Is There an Influence of the Pole Tide on Volcanism? Insights From Mount Etna Recent Activity

Abstract

We investigate a possible link between polar motion and (i) seismic energy release and (ii) timing and intensity of eruptions at Mount Etna (Italy) for which a dense observational database is available. Our study suggests that the seismicity around Mount Etna increases during the largest excursions of the Earth rotation pole, which result from the constructive interference of the climate-driven seasonal and Chandler wobbles. To a lesser extent, a similar link is detected between the pole tide and the erupted volume of magma. We infer that, by creating periodic changes in the state of stress in the crust through a variable centrifugal force and a periodic vertical displacement (pole tide), variations in polar motion influence eruption timing and magnitude and the rate of seismic energy release from volcanoes. This study provides new evidences on the sensitivity of volcanoes to external forcing. Plain Language SummaryThe Earth surface is continuously deformed by a wide range of phenomena including lunisolar tides and centrifugal forces due to changes in the Earth's rotation rate and in the direction of its rotation axis. The latter class of deformations is typically of a centimeter on interannual timescales. On another side, some volcanoes appear to be sensitive to small perturbations of the crustal stress. We detected similar variability in the centrifugal forces arising from the Earth's rotation axis direction variability and Mount Etna seismicity and erupted magma volume. This suggests that the variation of the Earth's rotation axis direction plays a significant role as modulator of the activity of Mount Etna.

On the Link Between Global Volcanic Activity and Global Mean Sea Level

“…Complementary approaches will be necessary for better understanding this link, as for instance, numerical modeling to investigate how tidal stresses can destabilize magma chambers and fault systems (McNutt and Beaven, 1987;Ide et al, 2016;Jonhson et al, 2017;Scholz, 2019). Moreover, the impact of the fluctuations of the Earth's rotation axis on volcanic eruptions was also suggested locally and regionally (Kutterolf et al, 2013;Lambert and Sottili, 2019).…”

Tides and Volcanoes: A Historical Perspective

“…From a regional to a global scale, increasing evidence for common cycles in the volcanological, biological and astronomical-orbital events includes a remarkable synchronism with Milankovitch cycles, which strongly influenced the Earth's climatic patterns (Kutterolf et al, 2013;Kutterolf et al, 2019;Puetz et al, 2014). On a broader perspective, beyond the high-frequency (from semi-diurnal to fortnightly) tidal forcing of volcanic and seismic activities, low-frequency rotational tides (i.e., pole tide and fluctuations in the Length of Day, LOD) are claimed as major controlling factors for a variety of tectonic and volcanic processes acting both at a local (Lambert and Sottili, 2019) and at a global scale (Palladino and Sottili, 2014;Sottili et al, 2015). Specifically, a recent field of research is devoted to understanding how long-period rotational tide (i.e, monthly to multiyear pole tides and LOD changes) acts on volcanoes, as short-periodic (commonly semi-diurnal to fortnightly tides) forcing influences shallow volatile-saturated magma reservoir or hydrothermal environments (Sottili et al, 2007;Sottili and Palladino, 2012;Petrosino et al, 2018) whilst low-frequency, rotational tidal oscillations are compatible with the resonance time of the lithosphere (Zaccagnino et al, 2020) and with differential stress changes on wall rocks of magma chambers located within the shallow 20 km of the Earth's crust (Sottili et al, 2015;Lambert and Sottili, 2019).…”

“…On a broader perspective, beyond the high-frequency (from semi-diurnal to fortnightly) tidal forcing of volcanic and seismic activities, low-frequency rotational tides (i.e., pole tide and fluctuations in the Length of Day, LOD) are claimed as major controlling factors for a variety of tectonic and volcanic processes acting both at a local (Lambert and Sottili, 2019) and at a global scale (Palladino and Sottili, 2014;Sottili et al, 2015). Specifically, a recent field of research is devoted to understanding how long-period rotational tide (i.e, monthly to multiyear pole tides and LOD changes) acts on volcanoes, as short-periodic (commonly semi-diurnal to fortnightly tides) forcing influences shallow volatile-saturated magma reservoir or hydrothermal environments (Sottili et al, 2007;Sottili and Palladino, 2012;Petrosino et al, 2018) whilst low-frequency, rotational tidal oscillations are compatible with the resonance time of the lithosphere (Zaccagnino et al, 2020) and with differential stress changes on wall rocks of magma chambers located within the shallow 20 km of the Earth's crust (Sottili et al, 2015;Lambert and Sottili, 2019). Moreover, over the last years, the detection of Milankovitch periodicities in volcanic explosive activity through the Pleistocene-Holocene (Kutterolf et al, 2013(Kutterolf et al, , 2019Praetorius et al, 2016) led to the formulation of a variety of hypotheses on the possible cause-and-effect relationships among orbital forcing, climate changes and volcanism.…”

Long-Term Forecasting of Strong Earthquakes in North America, South America, Japan, Southern China and Northern India With Machine Learning

“…For example, even the Sun's activity has been suggested as a significant agent causing earthquakes (Anagnostopoulos et al, 2021). Other proximate causes discussed in the literature include pole tide (Shen et al, 2005), pole wobble (Lambert and Sottili, 2019), surface ice and snow loading (Heki, 2019), glacial isostatic rebound (Hampel et al, 2007), heavy precipitation (Hainzl et al, 2006), atmospheric pressure (Liu et al, 2009), sediment unloading (Calais et al, 2016), seasonal groundwater change (Tiwari et al, 2021), seasonal hydrological loading (Panda et al, 2020). In addition, the Earth's rotation and tidal spinning have also been suggested as driver of plate tectonic activity.…”