CAREER: Deciphering Cavitation in Fluid-Filled Cracks and its Induced Seismicity through Integrated Physical Modeling

岩浆经常沿着裂缝（称为“岩脉”或“岩脉”）穿过火山下面的地面，了解它们的物理特性对于理解火山是如何工作的很重要。有人认为，岩脊或岩脉的快速生长导致岩浆中的气泡突然坍塌，导致周围岩石破裂和火山震动。如果这被证实，监测这些震动将使科学家能够实时跟踪堤坝的生长，这将有助于他们预测火山喷发的时间和规模。在这个CAREER项目中，Roohollah Askari博士将进行实验室实验，使气泡在充满液体的裂缝中生长和破裂，他将使用高速摄影和其他技术监测震动和裂缝生长的结果。他还将使用数学技术来证明他的实验室实验的发现适用于火山下的岩壁和岩脉，这些岩壁和岩脉当然要大得多，而且是由不同的材料构成的。阿斯卡里博士和他的团队（包括老师）也将根据实验制作一些教育视频，他将邀请来自波多黎各的大学生到他的实验室，这样他们就可以和他自己的学生一起学习实验技术。裂缝（岩壁和岩脉）对岩浆的输送起着重要的作用，通常是优先的流动路径。因此，了解岩浆裂缝生长的动力学及其诱发的地震活动性对于估计岩浆运移、监测新裂缝的发展和预测即将到来的火山喷发至关重要。空化引起的气泡-岩浆相互作用对裂纹动力学和扩展有显著影响。尽管对岩浆中的空化和气泡成核进行了广泛的研究，但由于裂缝流体与壁面之间复杂的相互作用，对充满流体的裂缝中的这些现象知之甚少。强到足以破坏裂缝壁、产生次级裂缝并被地震探测到的冲击波是岩浆裂缝空化的另一种可能结果。了解这一过程对于预测何时从先前存在的堤防或堤防发展成次级堤防或堤防至关重要。在这个CAREER项目中，Askari将开发两个模拟装置并进行一系列实验，以破译1)影响充液裂缝空化的基本因素，2)随后的子裂缝扩展机制，以及3)诱发地震活动。该项目将通过为波多黎各大学的学生提供暑期研究实习机会，促进来自代表性不足群体的学生的参与。将与教师和教育专家合作，开发、评估和更新以大学预科和大学水平学生为特色的实验教学视频。该奖项反映了美国国家科学基金会的法定使命，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。

Magma often moves through the ground beneath volcanoes along cracks (called 'dikes' or 'sills'), and understanding their physics is important for understanding how volcanoes work. It has been suggested that rapid growth of sills or dikes causes gas bubbles in magmas to collapse suddenly, causing cracking of the surrounding rock and volcanic tremors. If this is proven, monitoring these tremors will allow scientists to track dikes in real time as they grow, which will help them forecast the timing and size of eruptions. In this CAREER project, Dr. Roohollah Askari will conduct laboratory experiments to make bubbles in fluid-filled cracks grow and collapse, and he will monitor shaking and crack growth that result, using high-speed photography and other techniques. He will also use mathematical techniques to show that the discoveries from his laboratory experiments apply to sills and dikes under volcanoes, which are of course much larger and made of different materials. Dr. Askari and his team (including teachers) will also produce several educational videos based on the experiments, and he will host college students from Puerto Rico in his laboratory so they can learn experimental techniques along with his own students.Cracks (sills and dikes) contribute significantly to magma transport, often serving as preferential flow paths. Thus, understanding the dynamics of magmatic crack growth and its induced seismicity is crucial for estimating magma transport, monitoring the development of new cracks, and forecasting upcoming eruptions. Crack dynamics and growth may be affected significantly by bubble-magma interaction caused by cavitation. Although cavitation and bubble nucleation in magma have been studied generally, comparatively little is known about these phenomena in fluid-filled cracks, given the complex interaction between the crack fluid and walls. Shock waves that are strong enough to damage the crack walls, create sub-cracks, and be detected seismically are another possible outcome of cavitation in magmatic cracks. Understanding this process is critical to predicting when sub-dikes or sills can develop from a preexisting dike or sill. In this CAREER project, Askari will develop two analog apparatuses and conduct suites of experiments to decipher 1) the fundamental factors influencing cavitation in fluid-filled cracks, 2) the subsequent sub-crack growth mechanism, and 3) induced seismicity. This project will promote the engagement of students from underrepresented groups by offering summer research internships for students from the University of Puerto Rico. Instructional videos featuring the experiments and targeting pre-college and college-level students will be developed, assessed, and updated, in collaboration with teachers and education specialists.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.