Scientists are closing in on the origin of Mount St Helens as the volcano has been raising questions as to its location and alimentation source.
Although a number of 35 years have passed since its last major eruption, Mount St Helens still is one of the most active volcanoes pertaining to the Cascade arc.
As part of the North-South chain of Pacific Northwest volcanoes, the group was noted to have formed above the Juan the Fuca subducting tectonic plate.
Ever since its last major eruption, scientists have been actively researching the area and the volcano’s history as it has a most unusual location which places it farther away from the main volcanism arc.
Mount St Helen was categorized as a stratovolcano, or a composite volcano thanks to its symmetrical cones. These are steep-sided and built on a number of alternating, diverse layers of ash, volcanic flows, and other such debris.
Stratovolcanoes are considered to be quite dangerous as they erupt in a more explosive manner than most other and can pose quite a threat to the humans and properties nearby.
The location of Mount St Helens, which is situated almost 30 miles west of the course of arc volcanism and Mount Adams, has been a cause of mystery as researchers could not detect its magma source.
Previous research failed to offer answers as to the deep magnetic structure and plumbing system of the volcano, nor of its link with the Cascadia subduction arc.
In a new study released Wednesday in the Nature Communications, a team of researchers set out to explain the architecture of the magmatic subsystem which fuels Mount St Helens.
The team of researchers is part of the iMUSH collaboration or the Imaging Magma Under St. Helens and has been using a number of 900 autonomous seismographs, arranged around a 15 kilometers radius of the summit’s crater.
After all the seismographs were set in place, the team detonated 23 active source explosions which resembled small earthquakes, 2.0 degrees in magnitude. The explosions were captured by almost 4,800 individual cameras.
The resulting data offered scientists the chance to analyze the high-resolution seismic imagining obtained through the explosions of the volcano’s deep crustal structure.
As all the geophysical data involved in the iMUSH project has been gathered, initial analyses seem to point out that the activity of Mount St Helens could be influenced by the thermal structure of the mantle wedge.
With the thermal structure of the volcano being thought to have influenced the volcanic activity of the mountain, it also raises new questions. The cold mantle should not be able to produce the elevated temperatures which allow for the arc derived magmatism.
Whilst researchers now face a thermal paradox, initial data also seems to suggest that the magma supply which fuels Mount St Helens is located somewhere in the eastern area of the volcano.
As this would place it in the mantle wedge under Mount Adams, the magma is thought to reach St Helens by traveling through the magmatic system in a way as yet undiscovered.
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