Seismo Lab Brown Bag Seminar

The energy-moment ratio of large earthquakes plays a critical role in determining their destructiveness. The energy-moment ratio of global earthquakes varies by orders of magnitude, yet the underlying controlling factors remain poorly understood. Here, we demonstrate that high-frequency energy radiation in large earthquakes correlates with the spatial complexity of their rupture processes. We introduce a measure of rupture complexity based on the distribution of aftershocks. An analysis of 10 globally distributed moderate-to-large strike-slip earthquakes reveals that greater rupture complexity produces higher energy radiation efficiency. In addition, we find that the measured rupture complexity correlates with the fault size-frequency distribution within a fractal system. Our findings highlight the improvement from incorporating rupture complexity beyond simple planar fault models when modeling energy radiation. If faulting complexity can be estimated for source regions from ongoing seismicity, it would serve to improve regional seismic hazard forecasts.