Intrusion triggering of the 2010 Eyjafjallajökull explosive eruption

Abstract

Gradual inflation of magma chambers often precedes eruptions at highly active volcanoes. During such eruptions, rapid deflation occurs as magma flows out and pressure is reduced. Less is known about the deformation style at moderately active volcanoes, such as Eyjafjallajökull, Iceland, where an explosive summit eruption of trachyandesite beginning on 14 April 2010 caused exceptional disruption to air traffic, closing airspace over much of Europe for days. This eruption was preceded by an effusive flank eruption of basalt from 20 March to 12 April 2010. The 2010 eruptions are the culmination of 18 years of intermittent volcanic unrest. Here we show that deformation associated with the eruptions was unusual because it did not relate to pressure changes within a single magma chamber. Deformation was rapid before the first eruption (>5 mm per day after 4 March), but negligible during it. Lack of distinct co-eruptive deflation indicates that the net volume of magma drained from shallow depth during this eruption was small; rather, magma flowed from considerable depth. Before the eruption, a ∼0.05 km(3) magmatic intrusion grew over a period of three months, in a temporally and spatially complex manner, as revealed by GPS (Global Positioning System) geodetic measurements and interferometric analysis of satellite radar images. The second eruption occurred within the ice-capped caldera of the volcano, with explosivity amplified by magma-ice interaction. Gradual contraction of a source, distinct from the pre-eruptive inflation sources, is evident from geodetic data. Eyjafjallajökull's behaviour can be attributed to its off-rift setting with a 'cold' subsurface structure and limited magma at shallow depth, as may be typical for moderately active volcanoes. Clear signs of volcanic unrest signals over years to weeks may indicate reawakening of such volcanoes, whereas immediate short-term eruption precursors may be subtle and difficult to detect.

Composition and evolution of volcanic aerosol from eruptions of Kasatochi, Sarychev and Eyjafjallajökull in 2008–2010 based on CARIBIC observations

“…To further investigate this component of the aerosol it was compared to the composition of a fall-out sample of volcanic ash from the eruption site (Sigmundsson et al, 2010). The composition of erupted material can change over time and also with distance from the source due to fractionation and sedimentation (Carey and Sigurdsson, 1982).…”

“…The mass of sulphate (SO 4 ) was calculated by adding the amount of oxygen corresponding to the measured mass of sulphur, assuming that all sulphur is in the form of SO 4 . In a similar manner the mass of the ash components in the Eyjafjallajökull samples were obtained by adding the mass of oxygen according to the fallout sample presented in the table by Sigmundsson et al (2010). Elements found in ash that could not be detected, primarily sodium (Na), magnesium (Mg), aluminum (Al) and phosphorus (P), were calculated according to the composition of the fallout sample using the relation to the iron content.…”

Degradation of Thermal Barrier Coatings from Deposits and Its Mitigation

“…For comparison, the chemical compositions of the CMAS sand [19] and the Eyjafjallajökull volcanic ash [36] from previous studies are also included in Table 1. Figures 2B, 2C, 2D, and 2E are corresponding EDS elemental maps of Si, Ca, Fe, and Zr, respectively.…”

Remote Sensing of Volcanic Hazards and Their Precursors

“…3. Together with Global Positioning System (GPS) geodetic measurements of deformation, the interferograms showed a period of inflation prior to eruption, which could be fit with a series of sills at 4-6 km depth and a dike extending almost to the surface, evolving in the volcano subsurface over three months prior to the eruption [24]. On March 20th the dike breached the surface through a narrow channel feeding the flank eruption.…”