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A C language implementation of the SRO (Murdock) detector/analyzer A C language implementation of the SRO (Murdock) detector/analyzer

A signal detector and analyzer algorithm was described by Murdock and Hutt in 1983. The algorithm emulates the performance of a human interpreter of seismograms. It estimates the signal onset, the direction of onset (positive or negative), the quality of these determinations, the period and amplitude of the signal, and the background noise at the time of the signal. The algorithm has...
Authors
James N. Murdock, Scott E. Halbert

Large-scale variation in lithospheric structure along and across the Kenya rift Large-scale variation in lithospheric structure along and across the Kenya rift

The Kenya rift is one of the classic examples of a continental rift zone: models for its evolution range from extension of the lithosphere by pure shear1, through extension by simple shear2, to diapiric upwelling of an asthenolith3. Following a pilot study in 19854, the present work involved the shooting of three seismic refraction and wide-angle reflection profiles along the axis...
Authors
C. Prodehl, J. Mechie, W. Kaminski, K. Fuchs, C. Grosse, H. Hoffmann, R. Stangl, R. Stellrecht, M.A. Khan, Peter K.H. Maguire, W. Kirk, Gordon R. Keller, A. Githui, M. Baker, Walter D. Mooney, E. Criley, J. Luetgert, B. Jacob, H. Thybo, M. Demartin, S. Scarascia, A. Hirn, J. R. Bowman, I. Nyambok, S. Gaciri, J. Patel, E. Dindi, D.H. Griffiths, R.F. King, A. E. Mussett, L.W. Braile, G. Thompson, K. Olsen, S. Harder, R. Vees, D. Gajewski, A. Schulte, J. Obel, F. Mwango, J. Mukinya, D. Riaroh

Geodetic estimate of coseismic slip during the 1989 Loma Prieta, California, Earthquake Geodetic estimate of coseismic slip during the 1989 Loma Prieta, California, Earthquake

Offsets in the relative positions of geodetic stations resulting from the Loma Prieta earthquake can be explained with a dislocation model that includes buried oblique slip on a rupture surface extending 37 km along the strike of the San Andreas fault, dipping 70° to the SW, and extending from a depth of about 5 to 17.5 km. Assuming uniform slip on a rectangular surface, the mean values...
Authors
Michael Lisowski, W.H. Prescott, James C. Savage, M. J. Johnson

A possible geodetic anomaly observed prior to the Loma Prieta, California, Earthquake A possible geodetic anomaly observed prior to the Loma Prieta, California, Earthquake

Monthly measurements since mid‐1981 of distance from a geodetic station located 11 km from the epicenter of the Loma Prieta earthquake (Ms = 7.1; October 17, 1989) to three stations 30 to 40 km distant provides an unusually complete record of deformation in the epicentral region in the years prior to an earthquake. Roughly 1.3 years before the earthquake, at about the time of the first...
Authors
Michael Lisowski, W.H. Prescott, James C. Savage, Jerry L. Svarc

An apparent shear zone trending north‐northwest across the Mojave Desert into Owens Valley, eastern California An apparent shear zone trending north‐northwest across the Mojave Desert into Owens Valley, eastern California

Strain rates measured at four geodetic networks in eastern California situated between northern Owens Valley and the Transverse Ranges along a small circle drawn about the Pacific‐North America pole of rotation are remarkably consistent. Each exhibits 0.14 μrad/yr simple right‐lateral engineering‐shear‐strain accumulation across the local vertical plane tangent to the small circle. Local...
Authors
James C. Savage, Michael Lisowski, W.H. Prescott

Liquefaction and foundation failure of Chevron oil and gasoline tanks at Moss Landing, California Liquefaction and foundation failure of Chevron oil and gasoline tanks at Moss Landing, California

Liquefaction of gray, coarse‐ to medium‐grained, esturine sand during the October 17, 1989 Loma Prieta (Ms=7.1) earthquake led to foundation failures of oil and tanks at the Chevron Marine Station at Moss Landing located about 25 km south‐southeast of the epicenter. Differential settlement of the foundations resulted in 1° to 6° of the tanks towards one another and an associated 2° to 7°
Authors
Martitia Tuttle, Patience Cowie, John Tinsley, Michael Benett, John Berrill

Preliminary velocity and resistivity models of the Loma Prieta Earthquake region Preliminary velocity and resistivity models of the Loma Prieta Earthquake region

A preliminary three-dimensional velocity model of the Loma Prieta epicentral region in the Santa Cruz Mountains of California has been derived using raypaths from aftershocks recorded by the U.S.G.S. seismic network. In addition, a magnetotelluric sounding profile was completed prior to the earthquake and a two-dimensional resistivity model computed. The velocity and resistivity models...
Authors
Donna Eberhart-Phillips, Victor F. Labson, William D. Stanley, Andrew J. Michael, Brian D. Rodriguez

Ground motion Ground motion

No abstract available.
Authors
Roger D. Borcherdt, N. C. Donovan, Mehmet Celebi, A. Shakal, M. Huang, M. Reichle, C. Ventura, T. Cao, R. Bherburne, M. Savage, Robert B. Darragh, C. Petersen, David Boore, W. B. Joyner, E. V. Leyendecker, P.C. Thenhaus, Kimberly W. Campo, Margaret G. Hopper, S.L. Hanson, S. T. Algermissen, David M. Perkins, Susan E. Hough, D. Simpson, A. Lerner-Lam, P.A. Friberg, R. Busby, L. Shengold, M. Tuttle, Edward H. Field, K.H. Jacob, J. Pacheco, C. Estabrook, M. Peterson, Douglas H. Johnson, Arthur D. Frankel

Basal slip and mechanical anisotropy of biotite Basal slip and mechanical anisotropy of biotite

The basal slip systems of biotite and their mechanical expressions have been investigated by shortening single crystals oriented to maximize and minimize shear stresses on (001). Samples loaded at 45° to (001) exhibit gentle external rotations associated with dislocation glide. High‐angle kink bands in these samples, unlike those developed in micas loaded parallel to (001), are limited...
Authors
A. K. Kronenberg, Stephen H. Kirby, John C. Pinkston

The San Andreas Fault System, California The San Andreas Fault System, California

Maps of northern and southern California printed on flyleaf inside front cover and on adjacent pages show faults that have had displacement within the past 2 million years. Those that have had displacement within historical time are shown in red. Bands of red tint emphasize zones of historical displacement; bands of orange tint emphasize major faults that have had Quaternary displacement...
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