I saw that movie about 52 years ago. I found it on DVD and it is still a good movie!
I don’t think pumping water into a volcano is a good idea. The water will flash to steam, and the pressure has no place to go.
In the book THE MYSTERIOUS ISLAND, it blew when sea water was found leaking into the volcano, and I believe Krakatoa blew for the same reason.
Sizing is your friend...
I remember seeing this film as a kid!
I thought it was a pretty cool film then.
I can actually say I’ve seen that movie...