Last month, the research institute at the colony and Celestial City lab determined the appropriate frequency through collaboration.
The modified seismic wave excitation device would continuously transmit seismic waves of twelve different frequencies to create a "blank domain" with a range of ten kilometers underground. In this blank domain, Devil Worms would be unable to determine their direction and unable to distinguish the surrounding and surface conditions, while also experiencing strong discomfort.
The experts in the lab named the invention Ultrasonic Fence.
Twelve seismic wave excitation devices were deployed around the colony to form an ultrasonic fence. Now, with the colony as the center, the ten kilometers radius became a restricted zone for Devil Worms.
Thanks to this, the stagnant work around the colony finally restarted.
