if they can survive 65000 years on the island I'm sure they have witnessed a few natural disasters and managed to survive as a culture.
Yes, you're right. The Jarwas can be seen up close with a few Government officials from India in this post Tsunami effort [1].
North andaman (Jarwa) tribes at the time were hostile, which I believe since the construction of the Andaman grand trunk road have become more subdued.
Compared to Jarwa, the sentilese have it better, they dont share their island.