I agree that the media dwells on events that will catch the attention of the public. They go for the shock value of events. Once that particular event has died down, they move on to the next one.
It is important that people stay current on what is going on in the world though. For example, because of the huge media coverage of the earthquake in Haiti, they received millions upon millions of dollars in aide not to mention food, water, clothing, medicine, etc.
Yes, to some degree, although I think the media does this more with human and natural disasters. Some call it "disaster porn" in that, in the case of the Haiti earthquake for example, people are glued to news stations 'round the clock coverage and on the spot reporting so they can witness the devastation and tragedy like it's a reality show, without having to live through it. Then once the novelty wears off, we move on to other things. In the case of violence in the US, take the recent "Times Square Bomber" who was so blazingly incompetent, I doubt he can be called a terrorist, but from the media's perspective, you'd have thought he was Osama bin Laden's protege.
Violence is sensational, and since the dawn of time, it has "sold." Consider early literary works--Greek plays, Egyptian myths, etc.; almost all of them contain seemingly gratuitous violence. The same is true of the media, and in recent times since many media outlets have veered farther away from factual journalism, they have also exhibited a tendency to "over-cover" violent or other sensational occurrences. One truth that we cannot ignore, however, is that it is almost impossible for a human to remain completely objective on any topic--speaking tone, facial gestures, natural human responses--all of these play into a person's interpretation of a true-life incident.
The media exaggerates violence in our society today by giving violent events more coverage than other sorts of events that happen more frequently than violent events do. There's a well known local TV news saying "if it bleeds, it leads," with the idea being that a story with violence will go on the news right at the beginning. So the answer to the "how" part of your question is that they do it by putting the stories in more prominent parts of the newscast or newspaper and by running those stories for longer than other kinds of stories.
The reason for this is that people seem to prefer watching accounts of violence (and of disasters and things like that). These types of events seem way more interesting to the public than stories about good things happening. So the answer to the "why" is because viewers seem to prefer those stories and so media outlets that need to make a profit have to show them.
Because of this, we see more stories about violence than would be warranted by the amount of violence that actually occurs.
Some links: http://pediatrics.aappublications.org/cgi/content/full/113/6/1771#ABS (some stuff about how there's too much violence)
http://www.commercialappeal.com/news/2009/jun/10/tv-news-dealing-overdose-of (looks at both the issue of there being too much and the idea that it happens because of the need to make profit)
The media now has a greater agenda-to make money. To make more money, they would have to grab more attention. News of bad events, like events of violence, grab our attention, and so an exaggeration of the violence will make us fascinated and intrigued and interested, which will, as a result, make the media profits.
I don't think the media exaggerate violent events but if you look at the events from an anomaly perspective: that violence is an aberration in society therefore it is always given the most coverage. Violence destroys so many things: people, property, etc. It deserves its place on newscasts and it is always prominently covered because of what it is.
When media publishes only such news that sells, we cannot point fingers at them. They are doing what every other business is doing. But what is definitely wrong is the way they misrepresent the fact by selective disclosure and artful use of language.They represent things not the way they are but in a form that has been altered to make it more attractive and sensationalized. In this way they are really selling spurious goods. This is definitely unethical and a form of cheating.
And they do this kind of selective and "window dressed" reporting only in case of violence, but in everything they report.
Because it sells. The public wants to watch disasters, wars and action; not peace-talks, financial discussions and reasons.
Eg. During the last 12 months we have suffered a financial crises on a scale that it practically unprecedented and the global economy almost collapsed back into the stone age.But you wouldn't really know it by looking at the mainstream media because the story is complex, depressing, boring and non-visual.
Now, a plane crash... they love those. It's sooo dramatic.