Catastrophic fluid escape venting-tunnels and related features associated with large submarine slides on the continental rise off Vesterålen-Troms, North Norway

► Large seabed tunnels are related to dewatering and possibly gas reservoir venting. ► Small tunnels are formed by dewatering and/or gas hydrate decomposition. ► Chimney tunnels, carbonate crusts and bacterial mats on the seabed show active seep.