对这种测量的兴趣重新高涨。更广泛的影响海底压力计的开发将需要国际合作以及与工业界的合作。正如项目执行人所指出的，这一文书可以成为一些国家和国际方案（资源、地理信息系统、海洋环境综合方案、海王星方案）的一个组成部分，并可用于解决代表这些方案所述目标的许多问题。此外，孔隙压力数据对于研究与社会相关问题的研究人员来说是有价值的，例如地震反应，天然气水合物形成和质量浪费事件。该提案包括对仪器设计研究生的支持。

The PIs propose to develop a new subseafloor pore pressure instrument similar to the Pop Up Pore Pressure Instrument (PUPPI) developed by Peter Schultheiss in the eighties. The instrument package consists of an upper command unit attached to a lance and ballast. It is deployed by free-fall from a ship and embeds the lance in the sediment. One or more ports on the lance are connected to a high resolution pressure transducer and the initial insertion pressure pulse, decay, and final equilibrium are recorded along with the bottom pressure. The difference between the equilibrium value and the hydrostatic gradient give the state of over- or underpressure and ultimately the state of stress and nature of fluid flow. The instrument can be left on the bottom for months or years for a continuous record of pressure or can be recovered after reaching equilibrium. An acoustic release mechanism separates the command unit from the lance and ballast and the command unit floats to the surface for recovery. Pore pressure is a fundamental physical parameter for determining the current state of stress and the rate of transport of fluid and energy within the sediment. In spite of this, direct measurements of pore pressure by the marine hydrogeology community have been rare. This has primarily been due to the lack of instrumentation with adequate resolution and other important qualities. Recent advances in various technologies have made such measurements possible and there has been a resurgence of interest for such measurements within the international marine geoscience community. Broader ImpactsDevelopment of the seafloor piezometer will require international collaboration as well as collaboration with industry. As the PIs point out, this instrument could become an integral part of a number of national and international programs (RIDGE, MARGINS, IODP, NEPTUNE), and could be used to address many of the questions that represent the stated goals of these programs. In addition, pore pressure data is valuable for researchers studying problems with societal relevance, such as earthquake responses, gas hydrate formation, and mass wasting events. The proposal includes support for a graduate student in instrument design.