摘要:

Microseismic data obtained by the Naval Aerological Service from its ten seismograph stations show that severe wind storms over water cause large sections of the Earth's crust to vibrate. These oscillations are called microseisms and have been recorded on sensitive seismographs up to 1600 mi from the source. The direction of propagation of certain dominant microseisms, especially those produced by hurricanes and typhoons, can be determined with great accuracy when they pass over a tripartite seismograph station. The microseismic method of storm detection as outlined in this paper is being developed by the Naval Aerological Service and is now used to supplement other methods of detecting and forecasting severe storms.

ISSN:0002-8606    

DOI:10.1029/TR030i002p00165-2

年代:1949

数据来源: WILEY

摘要:

In order to determine the origin and nature of the Earth's magnetic field and to test the various hypotheses which have been advanced to explain the field, it is desirable to determine the history of this field throughout geologic time and to investigate more carefully its spatial variations but inside and outside the Earth's surface. The research described was concerned with the determination of the history of the Earth's field as it can be reduced from the present polarization of crust material. Unconsolidated fresh‐ and salt‐water sediments have been investiga

ISSN:0002-8606    

DOI:10.1029/TR030i002p00169-2

年代:1949

数据来源: WILEY

摘要:

AtlantisCruise 150, sponsored by the National Geographic Society, Columbia University, and the Woods Hole Oceanographic Institution, was a two month trip to Bermuda, the Azores the Mid‐Atlantic Ridge in the summer of 1947. A continuous record of depth beneath the ship along the track gave significant topographic information and provided a valuable guide to the choice of locations for measurements of other types.Thirty‐five sediment cores were taken with the Stetson‐Hvorslev apparatus, about a ton of rocks were dredged up, and several excellent seismic refraction records were obtained at various stations. Seismic reflection measurements were made at intervals of about ten miles along most of the track and some work was done on photography of the ocean floor. Hydrographic and biological observations were made, including a number of hauls with the Blake

ISSN:0002-8606    

DOI:10.1029/TR030i002p00170

年代:1949

数据来源: WILEY

摘要:

It appears that the effects on the Earth's thermal history of the exponential decay of the sources of atomic (radioactive) heat within the Earth are such that the upper crust of the Earth was heating in its early history and that subsequent cooling has been more nearly linear than has been supposed. In the deeper parts of the crust and below, the thermal history has been complex with simultaneous heating at one depth and cooling at another depth. Temperatures in the past beneath a Pacific‐type ocean have not varied in the same manner.Recent determinations of the radioactivity of ultrabasic rocks and iron meteorites are such that a monomineralic olivine mantle and an iron core will have remained essentially at the initial temperatures.The Earth, now presumably differentiated, may have had an earlier existence as an undifferentiated body formed by the coalescence of particles. Its rebirth as a molten, differentiated, and later frozen body is possible if the total radioactive content of the Earth was previously distributed uniformly and if its dust‐cloud origin dates back about seven billion years. A parental planet from which might have come the asteroids and meteorites may have disrupted because of stresses accumulated by internal heat

ISSN:0002-8606    

DOI:10.1029/TR030i002p00171-2

年代:1949

数据来源: WILEY

摘要:

The upper layers of the Earth's crust are represented in the sea by the sediments which are being deposited from a variety of sources and at a rate which varies from place to place and from time to time. A relatively complete series of sediments should be found in deep‐sea deposits if we assume that the present ocean basins have remained approximately as they are now throughout a major part of geologic time. In this discussion the term, deep‐sea sediments, is used in a very broad sense but generally to include those deposits which occur on the floors of the large ccean basins below about 2000 fathoms water de

ISSN:0002-8606    

DOI:10.1029/TR030i002p00180

年代:1949

数据来源: WILEY

摘要:

Pollen analysis has been extensively used in Europe not only in studies of postglacial climatic fluctuations, but also in conjunction with investigations of eustatic changes in sea level and isostatc land movements. A beginning in this field of research has been made in several sections of the United States.

ISSN:0002-8606    

DOI:10.1029/TR030i002p00182

年代:1949

数据来源: WILEY

摘要:

Thee daily rhythm of the tides is familiar to everyone who has lived or vacationed near tide‐water. The forces which produce the tides are due to the attraction of the Moon and the Sun. These same forces act over the land masses where their effects are less obvious and less well known. Formulas and tables are available from which the tide producing forces may be computed for any place and any moment of time. The forces so computed for any point on the Earth's surface over pay period of time would correspond to the variations with time of the acceleration of gravity at that point, if the Earth were unyielding. The actually observable variations will depart from those computed because the Earth yields in response to the tide‐producing for

ISSN:0002-8606    

DOI:10.1029/TR030i002p00183

年代:1949

数据来源: WILEY

摘要:

In researches previously published [Ricker, 1940, 1941, 1943, 1944, 1945], the author fast shown theoretically that the disturbance created by the detonation of a small charge of explosive in a homogeneous and isotropic Earth assumes a certain characteristic form, shaped by the Eartr absorption spectrum for elastic waves. This form and its variants have been called seismic wave. According to the theory, when observed at a great distance from the explosion, the wavelet should assume a symmetrical form. Figure 1 shows the form of the displacement, and represent the motion of the trace of a mechanical seismograph as it would record the motion, the mechanics seismograph being properly designed so as to avoid distortion.

ISSN:0002-8606    

DOI:10.1029/TR030i002p00184

年代:1949

数据来源: WILEY

摘要:

Since 1939 a series of rockbursts have been occurring in the gold mines at Kirkiand Lake. These rockkbursts recommend themselves as a source of energy for the investigation of crystal structure, since the mechanism of energy release has been shown to be similar to that of earthquakes. A seismograph has been installed at Kirkland Lake to time the occurrence of the bursts and a series of seismograph stations has been installed along a traverse towards Ottawa. By changing the location of these stations as bursts are recorded, a refraction profile will be built up. While the program is in operation the stations serve also as additional stations of the Canadian chain.

ISSN:0002-8606    

DOI:10.1029/TR030i002p00186

年代:1949

数据来源: WILEY

摘要:

The physical properties of materials as tabulated in handbooks and as used in our everyday life refer to measurements made in the environment which surrounds us, namely at atmospheric pressure (slightly more than one bar at sea level).If we were able to move down into the interior of the Earth with our testing equipment we would find the environmental pressure increasing at a rate of about 30,000 bars for each 100 km of descent. We would find, moreover, that under these conditions our testing apparatus would record very different physical behavior from that which might be anticipated from observations made at the surface under our normal atmospheric environment.

ISSN:0002-8606    

DOI:10.1029/TR030i002p00187

年代:1949

数据来源: WILEY