Great article on Horror and Atrocity!!!
My experience and education in this area has taught me a few things about horror, atrocity and especially disaster. I kind of put them all together because to me, they are about the same thing.
Disaster is a situation whose distructive power taxes the local infrastructure beyond its ability to mitigate or prepare for, as well as effectively respond to. A Tsunami is not a disaster in itself. If the waves crashed in against a deserted island, or uninhabited stretch of continental coast, it may be distructive to the sand, the trees and the underbrush, but it would not reach the status of "disaster" unless it destroyed that swath of earth's ability to grow trees and underbrush. Even then, most of us wouldn't consider it a disaster because, well if the trees fell and there was nothing and no one to hear it, would it make a sound??? right?
Horror, would be the same type of situation as disaster, except the assets and infrastructure in question would be of a personal nature. This is different for everyone, depending on personal constitution, experience and expectation. No matter how horrific (or innocuous) an event may seem to some of us, it would have the opposite effect on others. For example, for most people, no matter how much protective gear they wore, they would never be able to get themselves to run into a burning building. However, for the fire fighter, it not only isn't a problem, it is something to which they look forward. Watch almost any firefighter (especially younger ones) when they get a little smoke in their nose. There is almost an intoxicating affect.
Attrocity would be a person (or group of people) inflicting horror on another person (or group). Again, the defining aspect would be taking the person beyond their ability to deal with. Torture, rape, and murder would be examples of inflicting horror upon individuals; while Slavery, Holocaust and Genocide would be examples of generalized, or institutionalized horror. In either case what seperates the attrocity from the horror is one refers to the perpetrator, while the other refers to the victims.
Most people will never truly experience horror on a first hand basis. We are taken through the process as a 3rd party observer, feeling the requisite Denial, Anger, Bargaining, Depression and Acceptance by proxy for those whose faces fill space on newspapers and websites, TV screens and radio airwaves. Of course, a well written book or well produced film can take us for the same ride, and in the minds of most people, the emotions are equally easy to shake off when the images are no longer in view.