Properties of dust source material and volcanic ash in Iceland

Abstract

The volcanic origin, primarily basaltic, of most of the surface material in Iceland influences its physical properties and appearance. Size distributions, shape analyses and melting experiments were made for surface material collected in high‐erosion dust source areas and fresh volcanic ash deposits to determine whether they differ from one another and from dust from other major dust sources. The major differences found between Icelandic dust and dust from other major dust sources in the world, such as the Sahara, are in the particle shapes, lower density and darker colour. Icelandic dust particles greater than 20 μm retain volcanic morphological properties that are also found in fresh volcanic ash. Dust and fresh volcanic ash particles less than 20 μm are crystalline and blocky in nature, similar to the dust from other global source regions. The finer grained (<20 μm) Icelandic particles will have similar suspension and transport behaviours and be similarly hazardous to health and infrastructure as non‐Icelandic dust. The coarser particles (>20 μm) will have different suspension and transport behaviours than other dusts due to the volcanic morphology. Icelandic surface material has between 5% and 30% glassy particles compared to fresh volcanic ash which has more than 50% glassy particles. Glassy particles were observed to melt at a lower temperature than the mineral grains; and, as a result, volcanic ash is found to be more threatening to aircraft engines than the typical dust from Iceland. Icelandic dust was observed to be blocky, or plate‐like in the respirable size fraction, suggesting similar health hazards as dust from other regions.

Wind Tunnel‐Based Comparison of PM10 Emission Rates for Volcanic Ash and Glaciogenic Aerosol Sources Within Iceland

“…There is no clear dependency on the sample origin in this regard. This result is consistent with the suggestion that during saltation, impulse forces during particle impact with the bed surface are sufficient to rupture and eject the dust coats adhering to the external surface, within the pores, and along fractured edges of the particles as shown by Mockford (2017) and suggested by Butwin et al (2020). The total amount of suspended particulate (TSP), as sampled with the DustTrak (model 8,530), is mostly composed of PM 10 (>94%) with the exception of Glacio 1 at 86%.…”

Monitoring Dust Events Using Doppler Lidar and Ceilometer in Iceland

“…Unlike the June case, the wind in the morning of 31 July was easterly ( Figure 10), and combining the HYSPLIT and weather conditions, the origin of the dust is considered to be from the west of the Icelandic highlands, on the west of Vatnajokull glacier, the largest ice cap in Iceland (Figure 1, location D). The western highlands are also a common source of Icelandic dust [18,27,55]. PM 10 and PM 2.5 concentration in Reykjavik were high from the afternoon of 31 July.…”

“…The origins of both dust event, Lake Hagavatn (June case) and the Western Highlands (July case) are severe erosional areas and common source locations for dust in Iceland [18]. Lake Hagavatn is a dry glacial lake, characterized by more crystalline materials than the volcanic glass that makes up most other Icelandic dust, while the Western Highlands area is covered with silty sediments as well as volcanic materials, and the particles are more spherical than other volcanic ash [18,55]. Figure 16 shows the size distribution measured by the sun-photometer.…”

Aeolian Remobilisation of Volcanic Ash: Outcomes of a Workshop in the Argentinian Patagonia

“…Resuspended ash emitted in September 2013 and April 2017 in Iceland rose up to 2 km due to a temperature inversion (Beckett et al, 2017;Hammond and Beckett, 2019), whereas that from the 2020 Taal eruption, the Philippines (NDRRMC, 2020), and ancient pyroclastic material in the Fiambalá Basin, Argentina (Mingari et al, 2017), have reached 5-6 km. Furthermore, the greater abrasivity and lower softening point of ash (≥700°C) compared to mineral dust (Kueppers et al, 2014) means that ash can potentially damage hot engines more than other remobilised material (Müller et al, 2019;Butwin et al, 2020).…”