How do void echo crits work?

If a skill crits (for example if I Erasing Strike and it crits) does the echo crit as well, or does it have a separate crit chance? Thanks.

not sure on the mechanics but i’m pretty sure today i saw an echo crit when the main one hadn’t - i think it was when i’d done a void cleave between the main hit and the echo, so might’ve proc’d Obliterator