You can always find a great treasure in a shrine's altar chamber. However, if you take the treasure with you this will displease the locals, you will lose 3 Standing and your action will trigger a catastrophe.
List of Aftermaths
If you look well enough you will see that the map contains hints about which aftermath might be triggered if you steal a treasure from the shrine.
|Map/Terrain||Island types • Regions • Terrain • Locations • Hazards • Prey Animals • Butterflies • Mysterious Fog • Shrine Aftermaths|
|Zones/Encounters||Attention Chance • Wandering Islanders • Wildlife • Enemies • Trader • Recruiter|
|Islanders||Standing • Tribe Types • Villages • Islander Huts • Wandering Islanders • Quests • Recruits|