Mexico - Colima volcano update 6 Feb 2002
A lava dome has filled the crater of Volcán
de Colima, México and provoked the first intermediate-size (up to 1 km
of length) rock falls on the southern flank of the volcano that started
at 17:21 (L.T) on February 4. The lava dome began to grow at the beginning
of May, 2001 (BGVN, 26:05). The velocity of magma ascent sharply increased
in October 2001, and by the end of January 2002, the total volume of the
dome was estimated as 1,450,000 m3. The continuous process of inflation
that was recorded by the deformation monitoring network and the numerous
very small (magnitude less than 0) earthquakes that have been recorded
during the last two weeks indicate a high probability of the formation
of lava and pyroclastic flows that would threaten the residents of the
nearest villages. Based on this information, discussed during the February
4 night meeting of the Scientific Advisory Committee of Colima University,
the authorities of Colima State decided to evacuate the nearest village
of La Yerbabuena, situated at a distance of 8 km from the crater. The evacuation
of about 200 persons from took place on February 5. ( Universidad de Colima))
As of the 3rd of February, Universidad
de Colima has reported that an aerial observation was attempted on 2 Feb
at Colima but was thwarted by weather conditions. However, brief periods
of incandescence from the new dome continue to be observed. The monitored
parameters do not show significant changes in last the 24 hours. They continue
being observed incandescence of short duration in the top. In the flights
made on Feb. 2 by Members of the Advisory Scientific Committee, the state
could not be appreciated in which is the dome due to the climatologic conditions.
The colour code at Colima is currently at YELLOW. The recent activity of
the volcano of Colima on is declared by the growth of a dome (it stains
black) in the top, that has been visible from the city of Colima on for
several days. Nevertheless this phenomenon gave beginning in the month
of October of 2001 and has been monitored from its origin by the Advisory
Scientific Committee for the Volcano of Colima on. The Advisory Scientific
Committee has raised the possibility of occurrence of two scenes with base
in the pursuit of the monitoring parameters, as well as in the observation
of the type of eruptive activity during last the forty years: 1) first
of them it is that in the course of days to weeks the dome collapse or
spills by the South flank, generating a lava front accompanied by the well-known
hot flows of ash and rock (pyroclastic flows), similars to observed in
November and the December of 1998. Probably the reach of the initial flows
will be similar to those of that year, that is to say, will reach smaller
distances to the 5 kilometers. The movement of these flows will generate
ash clouds that could hurry on the neighboring populations, depending on
predominant winds. In this respect it will be necessary to take into account
that the ash precipitation on the water bodies could cause its contamination
reason why it is recommended to maintain places setting: sinks, drainages
and wells. 2) the second scene is that this dome lets grow and that in
an indetermine time they happen one or several explosions like those of
February, May and July of 1999, destroying parts or the totality of the
dome, whose reach of sent fragments (ballistic missiles) will not exceed
a radius of 5 kilometers from the top. The possibility that does not discard
both phenomenons appear permanent in the time. Information translate from
spanish : University of Colima - Advisory scientfic Committe.