Speak with the Endurance survivors until all conversation options with each of them are exhausted. They can be found at the following points in the game.

When Whitman helps Lara open a door with a Pry Axe upgrade, speak to him before opening that door.
Speak with Roth immediately after Lara gets the Climbing Axe,
Speak with Roth before investigating the smoke down the mountain.
Speak with Reyes, Sam and Jonas before leaving to check out the Galleaon, when Lara returns to Shipwreck Beach while there is daylight.
Speak with Reyes, Whitman, Jonah, and Sam on Shipwreck Beach before leaving to explore the Endurance crash.
Return to Shipwreck Beach and speak to Reyes, Jonah and Whitman just before leaving for the Research Base.