VOLCANISM Strombolian activity in Bromo Crater Strombolian eruptions are relatively low-level volcanic eruptions, named after the Sicilian volcano Stromboli, where such eruptions consist of 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. They are defined as ...Mildly explosive at discrete but fairly regular intervals of seconds to minutes... The tephra (tephra- Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size or emplacement mechanism) typically glows red when leaving the vent, but its surface cools and assumes a dark to black color and may significantly solidify 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. Strombolian eruptive activity can be very long-lasting because the conduit system is not strongly affected by the eruptive activity, so that the eruptive system can repeatedly reset itself. For example, the Parícutin volcano erupted continuously between 1943-1952, Mount Erebus, Antarctica has produced Strombolian eruptions for at least many decades, and Stromboli itself has been producing Strombolian eruptions for several thousand years. Mount Bromo (2392m) is a small pyroclastic cone which rises 133m above the surrounding floor of the massive (9x10km) Tengger Caldera. This caldera, also referred to as the sand-sea caldera due to its flat sandy floor, is the result of the collapse of the top half of a probably nearly 4500m high pre-caldera stratovolcano over 250000 years ago. Bromo has been frequently active since historical records began in 1804, with a total of over 50 eruptions being recorded up to the present date. Due to its location on the base of a steep-walled caldera, it generally only poses a local threat to life during explosive eruptions. These may occur with little warning. Such an eruption occurred on 08.06.2004 and accounted for 2 fatalities in the vicinity of the crater due to the impact of ballistics. Damage to vegetation may occur over a much wider radius, as could be witnessed during e.g. the 2010-2011 eruptive phase. Read more about Strombolian Eruption: geology.sdsu.edu/how_volcanoes_work/Strombolian.html
Posted on: Sat, 10 May 2014 16:12:12 +0000
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