Njord Seminar with Shyam Nandan

Njord Seminar with Shyam Nandan (ETH Zurich): "Triggering of large earthquakes is driven by their twins"

A poster for a Njord seminar showing presenter, title, date, Njord seal, and Zoom link.


Fundamentally related to the ultraviolet (UV) divergence problem in Physics, conventional wisdom in seismology is that the smallest earthquakes, which are numerous and often go undetected, dominate the triggering of major earthquakes, making accurate forecasting of the latter difficult if not inherently impossible. Using the general class of epidemic type aftershock sequence (ETAS) models and rigorous pseudo-prospective experiments, we show that ETAS models that feature a specific magnitude correlation between triggered and triggering earthquakes and a magnitude-dependent Omori kernel, significantly outperform simpler ETAS models, in which these features are absent. Using the best forecasting model, we then show that large earthquakes are preferentially triggered by large events. These findings have far-reaching implications for short-term and medium-term seismic risk assessment, as well as for the development of a deeper theory without UV cut-off that is locally self-similar.

The corresponding paper with a different title is under revision now. The last version of it can be found at the following link: https://www.essoar.org/doi/abs/10.1002/essoar.10510831.1 

You will find the complete schedule for Njord Seminar Series spring '22 here.

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Published Apr. 19, 2022 3:05 PM - Last modified Apr. 19, 2022 3:05 PM