When you have seen a land formation which is in the shape of
a rough circular mound-shaped protrusion resulting from the slow extrusion of
viscous lava from a volcano, then most probably what you are seeing is a lava
dome or a volcanic dome. Some of these lava domes’ geochemistry vary from
basalt to rhyolite. Although the usual content are those mentioned, most of the
preserved domes tend to have high silica content. The sleep flanks can
partially destroy the domes. These can result to the collapsing and breaking
into a jumble of blocks and ash that flow downhill. These domes can also be
destroyed due to the explosions inside them. This happens when trapped gas
builds up so much inside that it can no longer be held.
