Systematic fluctuations in the global seismic moment release

Ilya Zaliapin, & Corné W. Kreemer

Published 2017, SCEC Contribution #6265

We revisit the significance of the increased number of great earthquakes since 2005. Analysis of the global moment release during 1918–2012 shows that neither tapered nor doubly truncated Pareto model with time-independent parameters can satisfactorily explain the observations, suggesting decreased moment release during 1975–2004. A model-independent analysis, by resampling the observed moments, also indicates a lower level of the moment release during this period. Our results suggest the existence of temporal variation in the seismic moment distribution on a global scale. The post-2004 observations signify a transition to a regime with increased moment release. We argue that our conclusions remain valid for alternative choices of moment distribution and its parameterization, as long as a model is consistent with available data. The analysis uses sequential order of events but not their occurrence times, and hence the results are independent of a particular model for the earthquake occurrence times.

Zaliapin, I., & Kreemer, C. W. (2017). Systematic fluctuations in the global seismic moment release. Geophysical Research Letters, 44(10), 4820-4828.