UNcovering the role of Pyroclasts on volcanIc jet Noise – UNPIN

揭示火山碎屑对火山喷射噪音的作用 – UNPIN

• 批准号: 419092521
• 负责人: Dr. Ulrich Küppers, since 9/2022
• 金额: --
• 依托单位: Sektion Mineralogie, Petrologie und Geochemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/419092521?language=en
• 关键词: UNcovering; role; Pyroclasts; volcanIc; jet

During explosive volcanic eruptions, magma is fragmented and ejected as tephra. The energy required for driving an explosive eruption depends on a variable combination of intrinsic (e.g., outgassing of volatiles dissolved in magma) and extrinsic (e.g., evaporation of external water) processes. Tephra in the atmosphere can pose significant and varied hazards to society and infrastructures. The timing and the intensity of an eruption are not, or only insufficiently, foreseeable, and yet predictions ahead of time are essential to assess and mitigate volcanic hazards.Volcanic activity can be monitored directly on site as well as remotely, e.g. via space-based systems or earth-based seismic and acoustic networks. In particular, acoustic signals are increasingly used for monitoring active volcanoes in remote areas. Volcanoes emit acoustic signals in both the audible and the infrasonic spectral range. The goal of acoustic monitoring is to relate a measured acoustic signal with the specific eruption process. However, the interpretation of these signals is still difficult, because the underlying physics, developed for the flow of pure air, ignore the complex reality of volcanic environments. To date, there are no comprehensive datasets explaining the influence of volcano-relevant conditions on the acoustic signals.The aim of this project is to determine the influence of volcano-specific dynamic conditions on the measurable acoustic signals, in particular:- the presence of (volcanic) particles, and their volume fraction and size;- the volume, pressure, and temperature of the explosion-driving gas;- the geometry of the volcanic vent ("nozzle shape"); and- the morphology of the entire volcanic edifice.For this purpose, scaled, specially designed shock-tube experiments will be performed to simulate impulsive volcanic eruptions ("starting jets"). Acoustic recording of these laboratory experiments will uncover the influence of these parameters on the associated acoustic signals, thus providing unique insights into the dynamics of particle-laden jets and their acoustic properties. The scaled and reproducible laboratory experiments will then be compared with the analysis of volcanic eruptions. The results will open new doors to our capacity to interpret the acoustic signals generated during explosive volcanic eruptions, contributing significantly to an improved eruption characterization and ensuing risk assessment and the related resilience of people and society to active volcanoes.

在火山爆发期间，岩浆被分裂并以火山灰的形式喷出。驱动爆炸喷发所需的能量取决于内在的（例如，溶解在岩浆中的挥发物的脱气）和外在的（例如，外部水的蒸发）过程。大气中的火山灰可能对社会和基础设施造成重大和各种危害。火山爆发的时间和强度是不可预见的，或仅仅是不可预见的，但提前预测对评估和减轻火山灾害至关重要，可以直接在现场监测火山活动，也可以通过天基系统或地面地震和声学网络进行远程监测。特别是，声学信号越来越多地用于监测偏远地区的活火山。火山发出的声音信号在可听和次声频谱范围。声学监测的目标是将测量的声学信号与特定的喷发过程相关联。然而，对这些信号的解释仍然很困难，因为为纯净空气流动而开发的基础物理学忽略了火山环境的复杂现实。到目前为止，还没有全面的数据集来解释火山相关条件对声学信号的影响。本项目的目的是确定火山特有的动态条件对可测量的声学信号的影响，特别是：（火山）颗粒及其体积分数和大小;-爆炸驱动气体的体积、压力和温度;-火山口的几何形状（“喷嘴形状”）;以及-整个火山大厦的形态。为此，将进行按比例的、特别设计的激波管实验，以模拟脉冲式火山喷发（“启动射流”）。这些实验室实验的声学记录将揭示这些参数对相关声学信号的影响，从而提供对载有颗粒的射流及其声学特性的动力学的独特见解。然后，将把按比例和可重复的实验室实验与火山爆发的分析进行比较。研究结果将为我们解释火山爆发期间产生的声学信号的能力打开新的大门，大大有助于改进火山爆发的特征描述和随后的风险评估以及人民和社会对活火山的相关复原力。