Wednesday, August 5, 2015

Best evidence yet for active volcanism on Venus?


In an article from Geophysical Research Letters, a team led by Eugene Shaygin used images taken by the Venus Monitoring Camera (VMC) aboard Venus Express to identify transient hot spots on the surface. These hot spots are located near very young (~10 Mya) volcanoes and rifts, and are suggestive of active lava flows.

Even though the surface is generally obscured from view by the thick clouds, there is a transparent window through which light can pass in the near infrared wavelengths, and the VMC can capture images near 1 μm.

What Did They Find?

Examining VMC images of the Atla Regio region, the research team identified bright spots, i.e., areas where the local emissivity was significantly higher. These hot spots were first seen in VMC images from June 2008, and were gone again by October.

VMC images of Ganiki Chasma showing transient hot spots
They believe they have eliminated other possible sources for these hot spots, and they are confident the spots represent an increase in the surface temperature.

As additional supporting evidence, they point to Magellan spacecraft radar imagery.  Radar-dark parabolas are seen around impact craters on Venus, and are understood to represent deposited ejecta from the impact (more here in this paper by Campbell et al.). These parabolas are associated with the youngest impact craters, and believed to be among the youngest visible features on the planet. Magellan images of the same location show that the ejecta parabola associated with crater Stillwell is interrupted by what could be lighter colored lava flows that would post-date the fairly recent ejecta.

The authors believe these hot spots are volcanic in origin, and the body of evidence suggests that Venus is currently geodynamically active.

Why Is It Important?

If there are active volcanoes on Venus, it would be invaluable for future comparative studies of rocky worlds with ongoing volcanism. It could shed light on why the Earth and Venus evolved so differently, and help us learn more about the Earth in the process.


Shalygin, E., Markiewicz, W., Basilevsky, A., Titov, D., Ignatiev, N., & Head, J. (2015). Active volcanism on Venus in the Ganiki Chasma rift zone Geophysical Research Letters, 42 (12), 4762-4769 DOI: 10.1002/2015GL064088

Campbell, B., Campbell, D., Morgan, G., Carter, L., Nolan, M., & Chandler, J. (2015). Evidence for crater ejecta on Venus tessera terrain from Earth-based radar images Icarus, 250, 123-130 DOI: 10.1016/j.icarus.2014.11.025

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