Three-dimensional dynamic model to analyze volcanic explosions
A 3-D model of a volcanic explosion, based on the 1980 eruption of Mount St. Helens in Washington state, can improve scientific knowledge of how to trigger some volcanic explosions, and help identify areas where there is more likely that an explosion of such characteristics as an international team of volcanologists.
Mount St. Helens began a catastrophic eruption on May 18, 1980, producing a lateral blast of low angle, with unusual force and a high content of particles. The explosion lasted less than five minutes, but caused severe damage to about 600 square miles, killing 57 people and destroying 250 homes and 47 bridges. Damage caused them no lava flow, but a swift current of superheated gas that drags a heavy load of solid matter.
Lateral volcanic explosions are among the most spectacular and devastating natural phenomena, but its dynamics are still poorly understood.
The team of Barry Voight, professor emeritus of geology and geological engineering from Pennsylvania State University, created the 3-D model using the parameters of the explosion of Mount St. Helens, including the equations to determine the mass and thermal energy from the gas along with the size, density and other parameters of the solid particles.
In previous models of the explosion of Mount St. Helens was assumed that was dominated by a supersonic gas jet that originated in the volcanic vent. However, the authors of the new study suggest that besides the initial explosion that hit an area less than 5.8 kilometers from the chimney, the flow of gas and solid particles was driven by gravity. Researchers have concluded that as the distance to the fire grew older, the blast of gas and solid is weakened by the loss of power experienced when encountering obstacles.
Voight’s team has also shown that the spread in all directions of flow of gas and solid matter caused a decrease in flow velocity, and sedimentation particle energy stole the latter.