You gotta consult someone who KNOWS JAPANESE AND LIVES IN JAPAN to translate the names of things *cough* not me but someone like me *cough* before the official English versions come out.
I saw "earthquake spiral" scrolling though Bulbapedia and thought: FAIL.
"Jishin" is "self belief" i.e. "ego" in Japanese (yes it also means earthquake with different Kanji).
The full phrase "jishinkajou" means: overconfidence
Does that make sense? As you defeat each opponent, you think you are stronger (and in fact are, for the length of the battle) and become overconfident.
"Earthquake spiral" makes no sense. Please fix it.