The following information obtained from UNAVCO's online DOI system:
(https://www.unavco.org/data/doi/search/search.html)

USGS Shake Alert GPS Network - AGNS-AgnessRR__OR2021 P.S.
Start: 17-Jun-2021
End: 14-Nov-2022
Brooks, Benjamin, 2021, USGS Shake Alert GPS Network - AGNS-AgnessRR__OR2021 P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/STR6-MJ70