obviously there's no way to be certain from that one photo, but...
it looks as though the break has happened as the right fork leg compressed more than the left. as I see it (non-expert disclaimer) this could happen if:
1. the landing involved a left to right force at the contact patch. eg off camber or bike was moving sideways or fork was 'crossed-up'.
2. the right fork leg landed on a rock (or something) before the wheel touched down.
3. the left leg was 'locked out' by damage/manufacturing defect/(other?)
it seems unlikely you wouldn't notice 2.. in 1., only the crossed-up option could impart the kind of forces needed whilst still feeling relatively gentle.
so my inner amateur Columbo says 'crossed-up' or left leg locked (however it may be)