Alaska is prone, as is Siberia, to having its permafrost layer shattered. This firm layer of frozen soil, often saturated with water so that it is essentially ice in places, resists change in the topography, so that the soil does not pour into lowering areas, or push up under pressure from below, and thus tension and stress accumulate over time. Just as plates resist change, and break suddenly during earthquakes along their edges where they are scraping or pressing against each other, in a like manner, permafrost snaps and is accompanied by minor earthquakes. These earthquakes are barely perceptible, but can be recorded by instruments.
Such snaps can occur due to impact of small meteors, or when a fireball comes close to the surface during its intense burning. Heated air causes this air above the permafrost to become lighter and less dense, and in addition can soften or melt the permafrost. Pressure points that already existed are then given an opening, and create a snap in such close relationship to the sighting of the meteor that nearby observers assume an impact when none might have occurred.