The elevation of the lowest level of the caldera is the same as the base of the volcano; however, the original lower slopes of Albor Tholus may have been covered by lava flows from its larger neighbor, Elysium Mons. Evaluations by the Mars probe Mars Express found that the volcanoes of the Elysium region were active over long periods.
The caldera's floor reaches at the same level as the volcano's base; yet, the original lower slopes of Albor Tholus might have been covered by lava flows from its larger neighbor, Elysium Mons. Evaluations conducted by the Mars probe Mars Express revealed that volcanoes in the Elysium region were active over long durations.