Lava dome

[1] The geochemistry of lava domes can vary from basalt (e.g. Semeru, 1946) to rhyolite (e.g. Chaiten, 2010) although the majority are of intermediate composition (such as Santiaguito, dacite-andesite, present day)[2] The characteristic dome shape is attributed to high viscosity that prevents the lava from flowing very far.

[8] If part of a lava dome collapses and exposes pressurized magma, pyroclastic flows can be produced.

Characteristics of lava dome eruptions include shallow, long-period and hybrid seismicity, which is attributed to excess fluid pressures in the contributing vent chamber.

[11] Gravitational collapse of a lava dome can produce a block and ash flow.

[12] A cryptodome (from the Greek κρυπτός, kryptos, "hidden, secret") is a dome-shaped structure created by accumulation of viscous magma at a shallow depth.

[15] There is another prominent coulée flow on the flank of Llullaillaco volcano, in Argentina,[16] and other examples in the Andes.