A comparable ocean impact would be the 2004 Indian Ocean earthquake, which was about 3x more energetic.
Earthquakes' energy doesn't all go to displacing water and hence generating tsunamis. An ocean impact is significantly more efficient at transferring energy into tsunamis.
https://www.sciencedirect.com/science/article/abs/pii/B97804...
https://web.archive.org/web/20100404013939/http://neic.usgs....