Strombolian eruption

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A Strombolian eruption

Strombolian eruptions are relatively low-level volcanic eruptions, named after the Italian volcano named Stromboli, where such eruptions consist of rhythmical ejection of incandescent cinder, lapilli and lava bombs to altitudes of tens to hundreds of meters. They are small to medium in volume, with sporadic violence.

The tephra typically glows red when leaving the vent, but its surface cools and assumes a dark to black color and nearly soilidifies before impact. The tephra accumulates in the vicinity of the vent, forming a cinder cone. Cinder is the most common product, the amount of volcanic ash is typically rather minor.

The lava flows are more viscous, and therefore shorter and thicker, than the corresponding Hawaiian eruptions; it may or may not be accompanied by production of pyroclastic rock.

Instead the gas coaleses into bubbles, that grow large enough to rise through the magma column, bursting near the top due to the decrease in pressure and throwing magma into the air. Each episode is caused by the release of volcanic gases, typically a few minutes apart, sometimes rhythmically and sometimes irregularly.

Strombolian eruptions are long-lasting, from few hours to days to several years; eg. the Parícutin volcano erupted continuously between 1943-1952. The Izalco volcano has also grown by Strombolian eruptions.