Distal deposition of tephra from the Eyjafjallajökull 2010 summit eruption

Abstract

The 2010 Eyjafjallajökull lasted 39 days and had 4 different phases, of which the first and third (14–18 April and 5–6 May) were most intense. Most of this period was dominated by winds with a northerly component that carried tephra toward Europe, where it was deposited in a number of locations and was sampled by rain gauges or buckets, surface swabs, sticky‐tape samples and air filtering. In the UK, tephra was collected from each of the Phases 1–3 with a combined range of latitudes spanning the length of the country. The modal grain size of tephra in the rain gauge samples was 25 μm, but the largest grains were 100 μm in diameter and highly vesicular. The mass loading was equivalent to 8–218 shards cm−2, which is comparable to tephra layers from much larger past eruptions. Falling tephra was collected on sticky tape in the English Midlands on 19, 20 and 21st April (Phase 2), and was dominated by aggregate clasts (mean diameter 85 μm, component grains <10 μm). SEM‐EDS spectra for aggregate grains contained an extra peak for sulphur, when compared to control samples from the volcano, indicating that they were cemented by sulphur‐rich minerals e.g. gypsum (CaSO4⋅H2O). Air quality monitoring stations did not record fluctuations in hourly PM10 concentrations outside the normal range of variability during the eruption, but there was a small increase in 24‐hour running mean concentration from 21–24 April (Phase 2). Deposition of tephra from Phase 2 in the UK indicates that transport of tephra from Iceland is possible even for small eruption plumes given suitable wind conditions. The presence of relatively coarse grains adds uncertainty to concentration estimates from air quality sensors, which are most sensitive to grain sizes <10 μm. Elsewhere, tephra was collected from roofs and vehicles in the Faroe Islands (mean grain size 40 μm, but 100 μm common), from rainwater in Bergen in Norway (23–91 μm) and in air filters in Budapest, Hungary (2–6 μm). A map is presented summarizing these and other recently published examples of distal tephra deposition from the Eyjafjallajökull eruption. It demonstrates that most tephra deposited on mainland Europe was produced in the highly explosive Phase 1 and was carried there in 2–3 days.

A new scheme for sulphur dioxide retrieval from IASI measurements: application to the Eyjafjallajökull eruption of April and May 2010

“…Between 3-5 May an increase in seismic activity was followed by a more intense explosive eruptions. The discharge rate increased and was highly variable (Stevenson et al, 2012). Ash production increased and the eruption column altitude was between 4 and 10 km .…”

“…During this period the injection altitude of the plume is estimated at between 2 and 10 km (Marzano et al, 2011;Stohl et al, 2011) and the wind conditions transported the ash plume in a SE direction, towards Europe (Petersen et al, 2012). This was the most powerful phase of the eruption with the highest mass discharge rate (Stevenson et al, 2012). The majority of the tephra deposited in Europe was produced in this phase (Stevenson et al, 2012).…”

“…This was the most powerful phase of the eruption with the highest mass discharge rate (Stevenson et al, 2012). The majority of the tephra deposited in Europe was produced in this phase (Stevenson et al, 2012).…”

“…Following earthquake activity an explosive eruption began on the 14 April 2010. The explosive part of the eruption can be divided into three phases (Zehner, 2012;Stevenson et al, 2012;Petersen et al, 2012):…”

Construction of volcanic records from marine sediment cores: A review and case study (Montserrat, West Indies)

“…For example, some fallout deposits may fall outside the defined field in Figure 6 if they are poorly-sorted as a result of ash transportation at different levels in the atmosphere with differing wind trajectories, as in the 1991 Pinatubo eruption (Wiesner et al, 2004). Furthermore, aggregation of clasts of varying sizes commonly occurs in plumes from large explosive eruptions, leading to less wellsorted fallout deposits, which are commonly bimodal and contain a fine ash mode derived from aggregation (Carey and Sigurdsson, 1982;Rose and Durant, 2011;Stevenson et al, 2012;Brown et al, 2012). For the volcaniclastic deposits deemed as non-tephra-fallout deposits, this does not necessarily preclude the presence of some primary tephra-fallout grains as these are average values, and the comminution processes occurring in co-ignimbrite plumes, for example, may plot outside our defined tephra-fallout field.…”