National Geographic Channel is committed to live extreme-event programming. To that end, Nat Geo announced two such projects this morning on the first day of the TCA Summer TV Press Tour. Bob Ballard, aka “the guy who found the Titanic,” will make a dive into an underwater volcano off the coast of Granada. The volcano is so treacherous — a “ticking time bomb,” NatGeo calls it — that no ships are allowed within 10 miles of it, said National Geographic Channels CEO…