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SEPA studies volcanic imports
Friday 27th May 2011
Figure 1: SEM – particle size range The SEM results show both fine and coarse particles. The fine ash particles seen by SEM showed 'aggregates' or 'clusters' of ash around normal dust/sand particles. The larger particles are mainly quartz, potassium (K)-feldspar and other un determined alumino-silicate minerals which likely come from the immedi ate surrounding environment. The finer particles are present in abundance and consist of highly angular particles, ranging in size from 3 to 10μm.
As the bank holiday looks to be clear of Grimsvotn's fallout, the Scottish Environmental Protection Agency quietly monitors air quality and analyses dust and rainwater samples, looking for volcanic contaminants such as iron, copper, and manganese, while monitoring pH and fluoride levels.
(Left ) Rainfall observers network assists with volcanis ash sample. (Right) Volcanic ash in Lerwick on car door.
On Tuesday 24 May a number of cars in Shetland, Thurso and Orkney were reported to have a covering of dust, suspected to be volcanic ash.
SEPA staff used a piece on clean cloth to collect a sample of this dust from a car in Lerwick, Shetland and sent it to SEPA's laboratory in Aberdeen for analysis.
SEPA asked its colleagues at the James Hutton Institute in Aberdeen to put the sample through more detailed Scanning Electron Microscopy (SEM) to try to determine whether this material was volcanic in nature.
The outcome
Volcanic glass aggregate with concave 'bubble' visible in centre of image.
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