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

夏威夷-帝王海山链是地球上最著名的热点岩浆作用例子，火山在远离板块边界的地方形成，位于地幔下部的热点地区上方。关于创造夏威夷-帝王链火山和其他地方火山的基本地球过程，以及这些火山的巨大质量是如何由它们下面的岩石物质支撑的，仍然存在许多问题。这项研究将涉及两次海洋探险，以对热点产生的岩浆地壳进行地震成像，并获得关于地壳体积、其组成、它如何沿着岛链变化以及构造板块如何随着火山重量变形的关键信息。除了获得对夏威夷-帝王链形成的根本洞察外，这项研究还将有助于更全面地评估夏威夷岛国地区的地质灾害。地震数据将成像火山大楼内和周围洋壳中的断层，可用于评估地震、海啸和海底滑坡的危害。该项目涉及强有力的国家和国际合作。研究巡航将提供极好的机会让学生参与数据采集和分析，结果将成为大规模公共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-帝王海山链上岩浆添加的控制，提供对大洋岩石圈流变性的基本约束，解决热点膨胀的起源，并评估板块变形对挠曲的地震和海啸的影响。该计划是使用沿夏威夷-帝王海山链四个500公里长的横断面、间隔15公里的海底地震仪获取一致的2D、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、加载时岩石圈的年龄以及地形隆起的存在或不存在的巨大差异。横断面足够长，可以捕捉到岩石圈对火山加载到挠曲凸起的弯曲响应。利用广角地震资料建立的处理后的地震反射剖面和速度模型，将约束加到地壳的岩浆的体积和分布，以及火山建筑物内和加载的大洋板块内的断层。新的地震约束将与重力、磁力、水深和地球化学数据相结合，作为弯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智力优势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.