Lava domes are rounded, steep-sided mounds built by magma that is highly resistant to flow, usually either dacite or rhyolite. Such magmas are typically too viscous to move far from the vent ...

The summit is truncated by a broad 9km-wide caldera breached to the south, with numerous lava domes on the outer flanks. The lava dome complex was built within the large open caldera. Regular ...