Other historic tsunamis have hit India - it isn't hard to find this on
the internet. This only accounts for the ones that have been
identified...many may have been either been too small, or misidentified
as storm surges/etc, to be recorded.

The northeast rim, in particular, of the Indian Ocean is very
seismically active - it is inconceivable that countless tsunami waves
have NOT spread across the sea south of India.

Bruce Jensen