The depth of this boundary varies with time, being driven by the rate at which the gas escapes the WMS to feed the persistent gas plume at the summit craters, leaving the CMP, which accumulates within the shallow plumbing system, until erupted.
The overpressure of the gas phase in the WMS, acting like a piston cylinder, is fundamental in driving the eruption.
It is a different story when the same rubidium-strontium method is used to date lava from volcanoes on the north rim of the Grand Canyon.
We know these volcanoes are some of the youngest rocks in the canyon, because they spilled lava into the canyon after it had been eroded.
Ferlito also points out a problem with another theory that suggests steam and gases might be released from magma inside the volcano before it can be expelled, causing the magma to fall back into the volcano.
He notes that if this were the case, the volcano would inflate like a balloon.
Unique volcanic structures, known in the literature as “lava trees” and “tree molds”, have formed at several sites on Mt. They form when a fluid lava flow runs over a tree, wraps around it and, while the wood burns off, solidifies forming a hollow cast of the tree.
The inhabitants of the Etna area call these formations “pietre cannone” (“cannon stones”) because of their cylindrical shape.
The results are surprising: the moles H2O/mol basalt ratio is 1.41, which means that Mount Etna erupts 10 times the maximum H2O that could be dissolved in magma and 40% more moles of gas (H2O, CO2 and S) than moles of basalt.Etna behaves more like a giant hot spring than a volcano.He is not, as some publications have suggested, claiming to have found evidence showing that Mt.Negative fluctuations in the gas flux would decrease the heat supply, promote viscosity and trigger eruptions.Moreover, this view of the volcanic system, subverting the common paradigm in which the gas emitted is associated with an equivalent amount of degassing magma, explains the phenomenon, known as the 'excess degassing problem', which affects volcanoes of basaltic and andesitic nature worldwide.