Collaborative Proposal: Evolution of Lava Channel Networks: Implications for Lava Flow Hazards and Mitigation

熔岩河流是夏威夷等地火山活动的标志性表现。熔岩流虽然很少致命，但通常会对财产构成风险，这种风险可能足以让政府当局决定修建屏障来转移这些流动(例如，在Mt.1983年、1991年和2001年在意大利埃特纳，1960年在夏威夷)。然而，建造屏障与其说是一门科学不如说是一门艺术，熔岩流与地形屏障之间的相互作用还没有得到很好的研究。在熔岩流动的地貌中也可能存在障碍，或者以先前存在的地形的形式存在，或者以熔岩流侵位和固化时建造的地形的形式存在。遇到障碍物的熔岩流要么围绕它们分裂，形成独立的(较小和较慢的)熔岩流叶，要么可能被较大的障碍物(如悬崖)聚集成大型(和快速移动的)流。必须了解这些行为，以模拟活跃流动的推进，这对于评估和减轻熔岩流动频繁地区(如夏威夷、意大利和冰岛)的火山灾害至关重要。这项研究将使用(1)分析近期夏威夷熔岩流中保存的渠道网络，(2)进行实验室实验，以确定当粘性流体(包括模拟流体和熔融玄武岩)遇到地形障碍时，障碍对粘性流体下坡运动的影响，以及(3)从实验中发展并应用于活动熔岩流的模型，来研究复杂熔岩流的发展和稳定性。此外，近期夏威夷熔岩流中的河道网络将在高分辨率数字高程模型(DEM)和航空照片上进行识别，分析网络模式，并进行实地调查。实地研究将包括通过摄影测量记录熔岩-地形相互作用结构，以及建造特定河道特征的三维模型。将使用Tandem-X卫星雷达成像和摄影测量为目标区域创建新的数字高程模型。这种多管齐下的方法将通过俄勒冈大学、布里斯托尔大学、拉蒙特-多尔蒂地球天文台和美国地质调查局夏威夷火山天文台的科学家之间的合作而成为可能。

Rivers of molten lava are iconic manifestations of volcanic activity in places like Hawaii. Although rarely fatal, lava flows commonly pose risks to property, risks that may be sufficient that government authorities decide to build barriers to divert those flows (for example, at Mt. Etna, Italy, in 1983, 1991 and 2001, and in Hawaii in 1960). However, barrier construction is more an art than a science, and the interaction between lava flows and topographic barriers has not been well researched. Barriers may also exist in the landscape over which lava travels, either in the form of pre-existing topography or in topography that is constructed as lava flows are emplaced and solidify. Lava flows that encounter barriers will either split around them to form separate (smaller and slower) lava flow lobes, or may be focused by large obstacles (such as cliffs) into large (and fast-moving) flows. These behaviors must be understood to model the advance of active flows, which is essential for assessing and mitigating volcanic hazards in regions of frequent lava flow activity (such as Hawaii, Italy and Iceland). This research will investigate the development and stability of complex lava flows using (1) analysis of channel networks preserved in recent Hawaiian lava flows, (2) laboratory experiments performed to determine the effect of obstacles on the downslope movement of viscous fluids (both analogue fluids and molten basalt) when they encounter topographic obstacles, and (3) models developed from the experiments and applied to active lava flows. Additionally, channel networks in recent Hawaiian lava flows will be identified on high resolution digital elevation models (DEMs) and aerial photos, analyzed for network patterns, and investigated in the field. Field studies will include documentation of lava-topography interaction structures via photogrammetry and construction of 3D models of specific channel features. New digital elevation models will be created for target areas using both TanDEM-X satellite-based radar imaging and by photogrammetry. This multi-pronged approach will be made possible by collaborations among scientists at the University of Oregon, University of Bristol, Lamont-Doherty Earth Observatory, and the USGS Hawaiian Volcano Observatory.