what countries do tsunamis mostly occur
1 Where do tsunamis most often occur in the world? 2  Tsunamis occur most often in the Pacific Ocean and Indonesia because the Pacific Rim bordering the Ocean has a large number of active submarine earthquake zones. Where do tsunamis most often occur in the world? 2  Tsunamis occur most often in the Pacific Ocean and Indonesia because the Pacific Rim bordering the Ocean has a large number of active submarine earthquake zones.