The dynamics of a long-lasting effusive eruption modulated by Earth tides

• Published in: Earth and Planetary Science Letters
• Main Authors: Dumont S., Le Mouel J. -L., Courtillot V., Lopes F., Sigmundsson F., Coppola D., Eibl E. P. S., Bean C. J.
• Other Authors: Le Mouel J.-L., Eibl E.P.S., Bean C.J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Earth tide; effusive eruption; Holuhraun; lava flow; seismic tremor; thermal anomalies; Iceland
• Online Access: http://hdl.handle.net/2318/1770059; https://doi.org/10.1016/j.epsl.2020.116145

Deciphering eruptive dynamics in near-real time is essential when dealing with hazard assessment and population evacuation. Recognition of specific patterns in time-series measured during volcanic activity may help decipher distinctive behavior at active volcanoes, providing insights into the underlying driving mechanisms. Multi-parameter data sets usually agree on the overall trend characterizing the temporal evolution of an eruption providing insights into the first-order eruptive dynamics. However, second-order variations detected in different data sets remain often poorly understood. The 2014-2015 Holuhraun eruption (Iceland) offers an excellent opportunity to investigate the dynamics of a long-lasting effusive eruption. We analyze the seismic tremor and the volcanic radiated power emitted by the lava field during the 6 months of the eruption using Singular Spectrum Analysis (SSA). In both geophysical time-series, we identify periods from ∼5 to ∼32 days coinciding with periods of Earth tides. Here we show that ∼50% of both signals are composed of tidal periods suggesting that magma movements follow frequencies imposed by lunisolar forces within the crust and at Earth's surface.