After we found (hacked) the ETA puzzle and found about the floor safe, Cole sent out a team to check out the floor safe.
The where not able to crack the safe but found a message at the safe
First Update on ETA document
We found the floor safe, however it's locked and we won't be able to get a safecracker to open it for a few days. There's a sticky note reading "CR USGS Brass RM: ????".
Solution
Message "decoded":
CR = Clouds Rest
USGS = United States Geological Survey
Brass RM = Brass Reference Mark
Looking up the database of USGS for Clouds Rest led to this data:

as well as searching the internet gives a picure of the RM

This led to the safe combination
1956
Second update on ETA document
After we dent in the safe combination the ETA document was updated:
We discovered a list of time measurements labeled as "Resonance Location to Eta". We need some way to translate time measurements into something more useful.
Solution
We worked again on the formula of the ETA puzzle and finally got to this (see there):
km = ms * 300/24
Sending this to Cole led to the
Third update on ETA document
Good work everyone, we are sending a team to investigate a location in the North Pacific Ocean to see if there's any remnants of Eta. Further details in the next couple weeks if the investigations prove fruitful.