Collaborative research: Crustal magma plumbing of the Santorini volcanic system

圣托里尼火山是一座与地中海俯冲带有关的活弧型火山，它适应了非洲和欧洲之间的构造汇聚。圣托里尼最近经历了地质动荡，这项研究将记录目前地下岩浆的分布情况。由于火山系统是半淹没的，圣托里尼是使用海洋仪器进行详细成像的理想地点。仅靠陆上研究无法实现足够宽的孔径或足够密集的覆盖范围，从而能够绘制整个地壳的岩浆地图。通过确定地壳的物理性质，这个来自美国、英国和希腊的国际团队试图了解不同深度的岩浆是如何结晶的，以及这可能意味着一个基本研究问题--最终构成大陆的地壳是如何形成的，以及一个地质灾害问题--目前的岩浆分布是否表明，可能在大喷发之前发生持续的火山膨胀？一名美国学生将获得地震数据采集经验和最先进的处理方法培训，同时还将学习在国际研究团队中工作。圣托里尼火山地壳的地震成像旨在限制海底岩浆的分布和表观结晶程度随深度的任何变化。这一遗址被视为世界范围内硅弧火山的代表，因此其结果可能具有其他弧火山的代表性。海底地震仪和陆地地震仪将被部署进行为期几周的野外实验。这些仪器以及拖曳的多通道拖缆将记录有源源信号。以圣托里尼为中心的10 x 50英里的东北方向的轨道线将以史无前例的分辨率成像下层地壳结构。数据分析强调互补的地震方法：(1)高密度三维各向同性和各向异性走时层析成像(2)全波形反演层析成像和波形模拟，以获得更高分辨率和更准确的弹性性质及其空间变异性。

Santorini is an active arc volcano associated with the Mediterranean subduction zone, which accomodates tectonic convergence between Africa and Europe. Santorini recently experienced geologic unrest and this study will document the current distribution of subsurface magma. Because the volcanic system is semi submerged Santorini is an ideal site for detailed imaging using marine instrumentation. Onshore-only studies cannot achieve broad enough aperture or dense enough coverag to allow mapping of magma throughout the crust. By determining the physical properties of the crust, this international team from the U.S., U.K., and Greece, seek to understand how magma at different depths crystallizes and what that might imply about both a basic research question- how does crust that eventually makes up continents form, and a geohazard question- does the current distribution of magma indicate a likelihood of sustained volcano inflation that might precede a major eruption? A US student will gain seismic data acquisition experience and training in state-of-the-art processing methods, while also learning to work within an international research team. Seismic imaging of the crust at Santorini volcano is designed to constrain the distribution of subseafloor magma and any variation in extent of apparent degree of crystallization with depth. This site is viewed as representative of silicic arc volcanoes worldwide, so results could be representative of other arc volcanoes. Ocean bottom seismometers, and land seismometers will be deployed for a few-week field experiment. Active source signals will be recorded by these instruments as well as by a towed, multi-channel streamer. Tracklines laid out along a north-east trending, 10 x 50 mile swath, with Santorini at the center, will be image the lower crustal structure with unprecedented resolution. Data analysis emphasizes complementary seismic approaches: (1) Dense 3D isotropic and anisotropic travel time tomography (2) Full waveform inversion tomography and waveform modeling to obtain higher resolution and more accurate elastic properties and their spatial variability.