D&D 3.0: Tales from Mystara
Mount Xuria (AKA Mount Yuria) is a volcano located on Fletcher Island of the Archipelago of Ierendi. Local Makai people believe that a series of volcanic pillars near the coast are part of a " house of the sea gods ". They perform a fishing festival on those pillars once a year.
Under Mount Xuria there is a series of cave dwellings long ago used by Lizardmen. Tourist can visit the place and collect strange artifacts like arrowheads and pottery.
Mount Yuria is currently quiescent; it only goes off about once a century and usually dumps its lava westwards, slowly growing the island. When the lava goes east or south, mass panic and catastrophe tends to ensue.