Mt. Erebus has historically erupted in three distinct modes: strombolian, phreatic and effusive. The most common form of Mt. Erebus eruption is the strombolian explosion. In general terms, large gas pockets from deep in the Mt. Erebus magma chamber rise to the near surface of the persistently convecting lava lake where they explosively decompress, ejecting molten material (bombs) beyond the confines of the lava lake. The size of the strombolian eruptions can vary from small bubbles on the surface of the lava lake to large explosions that virtually empty the lake and throw large bombs hundreds of meters into the air. In the past year, seismic instruments have recorded dozens of strombolian eruptions each day. When the crater is free from bad weather and volcanic gases, the video system is able to record high quality movies (some with audio) of these eruptions. Visit our Strombolian Eruptions page to view some of these spectacular events.
A far less common type of eruption is the phreatic (aka "ash") eruption. Phreatic eruptions on Mt. Erebus occur when snow and ice interact with hot rock/lava producing rapidly expanding steam which is capable of pulverizing rock. The pulverized rock (ash) billows from vents located on the crater walls. These ash eruptions were most prevalent during 2000 and 2001. Some of the larger Phreatic Eruptions have been captured by the video system.
Although the vast majority of the volume of Mt. Erebus consists of lava flows (as opposed to pyroclastic material), all of the historic activity of the volcano has been confined to the summit crater. However, during January of 2001, a very small lava flow was observed being emitted by one of the crater vents. Because the flow was erupted over a period of several hours, the Lava Flow movie is actually a time-lapse compilation of still images.
Additional movies have been added for your viewing enjoyment. Many of these movies will hopefully give a sense of the scale of the Mt. Erebus environment that still photographs may not.