Which volcano is the second highest in Antarctica as well as the most southerly active volcano on Earth?

Mt. Erebus is recognized as the second highest volcano in Antarctica, standing at approximately 3,794 meters (12,448 feet) above sea level. It also holds the distinction of being the most active volcano in Antarctica and the most southerly active volcano on the planet. Its continuous volcanic activity is observable with the presence of a persistent lava lake at the summit, which has been a notable feature since the 1970s.

The significance of Mt. Erebus in both height and activity sets it apart in Antarctica and globally, making it a focal point for volcanology and geological studies. Understanding its behavior contributes substantially to our comprehension of volcanic activity in polar regions, which can differ from that in more temperate zones due to unique environmental conditions.

In contrast, while Mt. Sidley is an important volcanic feature in Antarctica, it does not match the volcanic activity level or prominence of Mt. Erebus. Mt. Everest and K2 are towering peaks, but they are not volcanoes, which directly disqualifies them from relevance to this question.