Earth has had some whoppers of volcanic explosions in the past, including one that may have been half of the one-two punch that led to the extinction of dinosaurs. But Mars can easily blow any of that away. It once had a volcanic eruption so huge, that it tilted the entire face of the planet by 25 degrees.
Sometime 3.5 billion to 3 billion years ago, when the planet was still wetter and warmer than it is today, the largest volcano in the solar system exploded. That volcano—the Tharsis volcanic dome—is 96.3 miles by 77.7 miles. When it exploded all those years ago, it disrupted the mantle and crust of the planet (though not the rest of the interior), shifting the whole outside crust up 25 degrees. When the volcano exploded, it did so with a mass of a "billion billion" metric tons of matter, or 1,000,000,000,000,000,000 metric tons.
This event may have also created the ancient riverbeds we see today by redirecting water flow. It also explains why there are water ice "glaciers" underground far from the poles of the planet, and why the Tharsis Tholus is located near the equator today. The results of the study from Géosciences Paris Sud, Géosciences Environnement Toulouse, Laboratoire de Météorologie Dynamique, and the Lunar and Planetary Laboratory at the University of Arizona were published yesterday in Nature .
Source: Nature