From Pathfinder Adventure Path: Gatewalkers, which isn't enabled.

Cordon Alarm

HAZARD 2

Stealth +8 (trained)

Description A hempen rope tied between trees emanates an invisible, cylindrical barrier that sounds an alarm when crossed.

Disable DC 18 Thievery (trained) to move the rope without setting of the alarm, or Dispel Magic (1st rank; counteract DC 16) to disable the rope's magic

Alarm (primal)

Trigger An object or creature of at least 1 Bulk crosses an invisible vertical barrier extending 30 feet above and below the rope

Effect The rope squawks like an angry squirrel from the point where the barrier was breached. This alarm is as loud as a human scream and lasts for 1 minute. If an item or creature is still breaching the barrier at the end of this duration, the alarm immediately triggers again.

Reset The alarm resets immediately. Multiple breaches can cause the alarm to sound in multiple places at the same time, though the alarm can still be triggered only once per round.

Pathfinder Adventure Path: GatewalkersORC