Avachinsky volcano: eruption updates
Avachinsky volcano (Kamchatka): deep earthquake swarm
Friday Aug 02, 2013 05:58 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:
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.
Links / Sources:
Links / Sources:
- Avachinsky : crise sismique profonde (Blog Culture Volcan)
Monday, May 19, 2008
Avachinsky volcano is getting active, producing ash eruptions. An ash plume was observed rising to an altitude of 4.3 km (14,000ft) a.s.l. on 10 May. ... [more]