Maybe hard for surveillance though? A single railcar of liquid is 100 tons (I don't know if liquid methane is shipped, this is just a way to visualize - and this is a rough number. Methane is about 12 pct lighter than water.)

I wonder what the most likely reasons are. I might think a fracking based earthquake opening up an underground reservoir that feeds into a mine? But that is very speculative! I am assuming there are no chemical plants in the area.

For context [0] says global annual methane generation is ~570E6 tons, which puts hourly production at 570E6/(24*365)~=65000 or over a thousand times this source. Like, not /great/ definitely want to address. But unless it's a symptom of a new mechanism I don't know if I should be super alarmed.

[0] https://www.iea.org/reports/methane-tracker-2020