New trend- trigonometric model for interpolation and prediction of the geomagnetic field utilizing the new DGRF models
L.R. Alldredge
1988, Journal of Geomagnetism & Geoelectricity (40) 749-759
At the IUGG Assembly at Vancouver during August 1987 new definitive geomagnetic reference field (DGRF) models to degree 10 for 1945, 1950, 1955, and 1960 were adopted by IAGA. Before these new DGRF models were accepted, the author developed a trend and trigonometric model (old trig model) based on the...
Response of well aquifer systems to Earth tides: Problem revisited
Paul A. Hsieh, John D. Bredehoeft, Stuart Rojstaczer
1988, Water Resources Research (24) 468-472
Two recent works cause us to reexamine Bredehoeft's (1967) analysis of earthtide response of water wells. Narasimhan et al. (1984) raise several questions regarding Bredehoeft's (1967) analysis and suggest that the analysis is internally inconsistent. They argue that one cannot directly estimate the specific storage, which characterizes the drained behavior...
Late Pleistocene drainage systems beneath Delaware Bay
H.J. Knebel, R.C. Circe
1988, Marine Geology (78) 285-302
Analyses of an extensive grid of seismic-reflection profiles, along with previously published sedimentary data and geologic information from surrounding coastal areas, outline the ancestral drainage systems of the Delaware River beneath lower Delaware Bay. Major paleovalleys within these systems have southeast trends, relief of 10-35 m, widths of 1-8 km,...
Further comments on sensitivities, parameter estimation, and sampling design in one-dimensional analysis of solute transport in porous media
Debra S. Knopman, Clifford I. Voss
1988, Water Resources Research (24) 225-238
Sensitivities of solute concentration to parameters associated with first-order chemical decay, boundary conditions, initial conditions, and multilayer transport are examined in one-dimensional analytical models of transient solute transport in porous media. A sensitivity is a change in solute concentration resulting from a change in a model parameter. Sensitivity analysis is...
Natural variance in pH as a complication in detecting acidification of lakes
J.T. Turk
1988, Water, Air, & Soil Pollution (37) 171-176
Natural variance in the pH of three dilute lakes in the Flat Tops Wilderness Area, Colorado, complicates the detection of acidification. Variations in pH during July-September of 1983 were: 0.95 (Ned Wilson Lake), 1.36 (Upper Island Lake), and 1.53 (Oyster Lake). Mean diurnal variations in pH during 1983 were: 0.37...
A magmatic model of Medicine Lake Volcano, California
J.M. Donnelly-Nolan
1988, Journal of Geophysical Research Solid Earth (93) 4412-4420
Medicine Lake volcano is a Pleistocene and Holocene shield volcano of the southern Cascade Range. It is located behind the main Cascade arc in an extensional tectonic setting where high-alumina basalt is the most commonly erupted lava. This basalt is parental to the higher-silica calc-alkaline and tholeiitic lavas that make...
Volcanic hazards and public response
D. W. Peterson
1988, Journal of Geophysical Research Solid Earth (93) 4161-4170
Although scientific understanding of volcanoes is advancing, eruptions continue to take a substantial toll of life and property. Some of these losses could be reduced by better advance preparation, more effective flow of information between scientists and public officials, and better understanding of volcanic behavior by all segments of the...
The Argos seismic data message system
J.S. Derr, R.N. Hunter
1988, Bulletin of the Seismological Society of America (78) 1000-1005
A reliable, inexpensive method for sending limited daily seismic data messages from remote observatories to the National Earthquake Information Center has been developed for use with the Argos satellite system. Data messages are compressed on a microcomputer and passed automatically to a simple transmitter. About 4 hr later, the data...
Ferromanganese deposits from the Gulf of Alaska Seamount Province: Mineralogy, chemistry, and origin
R.A. Koski
1988, Canadian Journal of Earth Sciences (25) 116-133
Ferromanganese-oxide deposits dredged from four seamounts (Welker, Miller, Murray, and Patton) in the Gulf of Alaska Seamount Province include poorly crystallized microlaminated crusts on basalt substrate, well-crystallized Mn-oxide veins in epiclastic sedimentary rocks, and crystalline Mn-oxide layers and micronodules in phosphorite. The principal rock types dredged are alkali-basalt pillow fragments...
