A seafloor mud volcano north of Norway is presenting researchers with an uncommon example of venting and is raising important questions. Seafloor aqueous vents, gas vents, mud volcanoes, and mud diapirs are found in a variety of geological settings. However, scientists did not expect to discover venting at the northern site, now known as the Haakon Mosby Mud Volcano (HMMV). It is considered especially unusual because of its Arctitc Location (72°N), its development largely within glacial marine sediments, and its lack of association either with salt tectonics or with plate subduction. Further, the volcano is posing questions for investigators about the relationship of methane generation and mud volcanism to thick, rapidly deposited sediments; sediment failure; and gas hydrates (GH).