[OmegaVanity]

This doesn't seem promising, but it's better than no explination at all:

A residual haunting is a playback of a past event. The apparitions involved are not spirits, they are "recordings" of the event. I believe that this will be the first type of haunting that main stream researchers will recognize and study. There are numerous theories on how these residual hauntings come to be. The main one will be discussed here.

Video and audio tapes capture sounds and images on a film of special material that has been oxidized or rusted. Certain building materials, such as slate used in older castles and stone structures and iron nails used in many older buildings, have properties similar to that of the tapes. When a traumatic event occurs or a time of heightened emotions, these materials record the event for future playback. Everything is made up of energy and energy cannot be destroyed. The materials store the energy created by these traumatic events and plays them back at a later time. We are not sure what causes the playback of the events, that still remains a mystery. Is it the right weather conditions, the witness's energy or sensitivity or some type of energy release?

Residual energy imprint hauntings are often called 'residual energy hauntings' or 'imprints'--which are the products of an emotional incident, often a violent event.

Just like an iron remains hot long after it's turned off, strong energy seems to be stored in physical surroundings. When someone witnesses this kind of haunting and is startled or frightened by it, that energy may refuel the setting so that the manifestations and/or impressions continue.

This may also account for the phenomena of haunted objects.