Phreatic summit eruption seen by NASA satellite
Images obtained by the MAVEN satellite on July 10 2016 show a plume rising from the summit of Olympus Mons. The NASA press release states:
“Mars’ tallest volcano, Olympus Mons, appears as a prominent dark region near the top of the images, with a small white cloud at the summit that grows during the day. Olympus Mons appears dark because the volcano rises up above much of the hazy atmosphere which makes the rest of the planet appear lighter. The cloud is rising from one of the six summit craters.”
Scientists have now shown that it was caused by a phreatic explosion. They believe that it was triggered by the melting of ice on the summit, as global warming has now reached Mars.
The precise location of the eruption was found with a thermal imaging camera, THEMIS The image of the centre of the southernmost summit crater shows the trail of debris thrown out by the subsurface explosion, around a white-hot centre.
Regular monitoring has started in case the event repeats. Danger to the public is believed to be minimal but the airspace around the mountain, and the space above it, have been closed.