Field-based measurements of volcanic ash resuspension by wind

TY - JOUR

T1 - Field-based measurements of volcanic ash resuspension by wind

AU - Del Bello, E.

AU - Taddeucci, J.

AU - Merrison, Jonathan P.

AU - Rasmussen, Keld Rømer

AU - Andronico, D.

AU - Ricci, T.

AU - Scarlato, P.

AU - Iversen, Jens Jacob

PY - 2021/1

Y1 - 2021/1

N2 - The resuspension of volcanic ash by wind is a significant source of hazard during and after volcanic eruptions. Parameterizing and modeling ash resuspension requires direct measurement of the minimum wind shear stress required to move particles, usually expressed as the threshold friction velocity U ⁎ th, a parameter that, for volcanic ash, has been measured only scarcely and always in the laboratory. Here, we report the first field measurements of U ⁎ th for volcanic ash, with a portable wind tunnel specifically developed, calibrated, and tested. Field measurements, performed on natural reworked ash deposits from Sakurajima (Japan) and Cordón Caulle (Chile) volcanoes, agree well with our laboratory determinations on ash from the same deposits, with values of U ⁎ th ranging from 0.13 to 0.38 m/s. Our results show that the median grain size of the deposit and particle shape have a stronger control on U ⁎ th than the local substratum nature and deposit texture.

AB - The resuspension of volcanic ash by wind is a significant source of hazard during and after volcanic eruptions. Parameterizing and modeling ash resuspension requires direct measurement of the minimum wind shear stress required to move particles, usually expressed as the threshold friction velocity U ⁎ th, a parameter that, for volcanic ash, has been measured only scarcely and always in the laboratory. Here, we report the first field measurements of U ⁎ th for volcanic ash, with a portable wind tunnel specifically developed, calibrated, and tested. Field measurements, performed on natural reworked ash deposits from Sakurajima (Japan) and Cordón Caulle (Chile) volcanoes, agree well with our laboratory determinations on ash from the same deposits, with values of U ⁎ th ranging from 0.13 to 0.38 m/s. Our results show that the median grain size of the deposit and particle shape have a stronger control on U ⁎ th than the local substratum nature and deposit texture.

KW - Cordon Caulle volcano

KW - Sakurajima volcano

KW - detachment threshold

KW - volcanic ash

KW - wind resuspension

KW - wind tunnel

UR - http://www.scopus.com/inward/record.url?scp=85097579407&partnerID=8YFLogxK

U2 - 10.1016/j.epsl.2020.116684

DO - 10.1016/j.epsl.2020.116684

M3 - Journal article

SN - 0012-821X

VL - 554

JO - Earth and Planetary Science Letters

JF - Earth and Planetary Science Letters

M1 - 116684

ER -