I just spoke with the owner of the Samba a few minutes ago - he reported that the 16 passenger tourist superior ship Guantanamera exploded while anchored in Academy Bay last night (this is right in Puerto Ayora). He was in the Santa Cruz highlands, and reported having heard the explosion from there. The guess is that gas from a leaking propane tank ignited. Apparently, the engineer is missing, while one crew member is in hospital with a broken leg. No other people were on board.
He also informed that the Astrea, a live-aboard dive ship (which also does some regular naturalist cruises) ran aground earlier this month while navigating in the islands. No one was injured, and the ship was successfully removed with little hull damage, but it will likely be out of service for repairs for the next several months.
What with the fire aboard the Queen Beatriz earlier this month (while it was in dry dock undergoing annual maintenance), that's three ships out of service.
If you were scheduled to sail on any of these ships, I would recommend that you get in touch with your agent to discuss alternatives as soon as possible.