It's been inactive for millions of years, and 'It rivals in size some of the largest volcanoes in the solar system, such as Olympus Mons on Mars.' I assume, if it became active again and erupted, it could change land masses, creating new ones and flooding others? Instead of Waterworld, it could be the total opposite! Maybe the waters would go underground, like on other planets?
Here is the article-
http://www.sci-news.com/othersciences/geophysics/science-tamu-massif-largest-volcano-pacific-01366.html
Here is the article-
http://www.sci-news.com/othersciences/geophysics/science-tamu-massif-largest-volcano-pacific-01366.html