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Phreatic - explosion
driven by steam produced by heating and expansion of groundwater
due to an underlying hot source.
This type involves only water, steam and ash with other
rock fragments derived from pre-existing rocks, without ejection
of fresh magmatic materials.
Examples:
1993 & 1996 eruptions of
Canlaon Volcano
1988 eruption of Bulusan
Volcano
Phreatomagmatic - eruption resulting from the
ejection of magmatic gases and steam produced by the conversion
of groundwater to steam by ascending magma, mixed with water,
fine ash with or without accretionary lapilli and variably-sized
volcanic bombs fragmented from the pre-existing rock formations,
and fresh magmatic ejecta.
The eruption forms a high eruption column with a radially
spreading ring-shaped horizontal cloud at the base due to
peeling of the crater lip or deflection in the rise of later
ejections caused by the pressure of falling pyroclastic
materials.
Example:
1965
& 1967 eruptions of Taal Volcano
Strombolian - weak
to violent eruption characterized by lava fountaining and
effusion of molten lava. Typical
ejecta are ovoid and fusiform bombs and scoria (cinders).
Ash is relatively minor in amount and eruption cloud is
generally yellowish to white in color.
Examples:
1968 & 1969 eruptions of
Taal Volcano
1978 eruption of Mayon Volcano
First phase of 2001 eruption
of Mayon Volcano
Vulcanian - eruption
resulting from the release of large quantities of accumulated
magmatic gas which lefts fine ashes and blocks coming from the
magma with great force high in the air forming voluminous
eruption clouds.
Examples:
First phase of 1993 eruption of
Mayon Volcano
2nd phase of 2000
& 2001 eruptions of Mayon Volcano
Peleean - eruption
caused by the release of large quantities of gas from an
extremely viscous magma that hurls out ash and other pyroclastic
materials and is characterized by the presence of nuee ardente
or glowing avalanche consisting of hot gases made dense by a
suspended load of pyroclastic material.
Example:
1948-1953
eruption of Hibok-Hibok Volcano
Plinian - eruption of great violence
characterized by voluminous explosive ejections of pumice and
pyroclastic flows. The copious extrusion of gas-rich silicious
magma is commonly accompanied by collapse of the top of the
volcanic cone forming a caldera. Example: Pinatubo Volcano 1991
eruption.
Example:
1991 eruption of Pinatubo Volcano
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