Rupture in Lithosphere Driving Undersea Volcanism

Scientists analyzing a volcanic eruption at a mid – ocean ridge under the Pacific have come up with a somewhat contrarian explanation for what initiated it. Many scientists say undersea volcanism is triggered mainly by upwelling magma that reaches a critical pressure in the lithosphere and forces its way up. The new study says the dominant force, at least in this case, was the seafloor itself – basically that it ripped itself open, allowing magma to spill out. The eruption took place on the East Pacific Rise, some 700 miles off Mexico.

magma-rifts

“Mid – ocean ridges are commonly viewed as seafloor volcanoes, operating like volcanoes on land,” said the study’s lead author, Yen Joe Tan, a graduate student at Columbia University’s Lamont – Doherty Earth Observatory. “We’re saying they should actually be viewed as tears in the crust, where magma oozes out.” The study appears in the journal Nature this week.

axial-seamount

The authors of the new paper took another look after a 2015 eruption at an unconnected study site, at Axial Seamount, off the coast of Oregon. Unlike the earlier East Pacific Rise eruption, this one was studied in real time with an assortment of instruments. Among the data produced were recordings of violent popping noises that appeared related to the emergence of lava on the seafloor – possibly the result of exploding gas bubbles, or implosions of hardening lava.

In light of the Axial Seamount observations, the researchers reviewed the 2005 – 2006 data from the East Pacific Rise, and came up with a newly sharpened picture. Their reanalysis suggested that most of the eruption took place rapidly, not over months. Other researchers had already identified a series of conventional earthquakes of about magnitude 2 on Jan. 22, 2006, of the kind usually associated with the rupture of a rock boundary, along a 35 – kilometer – long segment of the ridge. About 15 minutes later, the seismometers started picking up clusters of lower – frequency earthquakes, of a type usually associated with rising magma. Another hour or two on, popping sounds like those heard at Axial Seamount appeared, in four separate areas along the segment, each in an area about 5 kilometers long.

mantle-plumes

“It’s been a kind of chicken – and – egg question,” said coauthor Maya Tolstoy, a marine geophysicist at Lamont – Doherty. “You have these two different forces [magma vs. tectonics] that could play a role, and it’s hard to tell which triggers the eruption. Here, we can make the argument for one dominating, because we see this series of events, and then multiple magma chambers erupting at the same time.”

The authors say that according to their observations, about 85 percent of the lava emerged within two days, with remnants dribbling out over the course of a week. The eruptions produced some 22 million cubic meters of seafloor – about enough to cover 13 football fields 1,000 feet deep.

Cynthia Ebinger, a professor at the University of Rochester who studies eruptions at spreading sites both on land and under the ocean, said in an email that very few seafloor eruptions have been so directly observed. The study “adds a new factor to consider,” she said. “It shows that tectonic stresses can trigger large – volume intrusions and eruptions” to create new seafloor.

lithoshphere11

Michael Perfit, a professor at the University of Florida who also studies undersea eruptions, said the study “tells a remarkable story.” But, he said, the authors may have overstated the relative role of tectonic stress versus magma pressure. “I think it’s really got to be both,” he said. He cited a 2014 geochemical study he coauthored suggesting that the magma was replenished with new material from below about 6 weeks before the eruption. This suggests pressure could have played a more substantial role, he said.

______________

_soc-initiative-banner_sm

Thanks to you who have pitched in. News is popping and we plan to be here with our ability to highlight and navigate in a way you can understand – then further your ability to discern how these new scientific discoveries can have a ‘real-time’ effect in our lives.  Cheers, Mitch

give-gain-grow

Help us maintain our ability to deliver our findings to a large interested community who has a sense of our direction and the value it brings to both novice and expert alike.

The following link takes you to a page where you can use a drop-down menu to choose from a list of tributes. – CLICK HERE 

 

Author: Mitch Battros

Mitch Battros is a scientific journalist who is highly respected in both the scientific and spiritual communities due to his unique ability to bridge the gap between modern science and ancient text. Founded in 1995 – Earth Changes TV was born with Battros as its creator and chief editor for his syndicated television show. In 2003, he switched to a weekly radio show as Earth Changes Media. ECM quickly found its way in becoming a top source for news and discoveries in the scientific fields of astrophysics, space weather, earth science, and ancient text. Seeing the need to venture beyond the Sun-Earth connection, in 2016 Battros advanced his studies which incorporates our galaxy Milky Way – and its seemingly rhythmic cycles directly connected to our Solar System, Sun, and Earth driven by the source of charged particles such as galactic cosmic rays, gamma rays, and solar rays. Now, “Science Of Cycles” is the vehicle which brings the latest cutting-edge discoveries confirming his published Equation.