If you're willing to pay more for faster retrieval I guess you could store e.g. 5TB of random data to get a fast "base speed"- cutting those 3 days down to 12 hours.
Or use Nearline for archival data as well as disaster recovery. You won't need to transfer the archival data for normal disaster recovery scenarios, so it'll be -- for that scenario -- extra data that boosts your speed, but it's still, on its own, a useful use of the service.
That would be more expensive than just storing 1TB with the normal, full speed Cloud Storage service.