Our crust is made of salt. Certain natural reactions cause salty crust to deteriorate. (One such substance is methane.)
Methane seeps out of the very bottom of the ocean, and also oil wells into the sea floor that aren't capped properly (I.e, BP oil spill in Gulf of Mexico)
Not saying it's that spill, but ONE of many causes of salt breakdown is methane.
Want DP delivered to your inbox daily? Subscribe here: