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能承受多大的剪应力，这是全面描述破裂过程所必需的参数。由于摩擦滑动产生热，测量高于背景温度的超高区的温升可以阐明断层的强度。在这里，我们描述了一种新的古温度计，它可以通过检测断层内有机分子的热成熟度来建立存放在沉积岩中的断层的时间-温度历史。这项技术在石油地球化学中被广泛应用于确定埋藏加热。研究人员将通过改变现有的古温度计的用途来建立一个新的断裂带古温度计，该古温度计用于建立与埋藏相关的长时间加热。量化断层带中的摩擦热将允许他们约束断层和地震参数，如在最大事件的破坏和滑动期间沿断层的剪应力。为了扩大这种古温度计的时间-温度范围，并在地震过程中断层岩经历的短时间尺度和高温下建立热成熟度指数，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含有机质的沉积岩的快速加热实验，并在短时间尺度上确定这些反应的动力学参数。测量同震摩擦对于确定地震可能扩展为重大社会事件的条件至关重要。这项工作将设计出一种直接测量断层滑动摩擦的新方法。此外，两名早期职业科学家将获得资助。

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.