Alteration and deformation of fault-generated pseudotachylytes

我们建议通过结合实验室和实地调查，探索控制伪achylyte蚀变和变形过程的动力学以及相关的微观结构特征，以量化它们保存和识别的可能性。我们将对代表一系列生成场景和蚀变阶段的天然假羟基酸盐和合成模拟材料进行高温高压蚀变和变形实验。实验将提供诊断特征，我们将比较在野外收集的自然断层产生的假木质素的微观结构，以评估其变化历史。考虑到地震的频率和普遍接受的预测大地壳地震共震达到融化条件的震源模型，断层生成的伪岩（一种保留摩擦熔化证据的断层岩石）似乎相对罕见，因此拟议的研究将为伪岩是否实际上很少生成或很少以可识别的形式保存的紧迫问题提供答案。回答这一问题是充分利用现场记录推导震源参数和断层岩石深部性质的必要前提。作为对最近地震的地震学分析的补充，提出的实验和微观结构工作将为地震的能量收支提供独立的约束。

We propose to explore the kinetics of processes that govern the alteration and deformation of pseudotachylyte and associated microstructural characteristics to quantify the likelihood of their preservation and recognition by combining laboratory and field investigations. We will conduct high-temperature, high-pressure alteration and deformation experiments on natural pseudotachylytes and synthetic analogue materials representing a range of generation scenarios and alteration stages. The experiments will provide diagnostic features against which we will compare microstructures of natural fault-generated pseudotachylytes collected in the field to evaluate their alteration history. As fault-generated pseudotachylyte, a type of fault rock that preserves evidence of frictional melting, appears to be relatively rare considering the frequency of earthquakes and commonly accepted source models that predict melting conditions to be coseismically reached for large crustal earthquakes, the proposed study will provide answers to the pressing question whether pseudotachylytes are in fact rarely generated or rarely preserved in a recognizable form. Answering this question is a mandatory prerequisite to fully exploit the field record for the derivation of earthquake-source parameters and the properties of fault rocks at depths. Complementary to seismological analyses of recent earthquakes, the proposed experiments and microstructural work will provide independent constraints on the energy budget of earthquakes.