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Effects of local geology on ground motion in the San Francisco Bay region, California: A continued study

Measurements of ground motion generated by nuclear explosions in Nevada have been completed for 99 locations in the San Francisco Bay region, California. The seismograms, Fourier amplitude spectra, spectral amplification curves for the signal, and the Fourier amplitude spectra of the seismic noise are presented for 60 locations. Analog amplifications, based on the maximum signal amplitude, are com
Authors
James F. Gibbs, Roger D. Borcherdt

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 to the Geor
Authors
John D. Hendricks, James D. Robb

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 a ratio o
Authors
Fred L. Sayles, Frank T. Manheim, Lee S. Waterman