Megathrust subduction earthquakes generate intense ground shaking and massive tsunami waves, posing major threat to coastal communities. The occurrence of such devastating seismic events is uncertain and depends on their recurrence characteristics (e.g., inter-arrival time distribution and parameters) as well as elapsed time since the last major event. Current standard probabilistic loss models for earthquakes and tsunamis are based on a time-independent Poisson process and uniform earthquake slip distribution. Thereby, considerations of more realistic time-dependent earthquake occurrence and heterogeneous earthquake slip distribution are necessary. This study presents an innovative computational framework for conducting a time-dependent multi-hazard loss estimation of a building portfolio subjected to megathrust subduction earthquakes and tsunamis. The earthquake occurrence is represented by a set of multiple renewal models, which are implemented using a logic-tree approach, whereas earthquake rupture characterization is based on stochastic source models with variable fault geometry and heterogeneous slip distribution. By integrating these hazard components with seismic and tsunami fragility functions, multi-hazard loss potential for a coastal community can be evaluated quantitatively by considering different possibilities of earthquake recurrence and rupture characteristics. To demonstrate the implementation of the developed time-dependent multi-hazard loss model, the Tohoku region of Japan is considered.

大型推力俯冲地震会产生强烈的地震动和海啸，对沿海社区构成重大威胁。此类破坏性地震事件的发生是不确定的，并取决于其复发特征（例如到达时间间隔和参数）以及自上次重大事件以来经过的时间。当前针对地震和海啸的标准概率损失模型基于与时间无关的泊松过程和均匀的地震滑动分布。因此，有必要考虑更现实的时变地震发生和非均质地震滑动分布。这项研究提出了一种创新的计算框架，用于对遭受特大推力俯冲地震和海啸的建筑组合进行随时间变化的多灾种损失估算。地震发生由一组多个更新模型表示，这些模型使用逻辑树方法实现，而地震破裂特征则基于具有可变断层几何形状和非均质滑动分布的随机震源模型。通过将这些危险因素与地震和海啸的脆弱性功能整合在一起，可以通过考虑地震复发和破裂特征的不同可能性来定量评估沿海社区的多灾种损失潜力。为了演示已开发的时间相关的多灾种损失模型的实施，