Daniel Dzurisin W.P. Elder R. W. Saltus Robert C. Jachens 1983 Reoccupiable precision gravity networks for the purpose of monitoring volcanic activity were established in the vicinity of Lassen Peak and Mt. Shasta. Base-line measurements were made during the summer of 1981, nearly coincident in time with other base-line geodetic measurements. The gravity surveys yielded gravity values at network stations relative to local bases with typical uncertainties of 0.007 mGal (1 computed standard error). application/pdf 10.3133/ofr83192 en U.S. Geological Survey, Precision gravity networks at Lassen Peak and Mount Shasta, California reports