V.I. Andreev, G.A. Karpov, M.A. Maguskin, V.M. Miroshnikov
The
Institute of Volcanology, Far East Division, Russian Academy of
Sciences, 683006,
Petropavlovsk-Kamchatsky, Piip blvd., 9, Russia
Submarine eruption
in the Akademii Nauk Caldera, having continued for about one day,
was accompanied by seismic activity and creeps that went on for
several years. Two powerful lachars, one accompanying the eruption,
the other having emerged four months later, brought to the Karymaskaya
river valley about 106 m3 of fine, mostly volcanic material, a considerable
portion of which deposited at the broadest and flattest areas of
the valley. Redistribution of the ash having settled onto the ground
surface, lasted several years and led in some cases to a significant
contrast of the ash thickness at neighboring areas. Moderate ash-falls,
which had happened here for hundreds of years before, supported
local formation of relatively thick soil-ash beds. Because of the
earth surface deformation, contrast zones got distinguished, where
geothermal manifestations livened up or faded. Loose volcanogenic
material in the vicinity of the Karymsky volcano underwent compression
that was the most notable in sites where there were fewer large
monolithic fragments. The masses of lithified volcanogenic-sedimentary
deposits in the southern sector of the Karymsky volcano caldera
as well as those of geyserite deposits around the Akademii Nauk
springs, whose thickness was about 1 m, screened and localized thermal
spring discharges.
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