ASH3D: Ashfall Forecast for Hypothetical Eruption

map showing areas of ash fall

Detailed Description

  • This ashfall graphic is the output of a mathematical model of volcanic ash transport and deposition on the ground (Ash3D, USGS).
  • This model shows expected ashfall accumulation (deposit thickness) for actual or hypothetical eruptions.
  • HVO produces this graphic when a volcano is restless by assuming a reasonable hypothetical eruption, in order to provide a pre-eruptive forecast of areas likely to be affected. During an eruption, HVO updates the forecast with actual observations (eruption start time and duration, plume height) as they become available.
  • Ash3d deposit calculations are calibrated for explosive eruptions in Alaska and are not optimized for the current style of activity at the summit of KÄ«lauea.
  • Colored contour lines represent points of equal ash thickness on the ground. Small accumulations of ash may occur beyond the "Trace" contour. Actual deposit thickness may vary from the forecast as the modelled points are based on our best estimates. Thickness terms are explained here.
  • This graphic does not show ash cloud movement in the atmosphere; please refer to the other graphics for ash cloud forecasts.
  • For more information about ASH3D, see USGS Open-File Report 2013-1122.


Image Dimensions: 665 x 544

Date Taken:

Location Taken: US