Volcanic ash leaching as a means of tracing the environmental impact of the 2011 Grímsvötn eruption, Iceland

Abstract

The Grímsvötn volcanic eruption, from 21 to 28 May, 2011, was the largest eruption of the Grímsvötn Volcanic System since 1873, with a Volcanic Explosivity Index (VEI) of magnitude 4. The main geochemical features of the potential environmental impact of the volcanic ash-water interaction were determined using two different leaching methods as proxies (batch and vertical flow-through column experiments). Ash consists of glass with minor amounts of plagioclase, clinopyroxene, diopside, olivine and iron sulphide; this latter mineral phase is very rare in juvenile ash. Ash grain morphology and size reflect the intense interaction of magma and water during eruption. Batch and column leaching tests in deionised water indicate that Na, K, Ca, Mg, Si, Cl, S and F had the highest potential geochemical fluxes to the environment. Release of various elements from volcanic ash took place immediately through dissolution of soluble salts from the ash surface. Element solubilities of Grímsvötn ash regarding bulk ash composition were <1 %. Combining the element solubilities and the total estimated mass of tephra (7.29 × 10(14) g), the total inputs of environmentally important elements were estimated to be 8.91 × 10(9) g Ca, 7.02 × 10(9) g S, 1.10 × 10(9) g Cl, 9.91 × 10(8) g Mg, 9.91 × 10(8) g Fe and 1.45 × 10(8) g P The potential environmental problems were mainly associated with the release of F (5.19 × 10(9) g).

Agriculture and forestry impact assessment for tephra fall hazard

“…In order to create a fluoride toxicity coefficient, points with high fluoride concentrations (>150 mg/kg) were excluded from the creation of fragility functions [Cronin et al 1997;Armienta et al 2011;Ayris and Delmelle 2012;Cronin et al 2014;Cabré et al 2016;Stewart et al 2016]. Large, high intensity pastoral fragility points with low fluoride concentrations were then subtracted from high fluoride points for each thickness band to give the coefficient.…”

Variations in tephra stratigraphy created by small‐scale surface features in sub‐polar landscapes

“…Thickness measurements collected by Cabré et al . (2016) from Skeiðarársandur (49 km from the volcanic vent and ~20 km from Kálfafell) ranged from 5 to 250 mm.…”

“…The interaction between glacial meltwater and magma initiated a phreatomagmatic style eruption. The eruption was short-lived, but intense, with a Volcanic Explosivity Index Magnitude of 4 (Guðmundsson et al 2012;Cabr e et al 2016). The eruption generated a total (bulk) volume of tephra of 0.7 km 3 (Guðmundsson et al 2012) and had a plume height of <20 km (Horwell et al 2013).…”

“…2012; Cabré et al . 2016). The eruption generated a total (bulk) volume of tephra of 0.7 km 3 (Guðmundsson et al .…”

Bubbles and Dust: Experimental Results of Dissolution Rates of Metal Salts and Glasses From Volcanic Ash Deposits in Terms of Surface Area, Chemistry, and Human Health Impacts

“…Milli-Q water was used as the leaching solute, and the columns rested in a thermostatic water bath of 25 ±0.2°C. The Milli-Q source water passed through the columns at a rate of 0.28 ±0.1 ml/min, based on previous CLT studies (Cabré et al, 2016;Chichester and Landsberger, 2012;Escudey et al, 2014;Frogner et al, 2001;Taylor & Lichte, 1980;Witham et al, 2005). Columns were positioned vertically so that source water entered through the bottom of the column allowing any air pockets to escape.…”