摘要:

The American Geophysical Union is the American National Committee of the International Union of Geodesy and Geophysics, and the Executive Committee of the American Geophysical Union is the Committee on Geophysics of the National Research Council. The objects of the Union are to promote the study of problems concerned with the figure and physics of the Earth, to initiate and coordinate researches which depend upon international and national cooperation, and to provide for their scientific discussion and publication. In the accomplishment of these objects, the Union is divided into sections following the plan of organization of the International Union of Geodesy and Geophysics. There are now seven sections, namely, (a) Geodesy, (b) Seismology, (c) Meteorology, (d) Terrestrial Magnetism and Electricity, (e) Oceanography, (f) Volcanology, and (g) Hydrology. A Section of Geophysical Chemistry was discontinued May 51, 1924, as the International Union had failed to provide such a Section; the Section of Hydrology was established November 15, 1930—matters pertaining to scientific hydrology referred to the American Geophysical Union had been previously looked after by special committees on hydrolog

ISSN:0002-8606    

DOI:10.1029/TR014i001p00003

年代:1933

数据来源: WILEY

摘要:

The Committee on Geophysical and Geological Study of Oceanic Basins was appointed at the last annual meeting of the American Geophysical Union, April 21 and 28, 1932, for the purpose of promoting, and aiding in every possible way, the study of structural and stratigraphic problems relating to oceanic basins, continental margins, and oceanic islands, especially those forming island‐arcs. This Committee isprimarilyconcerned, therefore, with oceanographic problems such as are of paramount interest both to geologists and to those geophysicists whose methods, formulas, apparatus, and techniques are particularly susceptible of adaptation, with or without modification, to an attack upon marine structural and stratigraphic problems. Some of the scientific problems faced by this Committee necessarily border on, or are directly connected with, problems which are of especial interest to the marine biologist and the oceanographer. Thus data concerning the temperature and salinity of sea‐water, currents, tides, marine sedimentation, and ecology, together with such phases of oceanography and oceanology as have a bearing on the subject of paleo‐geography and paleo‐oceanology, are also of direct importance to the stratigrapher and structural ge

ISSN:0002-8606    

DOI:10.1029/TR014i001p00009

年代:1933

数据来源: WILEY

摘要:

An areally extensive gravity‐minimum of considerable amplitude lies axially along the Gulf Coast. Three alternative explanations of its cause were suggested by the senior writer a year ago (D. C. Barton, Torsion‐balance surveys in Southwest Louisiana and Southeast Texas, Trans. Amer. Geophys. Union, 13th annual meeting, 40–42, 1932):(A) A geosyncline on the surface of a basement homogeneous in character from the center of the Gulf of Mexico to the center of the continent.(B) A gulfward regional dip of the surface of the basement in the Gulf Coast area plus a progressive change in the character of the basement from a granitic composition under the continent to a basaltic composition in the center of the Gulf of Mexico.(C) A geosyncline plus that progressive change in the character of the basement.(D) A fourth explanation, that it is wholly a salt‐effect, was suggested but now seems imp

ISSN:0002-8606    

DOI:10.1029/TR014i001p00016

年代:1933

数据来源: WILEY

摘要:

The relation of seismology to the study of the island‐arcs is nowhere better illustrated than in the West Indies Region. The study should include the northern part of South America and part of Mexico. The peculiar significance of the Caribbean Sea with little activity in its central basin completely surrounded by regions of earthquake‐activity presents a problem which is duplicated only in the region to the east of a line joining Japan and the Philippine Islands.The special problems of the region include: The geological significance of the closed loop and especially the geological conditions in Central America and Ecuador and Colombia where the two parts of the loop separate; the significance of earthquake‐activity in the Bartlett Deep and also in the Nares Deep; the relation of the seismic activity to the as yet inadequately known submarine contours in the Windward Islands Region and the relation of seismic and volcanic activity in the same region. Others might be added, but these suffice to give the type of pro

ISSN:0002-8606    

DOI:10.1029/TR014i001p00020

年代:1933

数据来源: WILEY

摘要:

In connection with the problems coming before the Committee on Geophysical and Geological Study of Oceanic Basins, the systematic and continuous observation of tides at a number of places is of importance in two directions. In the first place, such tide‐observations permit the accurate determination of basic datums from which both heights on land and depths in the sea may be measured. And, in the second place, such observations furnish quantitative data for determining coastal stability.Sea‐level is the universal datum to which heights on land and depths in the sea are referred. This universal use of sea‐level as a datum‐plane is due to a number of advantages it possesses. It is a rational datum‐plane and one that everywhere has the same definition; it is, too, a familiar term, and one that is self‐explanatory. The geophysicist has adopted the term, and by prefixing the word “mean” has sought to give it a more precise meaning. The expression “mean sea‐level” is apparently free from ambiguity and carries an implication that can be determined readily and accurately. However, when it becomes necessary to determine this plane accurately, difficulties appear. For we find that sea‐level at any point along the coast varies from day to day, from month to month

