How Do Earthquakes Generate Extreme Ground Accelerations?

这项研究将分析地震模型，以解释在某些情况下如何预期极端的地面加速度。过去二十年记录的地震强烈地面运动数据明确表明，地面加速度可以超过1.0 g （1 g是地球表面的重力加速度），在某些情况下可以超过2.0 g。考虑到许多分析对峰值加速度的限制值较小，这些加速度确实是惊人的。这些极端的加速度是不寻常的，因为附近的加速度计不会同时记录类似的峰值振幅。极端加速度将使用地震破裂历史的运动学模型进行分析，该模型结合了滑动分布和传播破裂锋的时间依赖性。在根据地震的运动学描述确定关键参数之后，分析将扩展到包含地震的动力学，以确保运动学模型在物理上是可实现的。

This research will analyze earthquake models to explain how extreme ground accelerations can be expected under certain circumstances. Earthquake strong ground motion data recorded over the past two decades have unequivocally shown that ground acceleration can exceed 1.0 g (one g is the acceleration of gravity at the surface of the earth) and in some cases 2.0 g. These accelerations are truly spectacular given that many analyses place smaller limiting values on peak acceleration. These extreme accelerations are unusual in that nearby accelerometers do not simultaneously record similar peak amplitudes. The extreme accelerations will be analyzed using a kinematic model of the earthquake rupture history that incorporates both the distribution of slip and the time dependence of the propagating rupture front. After determining the critical parameters based on the kinematic description of the earthquake, the analysis will be extended to incorporate the dynamics of an earthquake to ensure that the kinematic models are physically realizable.