Publications
Filter Total Items: 7243
More on the alleged 1970 geomagnetic jerk
French and United Kingdom workers have published reports describing a sudden change in the secular acceleration, called an impulse or a jerk, which took place around 1970. They claim that this change took place in a period of a year or two and that the sources of the alleged jerk are internal. An earlier paper by this author questioned their method of analysis pointing out that their method of pie
Authors
L.R. Alldredge
Steens Mountain geomagnetic polarity transition is a single phenomenon
[No abstract available]
Authors
C. S. Grommé, E. A. Mankinen, M. Prevot, R. S. Coe
High-frequency observations and source parameters of microearthquakes recorded at hard-rock sites
We have estimated the source parameters of 53 microearthquakes recorded in July 1983 which were aftershocks of the Miramichi, New Brunswick, earthquake that occurred on 9 January 1982. These events were recorded by local three-component digital seismographs at 400 sps/component from 2-Hz velocity transducers sited directly on glacially scoured crystalline basement outcrop. Hypocentral distances ar
Authors
Edward Cranswick, Robert Wetmiller, John Boatwright
How the geomagnetic field vector reverses polarity
A highly detailed record of both the direction and intensity of the Earth's magnetic field as it reverses has been obtained from a Miocene volcanic sequence. The transitional field is low in intensity and is typically non-axisymmetric. Geomagnetic impulses corresponding to astonishingly high rates of change of the field sometimes occur, suggesting that liquid velocity within the Earth's core incre
Authors
M. Prevot, E. A. Mankinen, C. S. Grommé, R. S. Coe
Saudi Arabian seismic-refraction profile: A traveltime interpretation of crustal and upper mantle structure
The crustal and upper mantle compressional-wave velocity structure across the southwestern Arabian Shield has been investigated by a 1000-km-long seismic refraction profile. The profile begins in Mesozoic cover rocks near Riyadh on the Arabian Platform, trends southwesterly across three major Precambrian tectonic provinces, traverses Cenozoic rocks of the coastal plain near Jizan, and terminates a
Authors
Walter D. Mooney, M. E. Gettings, H. R. Blank, J. H. Healy
Geographic variation in ground shaking as a function of changes in near-surface properties and geologic structure near Los Angeles, California
No abstract available.
Authors
A. M. Rogers, Ladislaus C. Tinsley, Roger D. Borcherdt
Innovative approaches to landslide hazard and risk mapping
No abstract available.
Authors
E. E. Brabb
Deformation in the White Mountain seismic gap, California-Nevada, 1972-1982
A 100×40 km trilateration network extending from Bishop, California, to near Hawthorne, Nevada, crosses the east end of the Long Valley caldera, site of renewed magma inflation in the 1979–1980 interval, and spans most of the White Mountain seismic gap. The network was surveyed in 1972, 1973, 1976, 1979, 1980, and 1982. The 1980 survey may be contaminated by a scale error. In addition, leveling su
Authors
James C. Savage, Michael Lisowski
Earthquake swarm in Long Valley caldera, California, January 1983: Evidence for dike inflation
The 1982–1983 deformation observed by trilateration and leveling surveys across the Long Valley caldera is apparently related to the 8.5‐km‐long by 8‐km‐deep vertical rupture surface defined by the January 1983 earthquake swarm that occurred in the south moat of the caldera. The observed deformation can be explained as follows. In late 1982, 0.03 km3 of magma was injected into a dike that dips 30°
Authors
James C. Savage, R.S. Cockerham
Regional deformation near Palmdale, California, 1973-1983 (USA)
The Tehachapi trilateration network spans the intersection of the San Andreas and Garlock faults in southern California in the “Big Bend” region of the San Andreas fault. Analysis of data from 1973–1983 shows strain differences between the northwest and southeast regions of the network and slip at depth on both faults. The Palmdale network, spanning the San Andreas fault entirely within the Tehach
Authors
N.E. King, James C. Savage
A comparative ground response study near Los Angeles using recordings of Nevada nuclear tests and the 1971 San Fernando earthquake
A comparative ground response study at sites in the Los Angeles region is based on the extensive strong-motion data set recorded in the 1971 San Fernando earthquake and 159 three-component recordings of distant nuclear tests in Nevada. Amplitude spectral ratios computed for the nuclear test data over those frequency bands for which there is an adequate signal-to-noise ratio provide statistically s
Authors
A. M. Rogers, Roger D. Borcherdt, P. A. Covington, D. M. Perkins
On recent advances in strong-motion data acquisition capabilities
No abstract available.
Authors
Roger D. Borcherdt