A new study published on Naturethe result of the work of Received researchers, New Mexico, Utah and Texas, reveals the mechanism that maintains “under control” the Caldera del Vulcano di Yellowstone, in Wyoming (United States). It is one particularly porous and partially melted layerlocated a 3.8 km deep In the northeastern area of the Caldera, which acts as a “cap” of the magmatic tank and at the same time acts as a relief valve, allowing the release of gases in order to avoid explosive eruptions. Know the mechanisms that regulate the so -called “supervulcan“By Yellowstone is essential, since it is one of the most dangerous in the worldwhich in the past has given rise to violent eruptions.
The discovery of the porous layer under Yellowstone’s caldera
The researchers identified the porous layer by studying the speed of seismic waves In the subsoil of the Caldera, which varies according to the physical and chemical characteristics of the materials crossed. The waves were artificially produced thanks to a 23,800 kg heavy truck, capable of generating small earthquakes. It was thus possible to view the structure below the caldera with a precision never reached before. Past studies had detected the presence of at least seven magmatic tanks containing 400 km3 of Riolithic magmaespecially accumulated in the northeastern area of the Caldera. The presence of a sort of “cap” had also been hypothesized in correspondence with the upper limit of the magma accumulation, but the exact depth was not known and not even the structure.
Because the porous layer under caldera is important
The researchers noticed that a about 3.8 km deep Seismic waves behave very differently than the rest of the magmatic tank. At this depth there is it upper layer of the accumulation of magma, which has been analyzed through computerized models. It was thus noted that this layer of coverage is constituted from porous and partially melted rockcontaining gas bubbles. The presence of many voids in the rock allows gases to gradually escape Making that under the layer the pressure does not increase too much. It is, in practice, a magma cap that acts like a lid by trapping a large amount of heat, but which “breathes” by releasing the gases. On the surface, the manifestation of this mechanism are the intense hydrothermal phenomena, which include Geyser and Fumarole. Decreasing the pressure of the gas, decrease considerably too the probability that an explosive volcanic eruption take place. This does not mean that in the future the volcano will no longer errocar: it is in fact a active volcanowhose last eruption (of effusive type) took place 3300 years ago. However, it is believed that a violent event will occur no earlier than hundreds of thousands of years.
