Figure 4From: UK monitoring and deposition of tephra from the May 2011 eruption of Grímsvötn, IcelandSEM analysis of particles of Grímsvötn tephra deposited at Eskdalemuir on 24–25 May. (a) Typical glass shard, diameter ∼40 μ m. The cuspate form indicates fragmentation of vesicular magma. (b) SEM-EDS spectrum for shard shown in (a). The intensity is scaled so that the Si-k α peak is the same size for all samples. There is good agreement with reference samples from proximal locations. (c) Aggregate clast, diameter ∼60 μ m. Component clasts are bubble-wall fragments 1–20 μ m. (d) SEM-EDS spectrum for aggregate clast shown in (c). There is good agreement with reference samples from proximal locations and increased proportions of sodium (Na) and chlorine (Cl).Back to article page