Supervolcano forming under the Pacific
US: Life on Earth could be facing threat from a catastrophic
“supervolcano” which seismologists believe is due to erupt in 200
million years’ time. At least two “piles” of rock the size of continents
are crashing together as they shift at the bottom of Earth’s mantle,
2,900 km beneath the Pacific Ocean, researchers say.
“What we may be detecting is the start of one of these large eruptive
events that — if it ever happens — could cause very massive destruction
on Earth,” said seismologist Michael Thorne, the study’s principal
author and an assistant professor of geology and geophysics at the
University of Utah. However, disaster is not imminent. “This is the type
of mechanism that may generate massive plume eruptions,” he adds.
The new study, published in the journal Earth and Planetary Science
Letters, said the activity is creating a Florida-sized zone of partly
molten rock that may be the root of either of two kinds of massive
eruptions far in the future.
Hotspot plume supervolcano eruptions have caused huge landforms.
Gargantuan flood basalt eruptions that created “large igneous provinces”
like the Pacific Northwest’s Columbia River basalts 17 million to 15
million years ago, India’s Deccan Traps some 65 million years ago and
the Pacific’s huge Ontong Java Plateau basalts, which buried an
Alaska-sized area 125-199 million years ago.
Since the early 1990s, scientists have known of the existence of two
continent-sized “thermochemical piles” sitting atop Earth’s core and
beneath most of Earth’s volcanic hotspots — one under much of the South
Pacific and extending up to 20 degrees north latitude, and the other
under volcanically active Africa.
Using the highest-resolution method yet to make seismic images of the
core-mantle boundary, the team found evidence the pile under the Pacific
actually is the result of an ongoing collision between two or more
piles.
The Hindu |