Mauna Kea reigns over the island of Hawaii and seems to be incapable of making peace with the lack of activity that comes with retirement.
The 4,207.3 meters above the sea level volcano is in its post-shield stage, as it should be after one million years of existence. In volcanic language post-shield means retirement.
Its constant mumbling seems to say that becoming dormant doesn’t suit the tallest mountain in the world. That’s natural since Mauna Kea is also one of the youngest mountains from the Hawaiian–Emperor seamount chain.
From 1999 to 2018, more than a million deep long-period earthquakes (DLP) were caused by Mauna Kea. There were times when the DLPs occurred every 12 minutes, as it was the case in June 2016, or even once every 7 minutes, in July 2000.
It could be the gas, not the ascending magma
A team of seismologists looked into that peculiar periodicity and discovered something pretty spectacular. It is commonly believed that earthquakes are caused by the ascension of magma. But the ongoing periodicity of Mauna Kea’s activity isn’t consistent with the theory.
Aaron Wech, a volcanologist at the U.S. Geological Survey’s Alaska Volcano Observatory in Anchorage, believes he has evidence that it wasn’t the ascension but the gases that did so. He calls this an “attractive alternative”.
It’s been 6,000 to 4,000 years since Mauna Kea last erupted. It takes about 250,000 years for the eruption rate to decrease until a volcano becomes completely silent. So, cooling magma is still boiling inside Mauna Kea.
In the boiling process, there is what volcanologists call a “second boiling”. When the gases accumulate, they need to release themselves from the pressuring magma. They creep into the cracks of the rock and pressure those cracks until they break up.
This is where the mumbling comes form. Or at least it could be since Wech said: “I don’t think it’s proof, but it’s good evidence.”