RAPID: The nature and physics of the Montecito debris flows of January 9, 2018, increasing community resiliency to debris flow hazards

泥石流造成了广泛的破坏和人员生命和基础设施的损失，仅在过去沿着太平洋沿岸和太平洋西北部就发生了几起重大悲剧。2018年1月9日，加州圣巴巴拉县Montecito村发生三起大型泥石流，造成21人死亡，390多座房屋和商业建筑被毁或受损，当地交通关闭数周。这些流动是由加州历史上最大的野火托马斯大火发生后几天的强烈降水造成的。研究表明，托马斯火灾造成的泥石流危害可能会在受火灾影响的更广泛地区持续2年或更长时间。泥石流对Montecito社区的影响加剧，因为公众和地方灾害管理官员对泥石流的物理性质和导致泥石流的条件缺乏明确的了解。通过图书馆市政厅会议和在当地报纸上发表文章与公众直接互动，应有助于教育居民了解区域地质环境、使用和理解特定术语（“泥石流”，而不是听起来更好听的“山洪”或“泥石流”），并灌输一个现实的认识，这些迅速移动的巨石满载泥浆的危险和自我，通过立即注意应急管理指示进行保护。它还应该完善这些指示，明确的强制性疏散警告，而不是非强制性的suggestions.Current的理解的物理学的自然泥石流和流面剖面主要是基于残余泥石流沉积物的解释。 然而，要了解任何一个泥石流的物理特性，都需要收集重要的流动数据，而这些数据往往会在数月至数年内从地质记录中删除。Morell，Dunne和Keller将通过收集对时间敏感的现场数据来限制与2018年1月9日Montecito事件相关的物理泥石流过程的关键方面，这些数据包括峰值流的高度和流向，侵蚀和沉积源材料的体积以及泥石流沉积物的沉积特征，了解源区，峰值速度，流变学和流出所需的关键数据，大型泥石流的膨胀和冲刷。通过绘制沿沿着三个受影响水系的泥石流沉积物的详细地图和横截面图，该项目将描绘事件存款的范围和性质、造成泥石流和广泛破坏的地表流动物理现象，为同一地区可能在不久的将来发生的事件做好准备。它将评估泥石流移动巨石的能力，并试图确定未来流动和预警系统的情景。 该项目利用裸露地表的LiDAR数据（由圣巴巴拉县提供）作为野外工作的底图，以及泥石流发生后几天的航拍照片（由Geomni公司提供）。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Debris flows have caused widespread destruction and loss of human life and infrastructure, with several major tragedies unfolding just in the past 10 years along the Pacific coast and Pacific northwest. On January 9, 2018, three large debris flows in the village of Montecito, Santa Barbara County, California, killed 21 people, destroyed or damaged over 390 homes and commercial buildings, and closed all local traffic for several weeks. The flows were caused by intense precipitation in the days following the Thomas Fire, the largest wildfire in California history. Research suggests the debris flow hazards posed by the Thomas fire may continue for 2 or more years in the wider area affected by the fire. The impact of the debris flows on the Montecito community was increased because both the public and local hazard management officials lacked a clear understanding of the physics of debris flows and the conditions that lead to them. Direct interactions with the public through library Town Hall meetings and articles in the local newspapers should help to educate residents as to the regional geologic setting, the use and understanding of specific terminology ("debris flow" instead of the more benign-sounding "flash flood" or "mudslide"), and to instill a realistic understanding of the danger of these rapidly moving boulder-laden slurries and the need for self-preservation through immediate attention to emergency management instructions. It should also refine those instructions to be unequivocal mandatory evacuation warnings rather than non-mandatory suggestions.Current understanding of the physics of natural debris flows and flow-surface profiles is largely based on interpretation of remnant debris flow deposits. However, understanding the physics of any single debris flow requires the collection of important flow data that are often erased from the geologic record within months to several years. Morell, Dunne and Keller will constrain critical aspects of physical debris flow processes associated with the Jan 9, 2018 Montecito event by collecting time-sensitive field data as to the height and flow direction of the peak flow, the volume of eroded and deposited source material, and the sedimentary character of debris flow deposits, key data needed to understand the source regions, peak velocity, rheology, and the runout, bulking, and scouring of large debris flows. By constructing detailed maps and cross-sections of the debris flow deposits along the three affected drainages, the project will delineate the extent and nature of the event deposit, the surface flow physics that caused the debris flow and the widespread destruction, in preparation for potential near-future events from this same area. It will assess the power of the debris flows to move boulders and attempt to determine scenarios for future flows and warning systems. The project leverages bare-earth LiDAR data (supplied by the county of Santa Barbara) for use as base maps for field work, and aerial photos flown several days after the debris flows (supplied by the company Geomni).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.