Mt. Erebus contains an active tephriphonolitic lava lake in its summit crater. Since the mid 1970's, the general size and shape of the lava lake has been noted by researchers. Each year, after 10 months of no observations, scientists return to Mt. Erebus to find the size and shape of the lava lake different from the previous year. As no one is present during the austral winter to observe slow or catastrophic changes to the summit crater, it is difficult to ascertain how and why the lava lake is being modified. With the addition of a video camera system that peers into the summit crater, it is hoped year round observations will now be possible. To look at some of the video footage of the previous field season, please check out the Mt. Erebus Volcano Observatory Multimedia site.

Image above is the summit crater of Mt. Erebus, looking to the northeast. The lava lake is approximately 100 meters below the crater rim in the north side of the crater.

The Mt. Erebus lava lake, as photographed circa 1984. Note the prominent levee structure surrounding the molten lava. The lava lake diameter varies from year to year; here is approximately 40 meters across, which was the largest for the past several decades.

The Mt. Erebus lava lake, as photographed in December of 2000. Only a small amount of molten lava (red) can be seen where the volcanic gas is venting. However, in this image we can see that the floor of the crater is covered with fresh volcanic bombs.

The interior of a volcanic bomb from Mt. Erebus shortly after it was erupted from the lava lake. The bombs erupted from Mt. Erebus expand quickly because of the gases dissolved in the magma and thus are relatively light and frothy. This bomb fragment is small (note the size 12 boot in the background), but some bombs erupted from the lava lake are the size of automobiles.