An experimental study of structures arising in convective roll flows of magma melts in peripheral chambers of volcanoes

Experimental studies on the structure of convection that occurs in a two-layered “peripheral” magma chamber

“…There is one important circum stance that throws new light on the mechanism that maintains the quasi steady state of a volcanic system, especially with a complete absence of external volcanic activity. This is the existence of a continuous interconnec tion, as was experimentally found earlier (Bazarov et al, 2008;Gordeeva et al, 2011), between the peripheral and the mantle magma chamber of a volcano due to a central ascending flow of the melt inside the feeding conduit of the peripheral chamber that goes from the mantle magma chamber (see figure, item 5) and a circular reverse descending flow (see figure, item 22) that goes along the walls of the feeding conduit of the peripheral chamber downward into the region of the mantle chamber. It was found experimentally that the systems of the peripheral and mantle chambers can exist in a quasi steady state for an indefinitely long time owing to the existence of a con tinuous interaction between the counter flows of magma melts in the feeding conduit of the peripheral chamber in the complete absence of any effusions onto the ground surface.…”

“…The pro totypes of the model chambers were the experimental apparatuses that were used in (Bazarov et al, 2008(Bazarov et al, , 2007(Bazarov et al, , 2005(Bazarov et al, , 2002(Bazarov et al, , 2001Gordeeva et al, 2011;Kirdyashkin et al, 1994Kirdyashkin et al, , 2001 with appropriate additional modifications in the inner and outer parts of the model chambers: vary ing thicknesses of the top and bottom of a peripheral chamber, varying dimensions of the "feeding" channel ways, positions of stationary and probing thermocouples and the experimental conditions (varying temperatures of the top and bottom heat exchangers), and so on. The apparatuses make up a system that consists of a transpar ent sealed model crystallization chamber, an optical sys tem for observing the regimes of convective flows and crystallization regime in the model melts of the peripheral and mantle chambers, thermostats that ensure specified thermal regimes in the system, ordinary and slot illumina tors, systems for temperature recording, including high velocity copper-constantan thermocouples with wire diameters between 60 and 200 μm, digital microvoltme ters and nanovoltmeters, etc.…”

“…A detailed description of construction features in crystallization model chambers can be found in (Bazarov et al, 2008;Gordeeva et al, 2011). The continuous recording of temperatures in different parts of model melts in mantle and peripheral chambers and feeding conduits was made by a system of high velocity stationary and probing thermocouples.…”

“…In spite of extensive research that we know of, there are no data on experimental simulation of the dynamics of convective processes and the heat-mass transport mechanisms that are occurring simultaneously in differ ent parts of a volcanic system in the "mantle" and "peripheral" conduits that lead to chambers and volca noes, apart from a few exceptions (Bazarov et al, 2008;Gordeeva et al, 2011).…”