[BlueStateBlues]

Any evidence of a double ring impact on earth?

[SunkenCiv]

Doublet impacts are common.

http://www.boulder.swri.edu/~bottke/clearwat.jpg

“Nearly 10% of the largest craters on Earth (including East and West Clearwater Lake in Canada, shown above) are doublets, formed by the nearly simultaneous impact of objects of comparable size.”

http://www.boulder.swri.edu/~bottke/

Crater chains:

http://www.boulder.swri.edu/~bottke/crater_chain/chain.html