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Correlations between earthquake magnitude and early features of rupture in a global dataset
  • Rebecca Louise Colquhoun,
  • Jessica Cleary Hawthorne
Rebecca Louise Colquhoun
University of Oxford

Corresponding Author:[email protected]

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Jessica Cleary Hawthorne
Department of Earth Sciences, University of Oxford
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Abstract

It remains uncertain whether an earthquake ”knows” its final magnitude part-way through its rupture. Several studies have found that early features of rupture can constrain final earthquake magnitude, but many of these have considered datasets with fewer than 100 earthquakes in order to reduce extraneous sources of variability. We consider a larger, but less carefully curated dataset. We calculate four parameters of the early portions of seismograms using $>$4000 earthquakes from around the world; we simply accept the scatter inherent in such a range of events. Despite this scatter, we find that on average larger earthquakes have distinct features in their early stages: they have longer predominant and average periods, release more energy, and reach higher maximum moment rates. The differences between small and large earthquakes persist even when we consider short measurement windows less than 1/3 of the earthquake duration. These results further evidence that there are physical differences between the early stages of large and small earthquakes. These, and further observations, could help us better understand how local stresses and frictional weakening drive earthquake rupture.
14 Aug 2024Submitted to ESS Open Archive
14 Aug 2024Published in ESS Open Archive