Evidence Venus is volcanically active – Zoo House News

Venus appears to be experiencing volcanic activity, according to new research that provides strong evidence to answer the ongoing question of whether Earth’s sister planet is currently experiencing eruptions and lava flows.

Although Venus is similar in size and mass to Earth, it differs significantly in that it lacks plate tectonics. The boundaries of the Earth’s moving surface plates are the main sites of volcanic activity.

New research by University of Alaska Fairbanks Geophysical Institute research professor Robert Herrick revealed a nearly 1-square-mile volcanic vent that was changing shape and growing over eight months in 1991. Changes of this magnitude on Earth are associated with volcanic activity, whether through an eruption at the vent or movement of magma below the vent, causing the vent walls to collapse and the vent to expand.

The research results were published today in the journal Science.

Herrick studied images taken during the first two acquisition cycles of NASA’s Magellan spacecraft in the early 1990s. Until recently, comparing digital images to find new lava flows took too long, the paper notes. As a result, few scientists have searched Magellan data for feature formation.

“It was only in the last decade that Magellan data was truly available in full resolution, mosaicked, and easily manipulated by an investigator with a typical personal workstation,” Herrick said.

The new research focused on an area containing two of Venus’ largest volcanoes, Ozza and Maat Mons.

“Ozza and Maat Mons are comparable in volume to the largest volcanoes on Earth, but have lower slopes and are therefore more widespread,” Herrick said.

Maat Mons contains the expanded vent indicating volcanic activity.

Herrick compared a Magellanic image taken in mid-February 1991 with an image taken in mid-October 1991 and noticed a change in a vent on the north face of a domed shield volcano that is part of Maat Mons volcano.

The vent had grown from a circular formation just under 1 square mile to an irregular shape of about 1.5 square miles.

The later picture shows that the walls of the chimney were getting shorter, maybe only a few hundred feet high, and that the chimney was almost filled to the brim. The researchers speculate that a lake of lava formed in the vent in the eight months between recordings, although it is not known whether the contents were liquid or cooled and solidified.

The researchers offer a caveat: Nonvolcanic, earthquake-induced collapse of the vent’s walls may have caused the expansion. However, they note that vent collapses of this magnitude on Earth’s volcanoes have always been accompanied by nearby volcanic eruptions; Magma is retreating under the vent because it’s going somewhere else.

Venus’s surface is geologically young, especially when compared to all other rock bodies except Earth and Jupiter’s moon Io, Herrick said.

“However, estimates of how often eruptions might occur on Venus have been speculative, ranging from several large eruptions per year to one such eruption every few or even ten years,” he said.

Herrick contrasts the lack of information about Venus’ volcanism with what is known about Jupiter’s moon Io and about Mars.

“Io is so active that multiple ongoing eruptions have been imaged every time we’ve observed it,” he said.

On a geologic timescale, relatively young lava flows suggest Mars remains volcanically active, Herrick said.

“However, nothing has happened in the 45 years that we have been observing Mars, and most scientists would say that one would have to observe the surface for probably a few million years to have any reasonable chance of seeing a new lava flow. ” he said.

Herrick’s research adds Venus to the small pool of volcanically active bodies in our solar system.

“We can now say that Venus is currently volcanically active, in the sense that there are at least a couple of eruptions per year,” he said. “We can expect that the upcoming Venus missions will observe new volcanic flows that have occurred since the end of the Magellan mission three decades ago, and we should monitor some activity while the two upcoming orbital missions collect imagery.”

Co-author Scott Hensley of NASA’s Jet Propulsion Laboratory performed the modeling for the research.