CSEDI Collaborative Research: The Thermal, Petrological, and Seismological Structure of Subducting Oceanic Lithosphere

该项目的目标是将热模型和动力学模型与俯冲带的地震学数据相结合，以显示玄武岩和辉长岩向榴辉岩缓慢转化的地震学证据。PI首先产生一个运动学热模型，该模型产生瞬时和稳态热结构以及俯冲板块和上覆地幔楔体的压力-温度-时间演化。接下来，使用平衡相变模型和动力学相变模型来预测矿物组合、密度和地震波速。然后，通过其预测波形频散和转换相位幅度的观测地震特性的能力来评估计算的速度结构。然后，通过迭代重复来最小化岩石学预测的速度结构和地震学观测的速度结构之间的不匹配。如果假设中等深度地震需要高流体压力，那么脱水反应的轨迹和由此产生的挥发通量也可以用来预测震源位置，并与观测到的地震震中进行比较。由此产生的俯冲板块的热、岩石学和地震学性质的综合模型将进一步深入了解其他板块边界过程，如中深地震、弧岩浆作用和挥发分的循环。

9809832AbersThe goal of this project is integration of thermal and kinetic models with seismological data for subduction zones that exhibit seismological evidence for sluggish transformation of basalt and gabbro to eclogite. The PIs begin by producing a kinematic thermal model that yields transient and steady-state thermal structures and the pressure-temperature-time evolution of the subducting slab and overlying mantle wedge. Next, equilibrium and kinetic phase transformation models are used to predict mineral assemblages, densities, and seismic wave speeds. The calculated velocity structure is then evaluated by its ability to predict observed seismic properties of waveform dispersion and converted phase amplitudes. Misfit between the petrologically predicted and the seismologically observed velocity structure is then minimized by iterative repetition. If the assumption is made that high fluid pressures are required for intermediate depth earthquakes, then the loci of dehydration reactions and the resultant volatile flux can also be used to predict hypocenter locations and compared to observed earthquake hypocenters. The resulting integrated model of the thermal, petrological, and seismological properties of subducting slabs will yield further insight into other plate boundary processes such as intermediate-depth earthquakes, arc magmatism, and the recycling of volatiles.