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Tilt measurements at Long Valley caldera, California, May-August 1982

The Mammoth Lakes area in east-central California has experienced unusual seismicity and ground deformation since 1978, highlighted by four M>6 earthquakes in May 1980 and by the discovery soon thereafter of a broad uplift within Long Valley caldera. Recurrent seismic swarms during June 1980-May 1982 raised concern over the possibility of renewed volcanic activity in the foreseeable future, prompt
Authors
Daniel Dzurisin, K. V. Cashman, D. A. Johnston, Arthur G. Sylvester

Chemistry and isotope ratios of sulfur in basalts and volcanic gases at Kilauea volcano, Hawaii

Eighteen basalts and some volcanic gases from the submarine and subaerial parts of Kilauea volcano were analyzed for the concentration and isotope ratios of sulfur. By means of a newly developed technique, sulfide and sulfate sulfur in the basalts were separately but simultaneously determined. The submarine basalt has 700 ± 100 ppm total sulfur with δ34SΣs of ‰0.7 ± 0.1 ‰. The sulfate/sulfide mola
Authors
H. Sakai, T. J. Casadevall, J. G. Moore

Geodetic measurement of crustal deformation on the San Andreas, Hayward, and Calaveras faults near San Francisco, California

Analysis of a geodetic network of 115 lines crossing the San Andreas, Hayward, and Calaveras faults in the vicinity of San Francisco Bay and measured repeatedly between 1970 and 1980 has revealed details about the accommodation of relative plate motion in this area. The most striking result is that the deformation is not uniformly distributed across the area. In the east bay, along the Hayward and
Authors
W. H. Prescott, Michael Lisowski, James C. Savage

Overview of Mount St. Helens volcanic eruption

Dormant since 1857, Mount St. Helens Volcano in southwestern Washington stirred from its repose to erupt on March 27, 1980, following a week of premonitory earthquake activity. The eruption was the first in the conterminous United States since the 1914-1921 activity of Lassen Peak, California. The eruptive activity through May 17 was intermittent and relatively mild, but the accompanying seismic a
Authors
Robert I. Tilling

Pacific Coast coccolith stratigraphy between Point Conception and Cabo Corrientes, Deep Sea Drilling Project Leg 63

DSDP Leg 63 recovered Neogene coccoliths from south of Point Conception, California (Site 467), to north of Cabo Corrientes, Mexico (Site 473), as part of a traverse exploring the sedimentary record of the California Current along the Pacific Coast. A combination of temperate and tropical zonations were used to date Leg 63 coccolith assemblages because of intergradations of warm and cool species a
Authors
David Bukry

Silicoflagellate stratigraphy of offshore California and Baja California, Deep Sea Drilling Project, Leg 63.

Quantitative study of middle and upper Miocene silicoflagellate assemblages from Pacific Coast Sites 467 and 469 to 472 has permitted identification of warm- and temperate-water biostratigraphic zones and the formulation of a model for relative paleotemperature values (Ts) on the basis of warm- and temperate-genera abundances. Geographic and temporal trends in Ts for Pacific Coast assemblages are
Authors
David Bukry

Cenozoic coccoliths from the Deep Sea Drilling Project

Coccoliths, as the dominant constituent of many Deep Sea Drilling Project cores, have provided the means of rapid and detailed biostratigraphic zonation to help guide ocean-sediment coring operations aboard D.V. Glomar Challenger. The Cenozoic has been divided into 50 to 60 zones and subzones which are most effective for middle- and low- latitude sites. Because key stratigraphic coccoliths have pr
Authors
David Bukry

Synthesis of silicoflagellate stratigraphy for maestrichtian to quaternary marine sediment

Cosmopolitan and low-latitude silicoflagellate distributions determined from Deep Sea Drilling Project cores are synthesized into a sequence of 23 biostratigraphic zones and subzones for tropical and subtropical ocean areas. The stratigraphic relation of major morphologic changes in silicoflagellates from all areas is summarized. Two new Neogene subzones, one new Paleogene subzone, one new species
Authors
David Bukry