Eruptions

Volcanoes erupt differently depending on the composition of the magma beneath the surface, the amount of gas in the magma, and the type of vent from which it erupts. In general, the more viscous, or stiffer, the lava, the more explosive the eruptive activity. During explosive eruptions, the lava erupted is torn into shreds, forming a variety of fragmental or pyroclastic materials depending on the physical state of the lava and on the force of the explosions. Explosive eruptions can eject a large amount of material into the air. Nonexplosive eruptions produce lava flows and eject very little pyroclastic material into the air.