Eruption column

The volcanic materials form a vertical column or plume that may rise many kilometers into the air above the vent of the volcano.

Intrinsic factors include the diameter of the erupting vent, the gas content of the magma, and the velocity at which it is ejected.

Extrinsic factors can be important, with winds sometimes limiting the height of the column, and the local thermal temperature gradient also playing a role.

The atmospheric temperature in the troposphere normally decreases by about 6-7 K/km, but small changes in this gradient can have a large effect on the final column height.

Ashes and aerosols in the troposphere are quickly removed by precipitation, but material injected into the stratosphere is much more slowly dispersed, in the absence of weather systems.

In two separate incidents in 1982, airliners flew into the upper reaches of an eruption column blasted off by Mount Galunggung, and the ash severely damaged both aircraft.

Similar damage to aircraft occurred due to an eruption column over Redoubt volcano in Alaska in 1989.

Satellite animation of the initial eruption column and shockwave from Hunga Tonga–Hunga Haʻapai on 15 January 2022
Eruption column over Mount Pinatubo in the Philippines , 1991
Eruption column rising over Redoubt Volcano , Alaska, on 21 April 1990, which reached a height of about 9 km (5.6 mi) [ 2 ]
The eruption column produced by the 1980 eruption of Mount St. Helens as seen from the village of Toledo, Washington , which is 56 km (35 mi) away. The cloud was roughly 64 km (40 mi) wide and 24 km; 79,000 ft (15 mi) high.