Testing Models of Magma Movement along the East Pacific Rise Using Combined Geoditic and Numerical Experiments

摘要(0426575)-Cormier这是一个五年计划，将在四年内部署20个压力传感器阵列，以监测位于东太平洋隆起(9‘-10’N)的美国国家科学基金会资助的RIDGE 2000综合研究地点的岩浆注入情况。压力传感器可以成功地检测到大洋中脊上的小(厘米)到大(M)垂直运动。它们也相对便宜，可以在不提供服务的情况下长时间记录数据。为支持实地方案，将开展两项建模工作。第一个将解释测量的海底垂直位移，其中将包括来自现场的压力传感器数据。将开发耦合堤防入侵和基床排空的数值模型，其中包括考虑研究地点海底流变结构的算法。第二组模型将研究使用重复微水深测量来限制板块边界某一部分的表面变形模式的可行性。科学目标包括区分沿着快速扩张的大洋中脊的两种相互竞争的岩浆输送模式，第一种模式是熔体沿脊轴几乎垂直供应，第二种模式是熔体在山脊段中心提供并向山脊段末端传播。在第一种情况下，压力传感器网络将沿着被堤坝切割的管段部分预期均匀的垂直偏转，在第二种情况下，压力传感器将检测到管段中心附近的显著下沉。这项研究的动机来自于这样一个事实，即地震和火山集中在活动的构造板块边界上，然而，近80%的这些边界发生在海底，因此无法直接观察到那里发生的过程。该项目由伍兹霍尔海洋研究所的研究人员实施，将探测、描述、监测沿板块边界的岩浆注入事件，并对其进行模拟，该边界以快速和重复的岩浆注入事件和海底扩散为标志。这项工作的更广泛影响包括开发一种新的岩浆注入海底监测系统和附带的建模工具，这些工具有可能应用于其他板块边界、学生教育和培训，以及通过与RIDGE2000外联方案合作，以有意义的方式向公众和K-12提供关于该项目的信息。水深测量工具的发展也支持了海洋大地测量这一新兴领域。

Abstract (0426575) - CormierThis is a five-year program that will deploy of an array of 20 pressure sensors for four years to monitor magma injection at the NSF-funded RIDGE2000 integrated study site at the East Pacific Rise (9'-10'N). Pressure sensors can successfully detect small (cm) to large (m) vertical motions on mid-ocean ridges. They are also relatively inexpensive and can record data for long periods of time without service. In support of the field program, two modeling efforts will be carried out. The first will interpret measured vertical seafloor displacements that will incorporate the pressure sensor data from the field site. Numerical models of coupled dike intrusion and sill emptying will be developed that include algorithms that take into account the rheological structure of the seafloor at the study site. The second set of models will examine the feasibility of using repeat microbathymetric surveys to constrain surface deformation patterns across a section of a plate boundary. Scientific objectives include discrimination between the two competing models of magma delivery along fast-spreading mid-ocean ridges, the first being where melt is supplied nearly vertically along the ridge axis and the second being where melt is provided at ridge segment centers and propagates toward the segment ends. In the first case, uniform vertical deflections of the pressure sensor network would be expected along the part of a segment cut by a dike, and in the second, pressure sensors would detect significant subsidence near the segment center. Motivation for this study comes from the fact that earthquakes and volcanoes are concentrated on active tectonic plate boundaries, however, nearly 80% of these boundaries occur under the sea and therefore processes occurring there cannot be directly observed. This project, being carried out by researchers at the Woods Hole Institution of Oceanography, will detect, characterize, monitor, and model magma injection episodes along a plate boundary marked by rapid and repeated magma injection events and spreading of the seafloor. Broader impacts of this work include development of a novel magma injection seafloor monitoring system and accompanying modeling tools which have the potential for application to other plate boundaries, student education and training, and making information on the project available to the public and K-12 in a meaningful way through collaboration with the RIDGE2000 outreach program. Development of the bathymetric survey tools also supports the emerging field of marine geodesy.