Relationship between large earthquakes and volcanic eruptions: A global statistical study

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It is now generally accepted that large earthquakes can promote eruptions at nearby volcanoes. However, the prevalence of “triggered” eruptions, as well as the distance and timescale over which triggering occurs, remain unclear. Here, we use modern global earthquake and eruption records to compare volcanic eruption rates before and after large earthquakes with the time- averaged background eruption rate. We quantify the significance of observed deviations from the average eruption rate using Monte Carlo simulations. To integrate our findings with previous eruption triggering studies, we systematically vary the earthquake magnitudes we consider, as well as the distances and timescales used to calculate eruption rates. We also investigate the effects of earthquake depth and slip orientation. Overall, we find that post-earthquake eruption rates are around 1.25 times the average eruption rate within 750 km and one year following Mw ≥ 7 earthquakes, with above-average post-earthquake eruption rates possibly lasting for two to four years. By contrast, pre-earthquake eruption rates are around 0.9 times the average eruption rate within 750 km and182 days before Mw ≥7 earthquakes. Furthermore, deep earthquakes (≥7 0km) appear to more strongly affect eruption rates than shallow earthquakes, while earthquake slip orientation is also important. Further study of the relationships reported here represents a good opportunity to improve our understanding of tectono-magmatic relationships.