Studies of Unusual Earthquakes: Volcanos and Landslides

异常地震研究：火山和山体滑坡

• 批准号: 0944055
• 负责人: Goran Ekstrom
• 金额: $ 24.75万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0944055&HistoricalAwards=false
• 关键词: Studies; Unusual; Earthquakes; Volcanos; Landslides

The project involves the investigation of anomalous seismic sources with a specific focus on slow earthquakes associated with volcanos and landslides. It builds on results and discoveries that have come from the systematic application of a long-period event detection algorithm to real-time and archive seismic data recorded on the Global Seismographic Network. For each year since 1991, more than 100 earthquakes of magnitude 5 or greater that are not reported in other catalogs have been detected and located using this algorithm. Many of these earthquakes are slow, and a large number of them have been associated with volcanos and landslides. The first goal of the project is to discriminate volcano and landslide earthquakes from other earthquakes that have been identified only by the long-period detection algorithm. The second goal is to relate those earthquakes that occur in volcanic regions to eruptive activity and changes in the geometry and behavior of magmatic plumbing systems. In particular, the project will involve a detailed comparative study of unusual earthquakes associated with the two greatest caldera collapses of basaltic volcanos over the last century, Fernandina (Galapagos Islands) and Miyakejima (Japan). The third goal is to investigate anomalous earthquakes associated with large landslide events. A recently developed methodology for determining the trajectory of the sliding mass during a landslide directly from the radiated seismic waves will be refined and improved and applied to several known and inferred landslide events in order to estimate dynamic landslide parameters.The project will lead to an improved characterization and discrimination of earthquake sources, and will help clarify the phenomenology of volcano and landslide earthquakes. The volcano investigations will provide new constraints on stress and deformation patterns within active volcanoes, as well as on the mechanics of caldera collapse and its relationship to magmatic transport and plumbing. The landslide investigations will lead to better characterization of the seismic radiation from landslide sources, and will provide new constraints on key landslide parameters, such as mass, runout, and effective coefficient of friction. The seismological analysis methods developed for these studies will contribute to improved monitoring capabilities for volcanos and landslides, which represent important classes of geohazards.

该项目涉及调查异常地震源，特别侧重于与火山和滑坡有关的慢震。它是在对全球地震台网记录的实时和存档地震数据系统应用长周期事件探测算法所取得的成果和发现的基础上建立的。自1991年以来，每年都有超过100次在其他目录中没有报告的5级或更大的地震被检测到并使用该算法定位。这些地震中有许多是缓慢的，其中许多与火山和山体滑坡有关。该项目的第一个目标是将火山和滑坡地震与仅由长周期检测算法识别的其他地震区分开来。第二个目标是将发生在火山地区的地震与喷发活动以及岩浆管道系统的几何形状和行为变化联系起来。特别是，该项目将涉及对与上个世纪两个最大的玄武岩火山口坍塌有关的不寻常地震进行详细的比较研究，这两个火山口是费尔南迪纳（加拉帕戈斯群岛）和三宅岛（日本）。第三个目标是调查与大型滑坡事件有关的异常地震。最近开发的一种直接从辐射地震波确定滑坡过程中滑坡体轨迹的方法将得到改进和提高，并应用于若干已知和推断的滑坡事件，以估计动态滑坡参数，该项目将改进对地震源的定性和鉴别，并将有助于澄清火山和滑坡地震的现象。火山调查将对活火山内部的应力和变形模式以及破火山口坍塌的力学及其与岩浆迁移和管道的关系提供新的限制。滑坡调查将导致更好地表征滑坡源的地震辐射，并将提供新的约束关键滑坡参数，如质量，跳动，和有效的摩擦系数。为这些研究开发的地震学分析方法将有助于提高对火山和山崩的监测能力，因为火山和山崩是重要的地质灾害类别。