Collaborative Research: Understanding the Spatio-Temporal Characteristics of Earthquakes at Axial Seamount Late in an Eruptive Cycle

合作研究：了解喷发周期后期轴状海山地震的时空特征

• 批准号: 1536219
• 负责人: William Wilcock
• 金额: $ 30.6万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1536219&HistoricalAwards=false
• 关键词: Collaborative; Research; Understanding; Spatio; Temporal

Axial Seamount is a hotspot volcano and the most magmatically active feature on the Juan de Fuca oceanic spreading center. The Ocean Observatories Initiative (OOI) cabled observatory at Axial provides a ground-breaking opportunity to capture volcano behavior leading up to, during, and following a seafloor eruption. Axial volcano erupted in 1998 and 2011 and, prior to April 2015, seafloor sensors showed that it was inflating with magma again. Over their first six months of operation, the cabled seismometers at Axial Seamount recorded increasingly high rates of small earthquake activity, supporting the inference that the volcano was in the late stage of its volcanic cycle. This was confirmed in late April 2015 when the volcano erupted. The researchers on this grant will work with both graduate and undergraduate students to analyze this first-ever seafloor volcanic event to be observed in real-time with seafloor sensors.This study will use the OOI cabled ocean bottom seismometer network to determine the pattern of earthquake activity at Axial Seamount to understand how stress at the spreading axis is partitioned spatially and temporally. The implications in terms of possible broad structures of hydrothermal flow will be assessed. Changes in the physical properties of the volcano through a volcanic cycle will be documented, with ultimate aim of advancing knowledge about how individual geologic events sum to produce long-term, steady oceanic spreading. Production of near-real time earthquake catalogs for the continuing OOI cabled seismic data stream will allow rapid identification of significant new events. Relocation analysis will yield relative earthquake locations accurate to within tens of meters, bringing structural features in the seismicity into focus. Focal mechanisms, repeating earthquakes, and shear wave splitting parameters will be obtained to further constrain the volcano's dynamics.

Axial Seamount是Hotspot火山，也是Juan de Fuca Oceanic扩展中心上最活跃的特征。轴向的海洋天文台倡议（OOI）有线天文台为捕获火山行为提供了开创性的机会，直到海底喷发，并在海底喷发中。轴向火山于1998年和2011年爆发，2015年4月之前，海底传感器表明它再次与岩浆充气。在他们的前六个月运行中，轴向海山的有线地震仪记录了越来越高的小地震活动速率，这支持了火山处于火山循环的后期的推断。这在2015年4月下旬爆发时得到了证实。这项赠款的研究人员将与研究生和本科生一起分析这次海底火山赛事，将在海底传感器中实时观察到。这项研究将使用OOI有电导的海洋底部底座底座网络网络来确定在轴向隔离的地震活动模式，以确定轴向接触的地震模式，以了解如何在散布轴上进行分配的散布式斑点和时间上的斑点和时间上的斑点。将评估对水热流的可能广泛结构的含义。将记录通过火山循环的火山物理特性的变化，并最终的目的是促进有关单个地质事件如何产生长期，稳定的海洋扩散的知识。为继续OOI电缆的地震数据流的生产近时间地震目录将允许快速识别重大的新事件。搬迁分析将使相对地震位置准确地置于数十米以内，从而使地震性的结构特征成为重点。将获得焦点机理，重复地震和剪切波分裂参数，以进一步限制火山的动态。