DO NOT MESS WITH PERMA FROST.
In Siberia in an area the size of the USA is perma frost and underneath it, not very deep under it ,is METHANE GAS . dig a hole where ever you like in it , throw a flame into it and stand back because you are likely to get your head blown off.
Here's the worrying bit; due to global warming the frost is melting and scientists are worried that if global warming accelerates the whole lot will go up .
Don't say I didn't warn you, it must be true I have just seen it on a television documentry.Now imagine all that methane escaping in the Kingdumb Hall as they reach down through their brains .Nope I would stay well clear of the hall until they find a way of burning off the gas safely.