EAGER: Investigating the Thermal Maturity of Organic Matter in Fault Zones with Laboratory Experiments

断层力学研究中最难以捉摸的问题之一是断层承受多少剪切应力，这是完整描述断裂过程的必要参数。由于摩擦滑动产生热量，测量断层带高于背景温度的温升可以说明断层的强度。本文描述了一种新的古温度表，它可以通过检测断层内有机分子的热成熟度来建立沉积岩断层的时温历史。该技术广泛应用于石油地球化学中测定地埋热。研究人员将重新利用现有的古温度表，为断裂带建立一个新的古温度表，该古温度表用于确定与埋藏相关的长时间加热。量化断裂带的摩擦加热将使他们能够约束断层和地震参数，如在最大的事件发生时沿断层的剪切应力。为了扩大该古温度计的时温范围，建立断层岩在地震过程中经历的短时间尺度和高温下的热成熟度指标，研究人员将设计并进行与地震加热相关的各种时间和温度组合的富有机质沉积岩快速加热实验，并确定这些反应的短时间尺度动力学参数。同震摩擦的测量对于确定地震扩展为重大社会事件的条件至关重要。这项工作将设计一种直接测量断层滑动摩擦的新方法。此外，还将资助两名早期职业科学家。

One of the most elusive questions in the study of fault mechanics is how much shearstress faults sustain, which is a necessary parameter for a full description of the ruptureprocess. Because frictional slip generates heat, measuring the temperature increase offault zones above background temperatures can elucidates the strength of the fault. Herewe describe a new paleothermometer that can establish time-temperature histories forfaults hosted in sedimentary rocks by examining the thermal maturity of organicmolecules within the fault. This technique is widely applied in petroleum geochemistryto determine burial heating. The investigators will establish a new paleothermometer for fault zones byrepurposing an existing paleothermometer used to establish long duration heatingassociated with burial. Quantifying the frictional heating in a fault zone will allow them toconstrain fault and earthquake parameters like shear stress along a fault during failure andslip of the largest event. In order to extend the time-temperature range of thispaleothermometer and establish thermal maturity indices at the short time scales and high temperatures that fault rocks experience during earthquakes, the investigators will design and conduct rapid heating experiments on organic-rich sedimentary rocks at various combinations of time and temperature relevant to seismic heating and determine the kinetic parameters of these reactions at short time scales.Measurement of the coseismic friction is critical for determining the conditions under which an earthquake can expand into a major, societally significant event. This work will devise a new way to directly measure friction from slip on faults.Furthermore, two early career scientists will be funded.