Space.com has an article reporting that the Mars Express orbiter has found evidence that suggests volcanic activity on Mars may have occurred within the past 4 million years.

http://www.space.com/scienceastronomy/mars...ism_041222.html

With volcanic activiy could there also be some hot springs bubbling in some of those craters?

I'm surprised and confused by this story. Is "recent" activity in geologic
time (4m years) really an important data point to compare against the methane
observations?

Since methane degrades instantly (in a geologic time scale) we need instead
to see recent activity within a more human lifetime scale - we need to have
an orbiter spot a thermal signature on the surface. This hasn't happened
and we've been looking pretty hard.

It's nevertheless important because 4 million years ago is virtually present-day in geological terms -- if volcanoes were definitely erupting on Mars that short a time ago, it's an absolutely safe bet that the planet still has volcanic activity somewhere. Thus this evidence does provide solid further support to the belief that Mars has geothermally warmed areas which may be releasing methane either volcanically or biologically.

The ESA, however, is (not for the first time) falsely representing Mars Express as the first discoverer of such evidence, when in reality MGS' photos have been recognized for years as proving that some areas on Mars had volcanic activity only a few million years ago, as judged by their cratering. (William Hartmann has had a whole series of detailed abstracts on that subject at Lunar and Planetary Science Conference meetings.) The two areas where such activity seems most recent are the Tharsis volcanoes and the Athabasca Valley region (which also shows very clear evidence of recent gushings of liquid water across the surface from ice that was melted by that volcanic activity).