Earth Watch Report - Volcanic Activity
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Wikipedia
Jan van der Crabben (Photographer)
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| Description |
| A
(so far small) seismic crisis has started about a week ago. The
earthquake hypocenters are currently located at depths around 30 km SE
of the volcano. The new quakes superimpose to the normal seismic
activity at shallow depth. It is not clear whether this indicates that
magma has started to accumulate at the mantle-crust boundary beneath the
volcano, or whether the seismic activity there is purely tectonic and
related to the subduction of the Pacific Plate. Currently, there are no
indications that the volcano might be in for a new eruption, but since
Avachinsky is located very close to Kamchatka's capital town of
Petropavlovsk with 200,000 inhabitants, it is being monitored closely by
Russian scientists. As Blog Culture Volcan who posted about this story
first pointed out, recent studies on the magma plumbing system of
Avachinsky show that the volcano's recent eruptions, at least the one in
1991, were fueled by at least two different shallow magma chambers:
These are located at 1.8 and 5.5 km depth beneath the summit, and
correspond to the boundaries between the floor of the caldera (formed
about 30,000 years ago) and the present summit cone, and the contact of
the volcanic edifice as a whole overlying carbonate sediment basement,
respectively. In both cases, the geologic contact between of different
rock types with different densities and structures seem to stop dike
propagation and act as storage regions for magma. On the other hand, no
deeper magma reservoir has been identified for Avachinsky, and no
progression of epicenter depths towards the surface has been seen for
the recent deep quakes. This favors the interpretation that the observed
quakes are mainly tectonic in origin. |
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Avachinsky volcano (Kamchatka): deep earthquake swarm
Friday Aug 02, 2013 07:58 AM | BY: T
Location of recent quakes under Avachinsky (blue dots) (EMSD)
A
(so far small) seismic crisis has started about a week ago. The
earthquake hypocenters are currently located at depths around 30 km SE
of the volcano.
The new quakes superimpose to the normal seismic
activity at shallow depth. It is not clear whether this indicates that
magma has started to accumulate at the mantle-crust boundary beneath the
volcano, or whether the seismic activity there is purely tectonic and
related to the subduction of the Pacific Plate.
Currently, there are
no indications that the volcano might be in for a new eruption, but
since Avachinsky is located very close to Kamchatka's capital town of
Petropavlovsk with 200,000 inhabitants, it is being monitored closely by
Russian scientists.
As Blog Culture Volcan who posted about this
story first pointed out, recent studies on the magma plumbing system of
Avachinsky show that the volcano's recent eruptions, at least the one in
1991, were fueled by at least two different shallow magma chambers:
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