Ash3d

Volcanic Ash Dispersion Model

The Ash3d Volcanic Ash Dispersion Model

During explosive eruptions, volcanic ash can disrupt downwind populations by causing breathing problems, clogging air filters, shorting out power systems and making transportation difficult. Volcanic ash clouds can threaten air traffic by sandblasting windscreens, clogging pitot tubes, and in severe cases, causing jet engines to shut down.

Before and during eruptions, it is important to anticipate where ash clouds might move and deposits might fall. For this purpose, the U.S. Geological Survey has developed the Ash3d model. Ash3d uses three-dimensional, time-varying wind fields and other meteorological properties from numerical weather prediction models to calculate where airborne ash is transported under current or historical atmospheric conditions. Results are used in several ways.

When volcanoes threaten to erupt, the USGS runs daily simulations to anticipate where ash clouds may move or deposits might land. Model results are publicly posted, for example, at the Alaska Volcano Observatory.

2006 Satellite image of Cleveland volcano ash plume.

Ash plume drifting downwind from Cleveland Volcano, Alaska on May 3, 2006. Public photo taken from the International Space Station.

Cleveland volcano daily simulations image.

To understand volcanic processes and improve our forecasting capability, we simulate historical eruptions such as those at Mount St. Helens in 1980 or Redoubt, Alaska, in 2009. We test our predictive capability by systematic comparison with observed ash clouds or deposits. We work to improve Ash3d by adding volcanic processes, like the growth of umbrella clouds during large eruptions, or the aggregation and fallout of fine ash.

Image showing progression of volcanic ash.

To assist other scientists. Ash3d is used by dozens of scientists around the world, in volcano observatories, government agencies, and universities, to improve understanding of ash-producing volcanic processes and associated hazards.

Appropriate Use. We do not support the use of Ash3d to produce official hazard assessment or forecast products without express permission and collaboration with the USGS. Contact us at the links below for more information.

Ash3d is documented and tested through a series of scientific papers. Selected ones are listed on our resources page.