Shock wave hazards during explosive volcanic eruptions: an experimental investigation

火山喷发期间的冲击波危害：实验研究

• 批准号: 213034968
• 负责人: Dr. Teresa Scolamacchia
• 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: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/213034968?language=en
• 关键词: Shock; wave; hazards; during; explosive

Shock waves in explosive volcanic eruptions are poorly investigated. Several issues concerning their generation and propagation are still objects of great debate, and the associated hazards are currently downplayed in active volcanic area risk assessment. Evidence for such phenomena was recently recovered from one of the villages destroyed by the 1982 eruption of El Chichón volcano (Mexico). Micrometric craters produced by the impact of volcanic ash particles were found on the surface of a steel pole. The velocities of the impacts, was calculated by analytical methods as up to 980 m/s, similar to those reported theoretically and numerically for shock waves accompainying volcanic eruptions. The main goal of this proposal is to gain better insight into the mechanisms by which volcanic particles of different size/mass can be accelerated by shock waves, either given efficient momentum coupling with a gas phase or due to changes in the shock structure at the contact with particles. We plan to reproduce experimentally the impact craters on metal targets. Questions to be answered are: 1) What is the main process responsible for particle acceleration in the presence of shock waves? 2) What is the relationship between the grain-size, the mass load, the shape of the particles, and the high velocities calculated? 3) Is the steel’s temperature at the moment of impact an important factor in determining the magnitude of “cratering”? The results expected from this investigation, will 1) elucidate the processes associated with shock wave propagation during explosive eruptions, and 2) help to raise awareness about the hazards related to these phenomena while improving specific response strategies.

爆炸性火山喷发中的冲击波研究很少。关于它们的产生和传播的几个问题仍然是巨大争论的对象，相关的危险目前在活跃的火山区风险评估中被淡化。最近从1982年(墨西哥)El Chichón火山喷发摧毁的一个村庄中发现了这种现象的证据。在一根钢杆表面发现了火山灰颗粒撞击产生的微米陨石坑。用解析方法计算出的撞击速度高达980m/S，与理论和数值上报道的伴随火山喷发的冲击波的速度相似。这一提议的主要目标是更好地了解不同大小/质量的火山颗粒可被激波加速的机制，激波可以提供与气相有效耦合的动量，或者是由于与颗粒接触时激波结构的变化。我们计划在实验中重现撞击金属目标的陨石坑。要回答的问题是：1)在冲击波存在的情况下，粒子加速的主要过程是什么？2)颗粒大小、质量载荷、粒子形状和计算的高速之间的关系是什么？3)钢材在撞击瞬间的温度是决定“弹坑”大小的重要因素吗？这项调查的预期结果将1)阐明爆炸期间与冲击波传播相关的过程，2)有助于提高人们对与这些现象相关的危险的认识，同时改进具体的应对策略。