Yellowstone volcano rocked by THOUSANDS of tremors – reason why REVEALED

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Yellowstone volcano rocked by THOUSANDS of tremors – reason why REVEALED

The US scientific agency monitoring earthquakes made the shocking discovery while studying the swarm of tremors in Yellowstone National Park that characterised the summer of 2017. During that period, the edge of the park was hit by one the most “persistent earthquake swarms” ever observed in the area, according to David Shelly, seismologist at the USGS. Some 2,500 individual tremors have been registered in three months, with the biggest one reaching magnitude 4.4 on June 16 2017. 

This event, known as the 2017 Maple Creek swarm, has been driven by water rather than magma as it commonly happens.

Writing in Caldera Chronicles, a weekly column written by scientists and collaborators of the Observatory, Mr Shelley said: “Although movement of magma can sometimes generate earthquake swarms at volcanoes, the patterns of this swarm (especially the rapid migration and lack of nearby surface deformation) instead suggest that water is diffusing through small cracks in the subsurface.

“The involvement of this water may in part explain why these swarms are sometimes long-lived, why they expand dramatically over time, and why the fault structures are so complex.

“This also may explain why swarms are common in volcanic areas, where water is a byproduct released from deeper magma as it cools.


“We often see chemical evidence for this type of water at surface springs and fumaroles.

“Because this water is under great pressure in the deep crust where it is released, it tends to migrate upward and sometimes laterally.

“When it interacts with cooler, more brittle rocks stressed by tectonic and volcanic processes, this water may trigger earthquakes.

“In fact, themselves may allow the fluid to migrate more efficiently, through faults in the rock.” 

USGS scientists were able to come to this conclusion after studying the 2017 Maple Creek swarm with new advanced seismic technologies, which allowed them to “have more data than ever to detect and precisely locate earthquakes in the swarm, which can provide evidence of the causes of seismic swarms in the area”, as explained by Mr Shelley.

During this study involving the swarm, USGS scientists compared the waveforms of the thousands of recorded earthquakes rather than studying them individually, which allowed them to locate with more precision the locations of the earthquakes.

Mr Shelley added this technique allowed them to locate those small earthquakes that would have otherwise not been located if studied individually.

The super volcano located in Yellowstone park last erupted 664,000 years ago, but scientists still monitor it constantly, because its eruption would spark a worldwide catastrophe. 

A paper published four years ago in the scientific journal Geochemistry, Geophysics, Geosystems, argued the volcano would eject at least 240 cubic miles of material.

Then pyroclastic flows would hurl volcanic ash miles into the air and disperse it across United States.

The paper added that the northern Rockies would likely be buried by three feet of ash, while states including Wyoming, Idaho, Colorado, Montana, and Utah would.

Millions of people would be killed, together with plants and animals and massive destruction to infrastructure.

However, Mr Shelley offered some reassurance, saying earthquake swarms like this are “business as usual” for the caldera.     

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