How can an event imprint itself upon the environment?

That's just a commonly repeated phrase ped around in paranormal enthusiast circles, but you're quite correct to ask this question. How can it? It's sounds vaguely scientific, but it's meant to sound that way. Like much of the paranormal "knowledge" ped around, it's only "sciencey" frosting and no actual cake. There is no testable hypothesis for how an event can imprint itself (whatever "imprint" is supposed to mean) on the environment (whatever "environment" is supposed to mean). So the answer to your question is it can't, it's just jargon.