VOLCANISM ON VENUS
There is much volcanism on Venus. Many are high peaks with
extensive lava flows . The volcanoes are shield volcanoes, like
the Hawaiian islands. This type of volcano indicates a very
fluid lava. No active volcanoes have been found on Venus to
date but evidence seems to suggest that some do
exist.
- Gula Mons is a massive shield volcano on
Venus. The caldera at the summit is over 100 km across. The
volcano is about 4 km high. This image was produced by the 3D
imaging of Magellan. Vertical scale is greatly
exaggerated.
There are two pieces
of evidence that point to volcanism still taking place on
Venus. Levels of sulfur dioxide in the atmosphere show
variations. One spacecraft measured very high levels of sulfur
dioxide but levels dropped off over time. Sulfur dioxide is a
gas commonly released in volcanic eruptions. On Earth, when a
volcano erupts, our atmospheric levels of this gas rise.
Another bit of evidence is that two orbiters have measured
bursts of radio energy on Venus. These bursts are similar to
those produced by lightning discharges which often occur in
the plumes of erupting volcanoes.
These volcanic lava domes are found on the
southeast edge of Alpha Regio. They occur when molten rock
emerges out of the ground and then retreats, leaving a thin
solid crust such as this.
This view of the lava domes is from the 3D
imager used by the Magellan spacecraft.
