How to get a diffrent locale for rotten vale

[Lava_Giant]

Hello,

Im trying to get the ancient fossil upsurge in rotten vale.
But its not among the choices in low and high rank expeditions.

Is there a way to change it?

[Damage1710]

Investigations can influence upsurges,
Other than that it's random

[Lava_Giant]

does the local change after every successful assigned,optional quest? Does an expedition could also reroll the locales of the maps ?

[Damage1710]

it changes on quest completion, or returning from expedition, but I'm not entirely sure

[Bobucles]

random surges are random. Just keep doing quests and check the map from time to time.
Investigations have a specific surge attached to them. Some quests may also have a specific surge.