[Flerdle] No
[Iroul] No

OK - to summarise those things which might help:
It is found on earth (though earth is not part of the answer - which is more than one word), it is broadly to do with geology, it is part of mainstream science, it cannot be perceived without instruments, it doesn't exist on the moon and not as such on other planets, it is not an event nor anything to do with weather (though that might have got the audience murmuring as well).
You've been concentrating a lot on what - there may be other productive lines of enquiry.

[Flerdle] No (but that's partly because of the specific description)