Conversation so far:
When did Harry Houdini perform his buried alive stunt?
The first was in 1915.
Where did Harry Houdini perform his first buried alive stunt?
The first was near Santa Ana, California.
What did Harry Houdini's first buried alive stunt involve?
Harry Houdini was buried, without a casket, in a pit of earth six feet deep.
How did Harry Houdini escape his first buried alive stunt?
Harry Houdini became exhausted and panicked while trying to dig his way to the surface and called for help. He had to be pulled from the grave by his assistants.
Why did Harry Houdini have to be pulled out of his first buried alive stunt?
When Harry Houdini's hand finally broke the surface, he fell unconscious.
Are there any other interesting aspects about the Harry Houdini article besides his first buried alive stunt?
Harry Houdini performed at least three variations on a buried alive stunt during his career.
Which variation of Harry Houdini's buried alive stunt were you describing before?
The first was near Santa Ana, California in 1915.

Question: What was the second variation?
Self-contained rewrite: What was the second variation of Harry Houdini's buried alive stunt?