A New Species of Pulvinites (Mollusca: Bivalvia) from the Upper Paleocene Paspotansa Member of the Aquia Formation in Virginia
L. W. Ward, T.R. Waller
1988, Journal of Paleontology (62) 51-55
Pulvinites lawrencei n.sp. is described from the upper Paleocene (Landenian Stage) Paspotansa Member of the Aquia Formation in Stafford County, Virginia. This is the first report of a member of the pteriacean family Pulvinitidae in the Tertiary on either side of the Atlantic, the only other post-Mesozoic records of Pulvinites...
Resonance of a fluid-driven crack: Radiation properties and implications for the source of long-period events and harmonic tremor
B. Chouet
1988, Journal of Geophysical Research Solid Earth (93) 4375-4400
A dynamic source model is presented, in which a three-dimensional crack containing a viscous compressible fluid is excited into resonance by an impulsive pressure transient applied over a small area ΔS of the crack surface. The crack excitation depends critically on two dimensionless parameters called the crack stiffness, C = (b/μ)(L/d), and...
Deformation in the Yakataga seismic gap, Southern Alaska, 1980-1986
J.C. Savage, M. Lisowski
1988, Journal of Geophysical Research Solid Earth (93) 4731-4744
A 60-by-40-km trilateration network in the Yakataga seismic gap was surveyed in 1980, 1982, 1984, and 1986 with precise electro-optical distance-measuring equipment to measure strain accumulation. The overall deformation is roughly approximated by a 0.24±0.03 µstrain/yr N32°W±2.4° uniaxial contraction that is uniform in time. However, the spatial distribution of deformation...
Parkfield, California, liquefaction prediction (USA)
T.L. Holzer, M.J. Bennett, T. L. Youd, A.T.F. Chen
1988, Bulletin of the Seismological Society of America (78) 385-389
The primary purpose of this short note is to formally record the liquefaction prediction (Holzer et al., 1986) made in connection with this predicted earthquake. In addition, this note serves to alert the seismic engineering community to special instrumentation being installed at the prediction site. The instrumentation will consist of...
The seismic radiation from composite models of faulting
J. Boatwright
1988, Bulletin of the Seismological Society of America (78) 489-508
The failure of an asperity, i.e., the dynamic rupture of a small fault area with finite stress drop surrounded by a broken or weak fault area which has no stress drop but which slips after the asperity fails, is proposed as a model for the rupture process of a subevent...
Absence of strain accumulation in the Shumagin seismic gap, Alaska, 1980-1987
M. Lisowski, J.C. Savage, W.H. Prescott, W.K. Gross
1988, Journal of Geophysical Research Solid Earth (93) 7909-7922
Measurements of the deformation of a trilateration network in the Shumagin seismic gap in the interval 1980–1987 failed to detect any significant strain accumulation (observed extension rate in the direction of plate convergence 0.00±0.03 μstrain/yr). Dislocation models of the subduction process and measurements at a comparable network at a known...
Lateral fluid flow in a compacting sand-shale sequence: South Caspian basin
John D. Bredehoeft, R. D. Djevanshir, Kenneth Belitz
1988, American Association of Petroleum Geologists Bulletin (72) 416-424
The South Caspian basin contains both sands and shales that have pore-fluid pressures substantially in excess of hydrostatic fluid pressure. Pore-pressure data from the South Caspian basin demonstrate that large differences in excess hydraulic head exist between sand and shale. The data indicate that sands are acting as drains for...
Variation of depth to the brittle-ductile transition due to cooling of a midcrustal intrusion
M. E. Gettings
1988, Geophysical Research Letters (15) 213-216
The depth to the brittle-ductile transition in the crust is often defined by the intersection of a shear resistance relation in the brittle upper crust that increases linearly with depth and a power law relation for ductile flow in the lower crust that depends strongly on...
