The scanner will stop on an active frequency strong enough to break the radio's squelch setting and resume scanning other frequencies when that activity ceases.

For example, brain death, as practiced in medical science, defines death as a point in time at which brain activity ceases.

The activity of the activator generally increases with temperature, up to a certain value where activity ceases, either due to thermal decomposition or excessive volatilization.

Then activity ceases completely for several years.