A large-scale geophysical campaign to study the giant volcanoes of Kamchatka in Russia
On the Kamchatka peninsula in Russia's far east, the Kluchevskoy volcano group is part of the Kuril-Kamchatka volcanic chain. This volcanic formation is the result of subduction of the Pacific plate beneath the Kamchatka peninsula.
The very vigorous and varied volcanism of the volcanoes in this group (KVG for Kluchevskoy volcanic group), located under an international flight corridor between North America and Asia, makes it a natural laboratory for studying large volcano-magmatic systems.
Previous studies have shown that over the last 7,000 years, the Klyuchevskoy volcano alone has produced an average of 1 m3 of erupted rock per second. This very high eruption rate, higher than most subduction volcanoes, is comparable to that of the volcanoes of Hawaii (often considered the world’s most active volcanic system).
The 12 other stratovolcanoes in the KVG group, including Tolbachik and Bezymianny, have also been very active in recent decades; and two other equally active volcanoes, Shiveluch and Kizimen, lie just to the north and south of the Klyuchevskoy group.
But the eruptive style of the volcanoes in this region is highly varied: for example, the most recent eruptions at Tolbachik were Hawaiian in style, while Bezymianny produced large explosive eruptions such as that of 1956.
The origin of this very vigorous volcanism is a priori linked to the region’s particular tectonic context: the proximity of the Kamchtka-Aleutian subduction wedge and the subduction of the Hawaii-Emperor submarine mountain range (see figure 1).
To better understand the mechanisms governing this large volcano-magmatic system and the possible scenarios for its future evolution, it is important to know the deep structure of the crust and upper mantle in a sufficiently wide region around the volcanic group.
Previous studies using geophysical imaging methods have suffered from a lack of depth resolution due to poor instrumental coverage, and have failed to provide a global representation of the deep structure beneath the Klyuchevskoy volcano group.
To improve our knowledge of this deep structure, an international team (comprising researchers from the Institut de Physique du Globe in Paris, the Institute of Volcanology and Seismology of the Russian Academy of Sciences, the Geophysical Service of the Russian Academy of Sciences, the Institute of Petroleum Geology and Geophysics of the Russian Academy of Sciences, and the Helmholtz Center in Potsdam, Germany (GFZ)) conducted a large-scale seismological campaign in this region. The experiment was named KISS: Klyuchevskoy Investigation-Seismic Structure of an Extraordinary Volcanic System. Over 80 temporary seismological stations were installed during the summer of 2015. These stations were set up in sparsely populated regions, in sometimes difficult conditions, and most of the instrumentation sites were accessed using 4×4 trucks or hitchhikers.
During the summer of 2016, 77 stations (those not damaged by either environmental conditions or bears) were recovered. With the addition of the network of permanent stations, data from around a hundred stations is now available.
Over a period of 1 year, this network recorded numerous earthquakes of tectonic and volcanic origin, including those associated with the Klyuchevskoy eruption that began in April 2016. The article describing this geophysical campaign has recently been published in the journal EOS, and the scientific team is completing the preparation of the database (the data will be publicly available after the 3-year restriction period) and starting their analysis, the first results of which are expected towards the end of 2017.
Ref : Shapiro N, Sens-Schönfelder C, Lühr B, Weber M, Abkadyrov I, Gordeev E, Koulakov I, Jakovlev A, Kugaenko Y, Saltykov V. 2017. Understanding Kamchatka’s Extraordinary Volcano Cluster. Eos DOI: 10.1029/2017eo071351
