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Santiaguito was borned during the 1902-eruption of Santa
Maria. There have been continuously eruptions
since 1922,
and scientists range Santiaguito as one of the 10 most dangerous
volcanoes on the earth to day.
As
lavaflows, ash, debris and pyroclastic flows are numerous, Santiaguito
changes shape continuously.
In most recent time those pyroclastic
flows have reached the nearby rivers, which in turn results
in lahar and mudflows.
The cityh of El Palmar is only 10 km away, and has twice been damaged
by lahar from Santiaguito.
Thursday, January 12th, 2012
INSIVUMEH reported that on 6 and 10 January explosions Santa María's
Santiaguito lava-dome complex generated
ash plumes that rose 600 m above the complex and drifted N and W, respectively.
Crater incandescence was observed
at night and active lava flows
on the SE and SW flanks generated block avalanches. Based on analyses
of satellite imagery,
the Washington VAAC
reported that an ash plume drifted 18.5 km E of the Mexico border.
February
19th, 2003
As of the 18th of February, the Wshington VAAC as well as colleague
Dan Shackelford reported that the Santiaguito
dome on the flank of Guatemala's Santa Maria volcano was erupting explosively
on the evening of 16 February, continuing
into the 17th, producing ash clouds to 3 km a.sl. (300 - 600m above
the dome) explosions overnight and this morning.
The VAAC reported that at 10,000ft., a 3 nm wide line of ash extending
between N14.45 W091.33 to N4.35 W091.38.
Ash is moving S at 10 knots. An ash plume is seen in GOES-8 visible
imagery. INSIVUMEH reports explosions with
ash extending 300 to 600 m above the summit. The explosions are coming
from the Santiaquito volcano which is at a
lower elevation than the summit of Santa Maria.
Photograph
copyrighted and provided by Steve O'Meara of Volcano Watch International.
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The
last periode of heavy eruptions (1972-1975) was marked by several large
lvaflows, accompanied by large block and clouds of ash. During those
frequent eruptions, two new vents developed. Since 1977 it is however,
only the Caliente-vent, the main crater on Santiaguito, that has been
active. From 1975 to 1984 pyroclastic eruptions dominated the activity.
As per now the prominent threat is lahar-mudflows, which developes when
the monsun-season starts each year,
and those flows covers an area more than 10 kilometers from the volcano.
This problem got worse in the middle
of 1970's, when the eruptions moved to the easter side of the dome,
from where the way down the valleys and
rivers below was open - and which now has been inhabited once more during
the past 40 years.
If the next eruptional period comes from this vent, the risk will increase
dramatically. The big eruptions in 1929-1933
resulted in large blocks
and lahar, and many
people were killed.
New
eruption from
Caliente-crater on the 19th of July, 1989..
The flow moved 4 kilometers down the Rio Nima II-valley..
This picture was taken from a place 10 kilometers away..
Photo by: F.Michael Conway (MTU)
That eruption in 1929, which was damaging to the volcano
itself, sent a mixture of pyroclastic ash and blocks down more than
10 kilometers south of Santiaguito. The devastation resulted in hundreds
of dead people, and violent damages of villages and plantations. Similar
flows has developed since 1930, but not so violent, and the damages
minor.
It was on November 2nd, 1929 that a pyroclastic flow
moved down an almost vertical ridge, 1.800 m down the valleys to the
rivers Nimá II and Tambor, and laid an area of 15 quadratkilometers
devasted, and killed may be as many as 5.000 people. Ash felt during
9 hours in Retalhuleu 27 kilometes away.
El
Brujo -dome, part of Santiaguito
Photo by Bill Rose, February
1970.
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