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Geodimeter measurements of slip and strain accumulation along the San Andreas fault Geodimeter measurements of slip and strain accumulation along the San Andreas fault

The U.S. Geological Survey conducts repeated geodimeter surveys of trilateration networks in central California in order to study the processes of slip and strain accumulation along the San Andreas fault. The precision of distance measurement is described by a standard deviation σ = (a2+ b2L2)12 where a = (a2+ b2L2)12 where a = 3mm, b = 2 · 10−7, and L is the line length. Within the...
Authors
J.C. Savage, W.H. Prescott

Gravity measurements in the vicinity of Georges Bank Gravity measurements in the vicinity of Georges Bank

A total of 97 new bottom gravity measurements on the continental shelf in the vicinity of Georges Bank was reduced to the simple Bouguer anomaly, using a density of 2.80 gm per cm3 for the correction. Results help substantiate the presence of mafic and felsic intrusive bodies along the northern edge of the bank. A gravity low near the center of the bank, trending northeast, corresponds...
Authors
John D. Hendricks, James D. Robb

Interstitial water studies on small core samples, Leg 15 Interstitial water studies on small core samples, Leg 15

Analyses of pore fluids from reducing environments demonstrate that reduction of SO4 is accompanied by large increases in alkalinity and strong depletion of Ca and Mg. The data are compatible with a model of replacement of Fe3+ in clay lattices by Mg from the interstitial solutions and the precipitation of pyrite. Depletions of Na in the interstitial solutions are related to Mg losses by...
Authors
Fred L. Sayles, Frank T. Manheim, Lee S. Waterman

Energy and plane waves in linear viscoelastic media Energy and plane waves in linear viscoelastic media

The mathematical framework for describing plane waves in elastic and linear anelastic media is presented. Theoretical results suggest that the nature of plane waves in anelastic materials is distinctly different from the nature of plane waves in elastic materials. In elastic media the only type of inhomogeneous plane wave (P or S) that can propagate is one for which planes of constant...
Authors
Roger D. Borcherdt
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