摘要:

With the increasing number of surveys based on astronomical coordinates and with loran stations established on oceanic islands far from the mainland and its geodetic control, there has been an increasing interest in deflections of the vertical.Some of those who have a professional interest in deflections of the vertical but who have not analyzed the underlying conceptions seem to have the vague idea that there is something in nature that might properly be called the deflection of the vertical. In the present state of geodesy there is nothing that may properly be called the deflection of the vertical at a given point. All existing numerical values of the deflection depend on the assumed geodetic datum, and the geodetic datum might conceivably be anything whatever, though in practice the choice is confined within rather narrow limits.

ISSN:0002-8606    

DOI:10.1029/TR028i002p00153

年代:1947

数据来源: WILEY

摘要:

Relative gravity observations in the United States and international gravity ties have been referred to several base stations in Washington, D.C. Correlation of these data has been based on gravity differences between the base stations determined by pendulum observations, some of which date back to 1893. The results of recent gravitational ties between the principal gravity base stations in Washington, D.C., using a modern high‐precision gravimeter are reported and discussed. The gravimeter results indicate that the previous pendulum connections between the base stations in Washington contain errors of about 2 m

ISSN:0002-8606    

DOI:10.1029/TR028i002p00157

年代:1947

数据来源: WILEY

摘要:

Because of the possibility of using seismic equipment in the location of coastal outlines beneath the surface of the Antarctic ice, and for the purpose of making a detailed study of the little understood Ross Shelf Ice, a specially designed seismograph was included in the scientific equipment of the Byrd Antarctic Expedition II, 1933–1935, One hundred and twenty‐two stations were occupied in the general area of the Bay of Whales from which it was possible to determine the thickness of the ice, tell whether it was floating or resting on the bottom, and if floating, what the depth of the water was, and something about the stratification of the bot

ISSN:0002-8606    

DOI:10.1029/TR028i002p00162

年代:1947

数据来源: WILEY

摘要:

Simple equipment for totalizing the number of static discharges through a neon glow tube or similar intermittent illuminations is here outlined, with salient constructional features.

ISSN:0002-8606    

DOI:10.1029/TR028i002p00171

年代:1947

数据来源: WILEY

摘要:

The Los Angeles area is faced with the problem of planning the mitigation of air pollution. The meteorological factors which determine the distribution of the pollution and the intensity of the nuisance are the height of the prevailing summer subsidence inversion and the local sea‐land breeze regime. Data on details of the wind structure and visibility are presented. These, with the time variations of the inversion, are discussed in relation to the pollution proble

ISSN:0002-8606    

DOI:10.1029/TR028i002p00173

年代:1947

数据来源: WILEY

摘要:

Magnetic measurements for geophysical work have been largely confined to measurement of the vertical field. Recently an instrument that measures only the total magnetic field has been invented and used with considerable success. Its operation is simpler and faster than the vertical magnetometer and its accuracy is as good as the best of the available vertical instruments. Since the instrument responds only to the total field, its readings are completely independent of orientation or leveling. It is shown that the readings of this instrument give the component of the magnetic anomalies along the direction of dip of the Earth's field. Since this “slant” anomaly is not directly comparable with ordinary measurements of the vertical and horizontal anomalies, or easily interpretable, a method of computing the equivalent vertical and horizontal anomalies has been devised. It is shown that the horizontal and vertical anomalies can be expressed as surface integrals over the surface of measurement of the “slant” anomaly. Means of evaluating these integrals are di

ISSN:0002-8606    

DOI:10.1029/TR028i002p00193

年代:1947

数据来源: WILEY

摘要:

An expression is derived from very general assumptions for the increase in wave period during long‐distance propagation. To illustrate the general nature of the solution, application is made to three different geophysical phenomena: First, to the tsunami from the Aleutian earthquake of April 1, 1946; second, to the long forerunners of the swell recorded at the wave station in Pendeen, England; and finally to the seismic surface waves from the Montana earthquake of June 28, 1925, and a smaller Mexican shock in 1943. In the case of the tsunami and the swell, observations and theory are in good agreement. For the seismic surface waves the theory gives at least the right order of magnitude. Application of the theory to the period increase of swell seems furthermore to provide a simple, rational basis for locating and tracking storms at sea by means of swell observations, and may therefore be of interest in weather forecastin

ISSN:0002-8606    

DOI:10.1029/TR028i002p00198

年代:1947

数据来源: WILEY

摘要:

Chromite deposits In the Moa district, on the north coast of Oriente Province, Cuba, form one facies of the ultramafic complex in which they occur. Two planar structures, one a compositional layering due to variations in the relative proportions of olivine, pyroxene, plagioclase feldspar, and chromite, and the other a foliation caused by the orientation of pyroxene crystals in peridotite, are in general parallel, but diverge in a few places. Dips are fairly constant, being moderate to the northwest over most of the area, but sharp reversals occur immediately adjacent to irregularities in the chromite deposits. Two prominent joint sets are present: (1) Cross joints striking parallel to the strike of the foliation and dipping approximately at right angles to it; and (2) longitudinal joints striking parallel to the direction of dip of the foliation and nearly vertical. Gabbro dikes follow the first set, chrysotlle veins the second. Within the ore bodies dikes are commonly coarser‐grained, larger, and far more abundant than in peridotite; they enclose coarse, angular fragments of chromit

ISSN:0002-8606    

DOI:10.1029/TR028i002p00218

年代:1947

数据来源: WILEY

摘要:

In recent years the problem of flood routing has received a great share of attention. In design of flood‐control works or river and harbor improvements the engineer is often called upon to determine the effects of natural valley storage, reservoirs, and navigation projects on flood flows and stages. Many methods and procedures have been developed for the purpose of facilitating and simplifying the calculations for the flood‐routing problems. Elaborate flood‐routing machines and linear and circular slide rules have been devised. However, the flood‐routing machines have not proven popular owing to their high cost of construction. The slide rule has the disadvantage that a different set of scales is required for each relation between discharge and storage, and it is not readily adaptable to change of time i

ISSN:0002-8606    

DOI:10.1029/TR028i002p00247

年代:1947

数据来源: WILEY

摘要:

Six types of macroturbulence phenomena in natural streams are discussed: Velocity and stage surges which are rhythmic or cyclic; eddying which is continuous; upward and downward vortex actions which are intermittent; transverse oscillations of water surface and helicoidal effects, which are continuous. These are all caused by channel roughness but do not appear to be related to microturbulence. However, the eddy and vortex types, which are flow separations, dissipate through disintegration at their peripheries into macroturbulence. A new term, “kolk,” is introduced to supplement a deficiency for designating upward vortex action, considered one of the most prolific as well as important forms of stream dynamics. The need for additional research is emphasi

ISSN:0002-8606    

DOI:10.1029/TR028i002p00255

年代:1947

数据来源: WILEY