Sea Base 4

Sea Base 4 was a sea base in the ocean on planet Earth. It was active in 2084 as part of Sea Base Command. It had several weapons systems including energy tracers.

Staff included Solow, Vorshak, Nilson, Bulic, Maddox, Preston, and Karina.

In 2084 Sea Base 4 was involved in a conflict with the Sea Devils and the Silurians. Bulic was the only staff member to survive the attack. The Sea Devils and Silurians were killed by hexachromite gas released by the Fifth Doctor. (TV: Warriors of the Deep)

Behind the scenes
In The Doctor: His Lives and Times, a Breaking News tweet reports "Minister for Peace says world war is now 'inevitable' following discovery of wrecked Sea Base 'full of corpses'."