Modulation of Popocatépetl’s activity by regional and worldwide earthquakes

Volcanoes switching from quiescence to eruption shortly after catastrophic earthquakes have raised interest for volcanic triggering and the influence of earthquakes on volcanic activity. Its influence on already active systems and especially at open-vent volcanoes is more difficult to apprehend. A number of recent observations suggest an influence of tectonic earthquakes on Popocatepetl's activity, the importance of which remains unknown. To further investigate this, we introduce an index, based on the near-field concept, identifying the earthquakes with the highest potential to promote volcanic activity (hereafter termed "significant earthquakes"). The time series of significant earthquakes is compared with the intensity of the volcanic activity, as characterized by the number and energy of volcano-tectonic earthquakes, the number of dome extrusions, the intensity of thermal and degassing fluxes, and ash production. Three main periods with contrasting activity stand out showing that Popocatepetl presents intense activity when significant tectonic earthquakes are frequent. Enhanced extrusion apparently follows significant earthquakes quickly with pulses of dome extrusion that peak after 1.3 +/- 0.3 years. Conversely, extrusive activity vanishes when significant seismicity disappears, as during the period 2003-2011, which coincides with a 12-year-long significant seismicity gap. Hence, we propose that the 1994-2022 open-vent activity at Popocatepetl is in part modulated by the repetitive occurrence of significant earthquakes that periodically promote volcanic activity.