Wind erosion of volcanic materials in the Hekla area, South Iceland

Abstract

Abstract Iceland has extensive areas with intense aeolian processes, in spite of humid climate. We measured wind erosion in a 110 km2 heterogeneous sandy area near the Mt. Hekla volcano in South Iceland. The area is sparsely vegetated and covered by volcanic materials. Measurements were made during two summer seasons in 2008–2009 with dust traps at 25 locations employing a ‘single dust trap method’ after characterizing sediment height profiles. Sets of electronic equipment that measured wind erosion and several weather parameters were placed at two locations. The results show a large variation in sediment transport with maximum transport in storms ranging from 0 to 1788 kg m−1 at each site and maximum average transport during storm reaching 244 kg m−1 h−1. The aeolian transport each summer ranged from 1 to 2981 kg m−1. Amount of loose sandy sediments on the surface, sediment texture and proximity to water channels are important factors explaining site differences. Wind erosion was most intense in the north-eastern part of the area, with >80% loose sand on the surface but less intense closest to the volcano where coarse pumice characterizes the surface. The research shows a pathway of sediment transport on a landscape scale with north-easterly winds, into the Thjorsa river, enhanced by landscape characteristics and seasonally active water channel. Pumice grains >8 mm in diameter were transported by saltation. Grains >1 mm were commonly >20% of materials collected at 30 cm height, which is explained by low density of the volcanic materials and high wind velocities.