ERUPTION OF SHIVELUCH VOLCANO IN 2001-2004, KAMCHATKA
S.A. Fedotov., N.A. Zharinov., V.N. Dvigalo., N.I. Seliverstov., S.A. Khubunaya.
Institute of Volcanology and Seismology FED RAS, Petropavlovsk-Kamchatsky, 683006, Russia
Sheveluch is the northernmost and most dangerous andesitic volcano of Kamchatka. In
the last 65,000 years it has been the second-most productive volcanoes of Kamchatka with an
average eruption rate of magma 36 million tons per year. It is also one of the biggest Kamchatka
volcanoes; the diameter of its base is about 45-50 km, its altitude is 3283 m and its volume is about
1000 cubic km. The last paroxysmal explosive eruptions of Sheveluch happened in 1856 and 1964.
The explosive crater formed in 1964 has an approximate size of 1,5x3 km and is active now. A
new extrusive dome is growing in the crater of Shiveluch, which began growing after the
catastrophic explosive eruption in 1964. We identify 3 stages of the dome growth.
In August of 1980, an extrusion began and lasted till the end of 1981. The next stage
lasted from April 1993 till January 1995. During the second stage, the dome reached a height of
350 m, its base was 1000x1700m across and its volume amounted to 0.18 cubic km. The last and
3-rd stage began in the end of April 2001 and continues at present. Two first inter-paroxysmal
stages were mainly extrusive.
The last eruption of Shiveluch started on April 30, 2001 (extrusive phase). It was
preceded and accompanied by volcanic earthquakes of a magnitude M≤3 and volcanic tremor.
The number of earthquakes below Shiveluch increased abruptly (up to 150-200 per day) from
April 23 to April 25. Up to 380 earthquakes were recorded per day from the end of April to
beginning of May 2001. Five to 30 of these earthquakes had «the energy class» magnitude of 6
and higher.
The volume and the height of the lava dome at Shiveluch volcano during
1944-1948, 1980-1981, 1993-1995, 2001-2004.
V(млн.
─ - height of the dome, m.
м3)
06.06.01
06.10.01
06.02.02
06.06.02
06.10.02
06.02.03
06.06.03
06.10.03
06.02.04
06.06.04
04.04.93
04.08.93
04.12.93
04.04.94
04.08.94
04.12.94
04.04.95
15.01.82
15.09.81
15.05.81
15.01.81
550
500
450
400
350
300
250
200
150
100
50
0
15.09.80
01.08.44
01.12.44
01.04.45
01.08.45
01.12.45
01.04.46
01.08.46
01.12.46
01.04.47
01.08.47
01.12.47
01.04.48
01.08.48
Н(м)
550
500
450
400
350
300
250
200
150
100
50
0
──
3
------ - volume of products of the eruption, mln. m .
An official short-term forecast for this eruption was submitted on April 23, 2001 on the
basis of a report by V. Ivanov. On May 12, 2001, V. Dvigalo observed from Klyuchy settlement
a new extrusive dome on the western slope of the old dome. A maximum rate of the dome
growth – a discharge rate of the eruptive products of 0.6 million m3 per day – was noted at the
beginning of the eruption. The extrusive process was interrupted by explosive phases of the
eruption.
The main explosive phase of the eruption continued from May 19 till May 22, 2001 when
volcanic tremor returned to background and local seismicity diminished. On May 19 the absolute
height of the eruptive column was up to 20 km, its length reached to 500 km. The length of
pyroclastic flows amounted to 18 km at a thickness of 8 m.
Deposits of pyroclastic flows were mainly juvenile round clasts of pumiceous amphiboleplagioclase andesites, volcanic bombs and resurgent fragments and blocks of the lava dome (3-5
mm in size), immersed into ash and sand pyroclastic matrix of andesite composition (SiO 2 62.663.2 wt %). Two months after the eruption the temperature at a depth of 1 meter in the pyroclastic
flows was about 120 degrees C. Lahars covered the area of about 70 square km and reached up to
30 km from the volcano. The thickness of lahars was 10 m.
The present stage of Sheveluch volcano has some distinctive features:
1. The eruption of 2001-2004 of Sheveluch differs in its high levels of seismicity. There is a
tendency of regular growth of seismic events connected with inter-paroxysmal eruptions of
Sheveluch as its crater is filled with extrusion. The eruption of 1980-1981 was neither
preceded nor accompanied by any noticeable seismicity. Before and during the eruption of
1993-1995 a number of earthquakes under the volcano reached to 250-300 per day; their
“energy class” magnitude reached Ks=7.0, while the period of the relatively high seismic
activity lasted about two weeks. The eruption of 2001 was preceded by a burst of seismic
activity which lasted no less than 6 weeks and was accompanied by a high level of seismicity:
a number of seismic events reached 300-400 per day; the highest «energy class» magnitude
was 9.5. Before the catastrophic eruption in 1964 when the volcano crater was almost
completely filled with extrusive lava, earthquakes of «the energy class» magnitude Ks=12
were registered.
2. The growth of the lava dome in the crater of the volcano occurs irregularly. After the
paroxysmal eruption of 1964, we identify three stages of dome growth distinguished in volume
and composition of eruptive products. During the last three eruptions, SiO2 is increasing very
slowly. The content of SiO2 during the eruptions of 1980-1981, 1993-1995 and 2001-2004 are
respectively close to: 60.4-61.3, 61.8-62.7, 62.6-63.2.
3. The character of the last three eruptions changed from purely extrusive in 1980-1981 to
extrusive-explosive in 1993-1995 and 2001-2004. During the first eruption of 1993-1995, there
was extrusion of viscous, degassed lava. While the next two subsequent eruptions, growth of
the lava dome was accompanied by numerous explosions. This suggests the arrival of gasenriched andesitic magma.
4. Now, the volume of the inter-crater lava dome has reached the volume of Suelich dome, which
was formed during 1944-1950 before the eruption of 1964. The volume of the modern dome is
close to 0.30x106 m3 with a basal diameter of t 1350 m. The height of the current dome first
measured from the surface in 1980 is 520 m.
5. During 1980-2000, the eruption rate was close to an average of 36 million t per year. At the
same time, since 1964, two times more magma could have been accumulated in the feeding
chamber. Therefore, in the upcoming decades we can expect inter-paroxysmal eruptions with a
volume of 0,1 - 0,15 km3 of erupted materials. Obviously, an increase in the volume of the
extrusive dome could be possible, as well as a growth of new extrusive domes.