AF0

AF0 refers to a specific classification within the Modified Mercalli Intensity (MMI) scale, which measures the intensity of an earthquake at a particular location. The MMI scale is a subjective scale that describes the effects of seismic shaking on people, buildings, and the environment. AF0 is the lowest level of intensity on this scale. An earthquake intensity of AF0 signifies that the earthquake was not felt by most people. Only in very exceptional circumstances might some individuals, particularly those in lower floors or particularly sensitive to vibrations, report feeling a slight tremor. There are typically no observable effects on the environment or structures at this intensity level. AF0 is often associated with very small, minor earthquakes that are too weak to be widely perceived. It is important to distinguish earthquake intensity, which describes the local effects of an earthquake, from earthquake magnitude, which measures the energy released at the earthquake's source.