Gallows Humour - Coping With Death (and Disaster)

In times of great tragedy or trauma, such as the Space Shuttle Challenger disaster in 1986, or more-recent events like the World Trade Centre tragedy in 2001 (9/11) or a tremendously huge natural disaster like the recent earthquake in Japan, some people can lack the capacity to deal effectively or appropriately with trauma of that scale.
Don't worry... if you find yourself cracking somewhat-inappropriate jokes about Godzilla in the next few weeks as Japan's nuclear reactors melt, you're not alone... and apparently it's a normal reaction to an unnatural situation.
Some people just can't wrap their heads around a hugely traumatic event and are unprepared for the sheer level of emotion that might seek to overwhelm them. And they aren't alone.
The term 'gallows humour' has only been around since 1901 or so... but it has existed in one form or another for much longer:

From William Shakespeare's play Romeo and Juliet (Act 3, Scene 1):

Mercutio is stabbed in a swordfight by Tybalt, Juliet's cousin:

Romeo: "Courage, man; the hurt cannot be much."

Mercutio: "No, 'tis not so deep as a well, nor so wide as a church-door; but 'tis enough, 'twill serve: ask for me to-morrow, and you shall find me a grave man."

. . . . . .

A condemned man is being led into the execution chamber. The condemned prisoner points to the electric chair and asks the prison warden: "Are you sure this thing's safe?".