The northeastern Ohio earthquake of 31 January 1986: Was it induced?
C. Nicholson, E. Roeloffs, R. L. Wesson
1988, Bulletin of the Seismological Society of America (78) 188-217
On 31 January 1986, at 11:46 EST, an earthquake of mb = 5.0 occurred about 40 km east of Cleveland, Ohio, and about 17 km south of the Perry Nuclear Power Plant. The earthquake was felt over a broad area, including 11 states, the District of Columbia, and parts of...
Making maps with computers
S.C. Guptill, L.E. Starr
1988, American Scientist (76) 136-142
Soon after their introduction in the 1950s, digital computers were used for various phases of the mapping process, especially for trigonometric calculations of survey data and for orientation of aerial photographs on map manuscripts. In addition, computer-controlled plotters were used to draw simple outline maps. The process of collecting data...
Taolin Zn-Pb-fluorite deposit, People's Republic of China: An example of some problems in fluid inclusion research on mineral deposits
E. Roedder, K.W. Howard
1988, Journal of the Geological Society (145) 163-174
The large Taolin zinc–lead–fluorite deposit in the People’s Republic of China was discovered 28 years ago, but whether its genetic affiliation is Mississippi Valley-type, epithermal, or mesothermal has remained uncertain. Both the ore and gangue (cherty to coarse quartz, plus barite, chlorite and calcite) occur as open space filling in...
Determining baseline element composition of lichens. II. Hypogymnia enteromorpha and Usnea spp. at Redwood National Park, California
L. P. Gough, L. L. Jackson, J.A. Sacklin
1988, Water, Air, & Soil Pollution (38) 169-180
Hypogymnia enteromorpha and Usnea spp. were collected in the Little Bald Hills ultramafic region of Redwood National Park, California, to establish element-concentration norms. Baselines are presented for Ba, Ca, Cu, Mn, Ni, P, Sr, V, and Zn for both lichen species; for Li, Mg, and K for H. enteromorpha; and for Al, Ce, Cr,...
Geometry of the Juan de Fuca plate beneath Washington and northern Oregon from seismicity
C.S. Weaver, G.E. Baker
1988, Bulletin of the Seismological Society of America (78) 264-275
Earthquake hypocenters within the subducting Juan de Fuca plate beneath Washington and northern Oregon are interpreted as showing that the direction of plate dip changes from northeast beneath the Puget Sound region to east-southeast beneath southwestern Washington. The shallowest hypocenters within the Juan de Fuca plate are between 30- to...
The mechanics of ground deformation precursory to dome-building extrusions at Mount St. Helens 1981-1982
W.W. Chadwick Jr., R.J. Archuleta, D. A. Swanson
1988, Journal of Geophysical Research Solid Earth (93) 4351-4366
Detailed monitoring at Mount St. Helens since 1980 has enabled prediction of the intermittent eruptive activity (mostly dome growth) with unprecedented success. During 1981 and 1982, accelerating deformation of the crater floor around the vent (including radial cracks, thrust faults, and ground tilt) was the earliest indicator of impending activity....
A statistical method for estimating rates of soil development and ages of geologic deposits: A design for soil-chronosequence studies
P. Switzer, J.W. Harden, R. K. Mark
1988, Mathematical Geology (20) 49-61
A statistical method for estimating rates of soil development in a given region based on calibration from a series of dated soils is used to estimate ages of soils in the same region that are not dated directly. The method is designed specifically to account for sampling procedures and uncertainties...
The distribution, structure, and composition of freshwater ice deposits in Bolivian salt lakes
S. H. Hurlbert, Cecily C.Y. Chang
1988, Hydrobiologia (158) 271-299
Freshwater ice deposits are described from seven, high elevation (4117-4730 m), shallow (mean depth <30 cm), saline (10-103 g l-1) lakes in the southwestern corner of Bolivia. The ice deposits range to several hundred meters in length and to 7 m in height above the lake or playa surface. They...
