What is "skyquake"

Skyquakes or mystery booms are unexplained reports of a phenomenon that sounds like a cannon or a sonic boom coming from the sky. They have been heard in several locations around the world such as the banks of the river Ganges in India, the East Coast and inland Finger Lakes of the United States, as well as areas of the North Sea, Japan, Italy and in Drogheda, Ireland.

Skyquake is the name of several fictional characters from the various Transformers universes.