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

Plutons GPS Network - LLST-Lastarria Volcano P.S.
Start: 06-Nov-2010
End: 12-Aug-2015
Pritchard, Matt, 2011, Plutons GPS Network - LLST-Lastarria Volcano P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5707ZHZ