Taphophobia: The medical term for the irrational fear of being buried alive.....
In the 17th and 18th centuries, the rate of individuals being buried alive was quite high....mostly due to the high number of people dying of diseases such as cholera, smallpox, etc.
Those dying of disease were generally not thoroughly examined to make sure they were truly dead out of fear of contamination.... They also tended to be buried quickly to prevent the spread of whatever disease they had contracted and led to their demise.
Taphophobia hit its peak in the 18th and 19th centuries and there are numerous documented cases of premature burials....
Some very famous people were actually taphophobics....including George Washington, Chopin, and Hans Christian Anderson. George instructed his attendants to not put his body in the vault any sooner than 3 days after he passed. (So, wonder no more why a "wake" is called a "wake" and bodies usually aren't buried immediately.) Chopin requested that he be cut open to make sure he wouldn't be alive when he was dead. And Anderson used to leave a card on his dresser every night before he went to bed saying "I am not really dead."
One of the saddest cases of premature interment occurred in the 1850's in South Carolina. A young girl, who was believed to have died of diphtheria, was buried in family's mausoleum. However, when her brother later died in the Civil War and the tomb was opened for his interment, the little girl's skeleton was found not where she had been laid to rest, but on the floor just behind the locked door.
The prevalence of the phenomena actually led to the invention of various versions of "safety coffins." These were coffins which were designed to either allow the "undeceased" to get out, or, more commonly to give them the ability to alert the outside world of the fact that they were still alive. One such device had a rope attached to a bell on the surface and to the deceased's hand in the coffin.....(Now you know where the term "dead ringer" comes from....)
In 1896, a group was formed called the "Society for the Prevention of People Being Buried Alive." One of the group's goals was to have a law passed that prohibited a body from being buried until strong putrefaction and smell were evident.
I take issue with the definition of taphophobia...
...I don't think there's anything "irrational" at all about it....