Increment in the volcanic unrest and number of eruptions after the 2012 large earthquakes sequence in Central America

Gino González,Aaron Moya,Takumi Hayashida,Bunichiro Shibazaki,Federico Lucchi,Giovanni Chiodini,Joan Martí,Karoly Nemeth,Eisuke Fujita,Dmitri Rouwet,Gustavo Chigna,Raúl Mora-Amador,Izumi Yokoyama

doi:10.1038/s41598-021-01725-1

Abstract

Understanding the relationship cause/effect between tectonic earthquakes and volcanic eruptions is a striking topic in Earth Sciences. Volcanoes erupt with variable reaction times as a consequence of the impact of seismic waves (i.e. dynamic stress) and changes in the stress field (i.e. static stress). In 2012, three large (Mw ≥ 7.3) subduction earthquakes struck Central America within a period of 10 weeks; subsequently, some volcanoes in the region erupted a few days after, while others took months or even years to erupt. Here, we show that these three earthquakes contributed to the increase in the number of volcanic eruptions during the 7 years that followed these seismic events. We found that only those volcanoes that were already in a critical state of unrest eventually erupted, which indicates that the earthquakes only prompted the eruptions. Therefore, we recommend the permanent monitoring of active volcanoes to reveal which are more susceptible to culminate into eruption in the aftermath of the next large-magnitude earthquake hits a region.

Highlights

Understanding the relationship cause/effect between tectonic earthquakes and volcanic eruptions is a striking topic in Earth Sciences
This study investigates the unique occurrence of three major earthquakes in Central America, generated by the subduction of the Cocos plate beneath the Caribbean plate, over a period of just 72 days in 2012 (August 27, El Salvador, Mw = 7.3; September 5, Costa Rica, Mw = 7.6; November 7, Guatemala, Mw = 7.4) and how these earthquakes affected the state of unrest or eruption in the volcanoes of the region
In the period of 2000–2019, 51 volcanic eruptions with a Volcanic Explosive Index[30] (VEI) ≥ 2 occurred in Central America, of which 21 were from before the three large 2012 earthquakes and 30 were afterwards (Fig. 2a; see Supplementary Material, Table S5)

Summary

Introduction

Understanding the relationship cause/effect between tectonic earthquakes and volcanic eruptions is a striking topic in Earth Sciences. Other studies discussed that volcanoes will tend to erupt in the medium-to-long term, that is, months, years or even decades after the earthquakes[7,9,21,22,23] These longer reaction times can be explained by (1) the co-seismic pressure change in the stress field around the volcano or in the magma system, known as static s tress[7,8,9] and/or in the case of giant megathrust earthquakes in convergent tectonic systems by (2) the viscoelastic relaxation of the mantle and its effect on the magmatic system. Recent research has proposed that an earthquake alone is not enough to trigger an eruption, if the magmatic system is not ready to e rupt[8,24,25]

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