Collaborative Research: Seismic imaging of volcano construction, underplating and flexure along the Hawaiian-Emperor Seamount Chain

夏威夷-皇帝海山链是地球上最著名的热点岩浆作用的例子，火山在远离板块边界的地幔热区域上方形成。许多问题仍然存在，关于创造夏威夷-皇帝链和其他地方的火山的基本地球过程，以及这些火山的巨大质量如何由它们下面的岩石材料支撑。 这项研究将包括两次海上考察，对热点产生的岩浆地壳进行地震成像，并获得有关地壳体积、成分、沿着岛链如何变化以及构造板块如何因火山重量而变形的关键信息。除了对夏威夷-皇帝链的形成有基本的了解外，这项研究还将有助于对夏威夷岛屿地区的地质灾害进行更全面的评估。 地震数据将显示火山构造内和周围海洋地壳内的断层，可用于评估地震、海啸和海底滑坡的危险。该项目涉及强有力的国家和国际合作。研究航行将为学生参与数据采集和分析提供极好的机会，其结果将成为大规模公众宣传和教育工作的基础。该项目计划的数据采集和分析的科学目标是检查夏威夷-皇帝海山链沿着岩浆增加的控制，提供海洋岩石圈流变特性的基本限制，探讨热点膨胀的起源，并评估板块因挠曲而变形对地震和海啸的影响。该计划是利用海底地震仪，沿夏威夷-皇帝海山链的四条500公里长的断面，以沿着15公里的间距，获取重合的二维、深穿透地震反射数据以及广角反射/折射数据。 这些断面的位置将包括岩浆侵位和体积流量的时间，岩石圈在加载时的年龄和地形隆起的存在/不存在的广泛变化。断面足够长，以捕获岩石圈的弯曲响应，火山加载到弯曲隆起。经处理的地震反射剖面图和根据广角地震数据建立的速度模型将限制岩浆加到地壳中的数量和分布，以及火山建造物内和承载的海洋板块内的断层。新的地震约束条件将与重力、磁力、测深和地球化学数据相结合，并用作挠曲分析和数值模拟的基础，以获得对地壳和岩石圈动力学的基本新见解。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。

The Hawaii-Emperor Seamount Chain is the most well-known example on Earth of hotspot magmatism, where volcanoes form far from plate boundaries above hot regions in the underlying mantle. Many questions remain about the fundamental earth processes that create the volcanoes of the Hawaii-Emperor chain and elsewhere, and how the enormous mass of these volcanos is supported by the rock material below them. This study will involve two seagoing expeditions to seismically image the magmatic crust created by the hotspot and obtain critical information about the crust's volume, its composition, how it varies along the island chain, and how the tectonic plate deforms in response to the weight of the volcanoes. In addition to gaining fundamental insight into the formation of the Hawaiian-Emperor chain, the study will also be beneficial to a more comprehensive assessment of geohazards for the Hawaiian island region. Seismic data will image faults within the volcanic edifice and in the surrounding oceanic crust that can be used to evaluate seismic, tsunami and submarine landslide hazards. The project involves strong national and international collaborations. The research cruises will provide excellent opportunities to involve students in data acquisition and analysis, and the results will be the basis for a large public outreach and education effort.The scientific objectives of the planned data acquisition and analysis of this project are to examine controls on magmatic addition along the Hawaiian-Emperor seamount chain, provide fundamental constraints on rheological properties of oceanic lithosphere, address the origin of the hotspot swell, and assess implications for earthquakes and tsunamis from plate deformation in response to flexure. The plan is to acquire coincident 2D, deep-penetration seismic reflection data as well as wide-angle reflection/refraction data using ocean bottom seismometers spaced at 15 km along four 500-km-long transects across the Hawaiian-Emperor seamount chain. The locations of these transects will encompass wide variations in the timing of magma emplacement and volume flux, the age of the lithosphere at the time of loading and the presence/absence of a topographic swell. The transects are sufficiently long to capture the flexural response of the lithosphere to volcano loading out to the flexural bulge. The processed seismic reflection profiles and velocity models created from wide-angle seismic data will constrain the volume and distribution of magmatic addition to the crust as well as faulting within the volcanic edifice and within the loaded oceanic plate. New seismic constraints will be combined with gravity, magnetic, bathymetric and geochemical data and used as the basis for flexural analysis and numerical modeling to gain fundamental new insights into crust and lithosphere dynamics.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.