ISSN:0002-8606    

DOI:10.1029/TR014i001p00021

年代:1933

数据来源: WILEY

摘要:

Hydrology has a more or less intimate relation to all the geophysical sciences. There are other sciences which are terrestrial, although not counted as geophysical, where the interrelations with hydrology are especially marked. I refer in particular to the biological sciences. Direct interrelations of animal life to hydrology are not wanting. Examples are furnished by the relation of the migration of fishes to freshwater floods of streams and by the life‐habits of many oysters, which seek the transition‐zone between salt and fresh water for elements vital to their existence and for protection from their enemies, and suffer if the ordinary course of the hydrological cycle is disturbed. Darwin directed attention to the agronomic importance of earthworms, but it remained for Lawes, Gilbert, and Warington (The amount and composition of drainage‐waters collected at Rothamsted, J. R. Agr. Soc. Eng., v. 27, 275, 1881) fifty years ago to point out that in some of the best agricultural soils earthworm perforations apparently provide the principal means of entrance of rain‐water to and escape of air from the soil, thus permitting the underground phase of the hydrological cycle to be enacted and moisture‐supply for vegetation

ISSN:0002-8606    

DOI:10.1029/TR014i001p00023

年代:1933

数据来源: WILEY

摘要:

As the sections of Hydrology and Meteorology in the Geophysical Union are organized and the respective fields of activity are defined, the interrelation of interests of the two sections is so obvious as to appear to render discussion unnecessary. Their fields added to that of oceanography cover that never‐ending cycle of motion of water wherein it condenses in clouds, is precipitated as rain or snow, flows over and through the Earth's crust, accumulates largely in oceans, is taken into the air again by evaporation and transpiration, and is again condensed into clouds and precipitated. The Section of Hydrology works within that portion of this cycle that is represented approximately by the passage of water over and through the Earth's crust, the Section of Meteorology works within that portion represented approximately by the passage of water through the atmosphere, and the Section of Oceanography works within that portion represented by the oceans. Each field of activity begins, therefore, where another ends, and the work of one section is related to and must be consistent with the work of each of the others. The obvious points of contact between the sections of Hydrology and Meteorology are in those phases that relate to the transfer of water from the atmosphere to the Earth's crust (precipitation) and to the reverse action of transfer from the Earth's crust to the atmosphere (evaporation

ISSN:0002-8606    

DOI:10.1029/TR014i001p00025

年代:1933

数据来源: WILEY

摘要:

This paper is a very brief summary of a special bulletin on the climate of the Cumberland and Tennessee basins, now being published by the Weather Bureau.The Cumberland and Tennessee basins lie between longitudes 81° 30′ and 88° 30′ In a general way they form a rough quadrilateral, with its greatest length about 400 miles from east to west. Also, they may be likened to concentric arcs, the Tennessee being the outer and southerly one, with a total area of 40,667 square miles. The Cumberland is much smaller; its total area is 17,880 square miles. Combined they are 29 percent of the area of the entire Ohio

ISSN:0002-8606    

DOI:10.1029/TR014i001p00027

年代:1933

数据来源: WILEY

摘要:

To consider the relation of glaciation to other branches of geophysics we must first develop the cause of glaciation; and this will require us to recall some ideas which, though elementary, are fundamental, and it is by keeping fundamental principles in mind that we can build most securely the superstructure.The first requisite for glaciation is the excess of the annual snowfall in a more or less limited region over the melting and dissipation. A mass of snow is thus accumulated which grows in thickness, is gradually converted into ice, and slowly flows away into a region where not only Is the annual snowfall all melted but also the ice which has flowed into it.

ISSN:0002-8606    

DOI:10.1029/TR014i001p00028

年代:1933

数据来源: WILEY

摘要:

In many areas along the sea‐coasts of the world the water‐supply for human use is derived largely, and in some areas wholly, from underground sources. Because of the proximity to the ocean in these areas, in some respects the geologic and hydrologic conditions that govern the occurrence and movement of ground‐water are quite different from those in inland areas, and to properly interpret them the ground‐water hydrologist must avail himself of facts developed by the oceanographer.These conditions are encountered in a marginal zone that in different localities may extend only a few feet or many miles inland from the coast, and presumably for greater or less distances out beneath the ocean. These special conditions have been recognized and extensively studied for many years, for example, in the lowland‐area of Holland that lies between the Zuider Zee and the North Sea, and on Long Island, New York. Within recent years more or less attention has been given to these conditions in many of the coastal states of the United States, and in the Hawaiian Islands and Cuba. It is the purpose of this statement to indicate some of the problems of groundwater hydrology that are related to oce

ISSN:0002-8606    

DOI:10.1029/TR014i001p00030

年代:1933

数据来源: WILEY