Yellowstone volcano SHOCK: Magma chamber scans REVEAL 'network’ of magma under Yellowstone

's magma chamber likely resembles an intricate network of magma-filled tubes and tunnels deep beneath the ground. Until recently, geologists studying supervolcano eruptions assumed the magma chamber resembled a vast cavern in the Earth’s crust filled with molten rock. But the traditional magma chamber model was challenged this week by new geophysical imaging of supervolcano systems. The USGS, which is responsible for Yellowstone volcano monitoring, said the study will have an impact on how future Yellowstone eruptions are predicted.

The USGS said in its weekly edition of the Caldera Chronicles: “What does a magma chamber look like? At first thought, many of us would imagine a large cavern in the crust filled with molten rock.

“While this has been the traditional model for a number of decades, geophysical imaging of the regions below volcanic systems have never found evidence for this style of magma storage.

“As more data become available from geochemical and geophysical studies, our idea of what a magma chamber looks like has continued to evolve.

“By understanding what a magma system looks like prior to an eruption, we can start to understand how volcanic reservoirs are built and sustained over time.”


The information can help geologists better “monitor and prepare” for eruptions.

Supervolcano studies suggest volcanic magma is stored at a depth of many miles in a so-called “mush zone”.

This mush zone is a large and semi-rigid region formed between 50 percent to 70 percent from crystals as well as small amounts of molten rock.

Under the new magma chamber model, these pockets of melt are distributed beneath a volcano and can be connected to one another or completely isolated.


These pockets of molten rock will likely merge over decades or entire centuries leading up to a major eruption.

And during a blast, the pockets are “tapped sequentially” as the molten rock makes its way to the surface.

The USGS said: “In other cases, melt bodies may not fully merge at depth, and instead could be erupted from multiple vents.

“This might explain why large bodies of melt have never been imaged, even though large eruptions have obviously occurred at places like Yellowstone.


“This knowledge has important implications for how we monitor volcanic systems, especially when interpreting geophysical data, since it redefines what we might consider an active or eruptible magma reservoir.”

In the case of Yellowstone , geologists have found the Huckleberry Ridge eruption—the biggest of Yellowstone's three major blasts – came from four separate melt pockets.

The eruption, which went off about 2.1 million years ago, spewed about 600 cubic miles (2,500 cubic kilometres) of volcanic material.

Thankfully, recent studies of Yellowstone volcano’s magma reservoirs do not reveal any evidence of substantial melt pockets beneath the supervolcano.

The USGS said: “In fact, geophysical imaging shows that the mush zone consists of only about five to 15 percent melt, which indicates that a large eruption is not likely to happen anytime soon.”

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