Types of volcanic eruption. Artwork showing four different types of volcanic eruption: Surtseyan (upper left), Hawaiian (upper right), Strombolian (lower right) and ultra-Plinian (lower left). A Surtseyan (or phreato-magmatic) eruption occurs when viscous magma comes into contact with water (here the sea). A Hawaiian eruption produces fluid and extensive lava flows, rather than explosive ash falls. Strombolian eruptions are regular, small, explosive eruptions of lava and ash. An ultra-Plinian eruption is the largest type of Plinian eruption, forming an ash column that can be over 25 kilometres high, spreading out to form mushroom-shaped clouds in the stratosphere and depositing ash over a large area.