基于环境噪声相关性的全波形反演,研究展示黄石岩浆系统横波速度的新层析图像,表明黄石公园硅质岩浆库相关的横波速度下降了30%以上。最慢的地震波速度(横波速度小于2.3千米/秒)出现在3至8千米的深度之间,与估计喷发纹岩体的组合深度相重叠。假设黄石的岩浆系统是一个具广泛分布熔融体的晶质物,那么预估部分熔融的部分为16 - 20%。
据悉,地震层析成像提供了对黄石公园地壳岩浆系统的关键见解,包括试图了解地下的熔体分布和当前火山生命周期的阶段。
附:英文原文
Title: Magma accumulation at depths of prior rhyolite storage beneath Yellowstone Caldera
Author: Ross Maguire, Brandon Schmandt, Jiaqi Li, Chengxin Jiang, Guoliang Li, Justin Wilgus, Min Chen
Issue&Volume: 2022-12-02
Abstract: Seismic tomography has provided key insight into Yellowstone’s crustal magmatic system that includes attempts to understand the melt distribution in the subsurface and the current stage of the volcano’s life cycle. We present new tomographic images of the shear wave speed of the Yellowstone magmatic system based on full waveform inversion of ambient noise correlations, which illuminates shear wave speed reductions of greater than 30% associated with Yellowstone’s silicic magma reservoir. The slowest seismic wave speeds (shear wave speed less than 2.3 kilometers per second) are present at depths between 3 and 8 kilometers, overlapping with petrological estimates of the assembly depth of erupted rhyolite bodies. Assuming that Yellowstone’s magmatic system is a crystal mush with broadly distributed melt, we estimate a partial melt fraction of 16 to 20%.
DOI: ade0347
Source: https://www.science.org/doi/10.1126/science.ade0347