http://www.space.com/scienceastronomy/mars_vulcanism_041222.html<br /><br />"The European Space Agency's Mars Express orbiter photographed lava flows that must have occurred within the past two million years and imply, scientists say, that volcanoes on Mars might still pump molten rock to the surface now and then."<br /><br />If this article is correct that there were lava flows in the last 2 million years, the odds would be EXTREMELY small that all volcanic activity on Mars has now ceased. For volcanic activity to last for nearly 5 billion years, and then coincidentally stop within a geologic blink of time before we were there to see it, is very unlikely. <br /><br />The good news is that volcanic activity would be a valuable energy source to melt ice and provide energy for any microbe that might exist. The bad news is that it is now less likely (granted, it wasn't very likely to begin with) that the source of Mars methane is current biological activity.