FAULTS AND EARTH TIDES

Geophysics ◽  
1961 ◽  
Vol 26 (5) ◽  
pp. 643-643
Author(s):  
Danilo A. Rigassi
Keyword(s):  
Geological Structure ◽  
Earth Tides ◽  
Geophysical Prospecting ◽  
Tidal Motion ◽  
The Earth ◽  
Two Sides

It can be assumed that the effect of luni‐solar attraction depends, to a certain extent, upon the geological structure. For instance, this effect should not be equal on the two sides of a fault separating rocks of different densities and competencies. If, on two geologically different blocks separated by a fault, two different values of the earth tidal motion can be measured, there is an earth tidal anomaly evidencing the presence of the fault. In other words, measuring and comparing earth tidal motions can be considered as a new geophysical prospecting method.

A Discussion on the measurement and interpretation of changes of strain in the Earth - Earth tides, ocean tides and tidal loading

1973 ◽  
Vol 274 (1239) ◽  
pp. 253-259 ◽  
Keyword(s):  
Potential Field ◽  
The Body ◽  
Earth Tides ◽  
Ocean Tide ◽  
Vertical Acceleration ◽  
Tidal Motion ◽  
The Earth ◽  
Almost Everywhere ◽  
Body Tides ◽  
Self Potential

The distortion of the Earth’s gravitational potential field by the A:f2 ocean tide has been calculated, accounting for both the elastic deformation of the Earth and the self potential of the water. The potential field generated by the ocean tide is almost everywhere greater than a tenth, and over much of the ocean is half as large as the lunar driving potential itself, and may have a significant influence on the tidal motion. Load tides in tilt, strain, and vertical acceleration also arise from the deformation of the Earth by the ocean tide. These load tides are probably of more geophysical and oceanographic interest than the body tides raised by the Sun and Moon.

ELECTRIC EARTH TRANSIENTS IN GEOPHYSICAL PROSPECTING

Geophysics ◽  
1936 ◽  
Vol 1 (2) ◽  
pp. 271-277 ◽  
Author(s):  
Louis Statham
Keyword(s):  
Electric Current ◽  
Salt Dome ◽  
Geophysical Prospecting ◽  
The Earth ◽  
Electrical Methods ◽  
The Times

A suddenly applied electric current is passed through the earth by means of spaced electrodes. The form of the potential transient as it appears outside the current electrodes is studied. The potential transient is extremely rapid and refined methods of recording are necessary. Means for measuring the relative times of the transient potentials received from different points are discussed. A survey taken over a known deep salt dome is shown; anomalous times of the transients are found to exist over the dome. No correlation is seen between the times of the transients and the resistivity as found by ordinary electrical methods.

Fundamental statistical techniques for the analysis of earth tides

1971 ◽  
Vol 61 (1) ◽  
pp. 203-215
Author(s):  
Cheh Pan
Keyword(s):  
Computer Technology ◽  
Earth Tide ◽  
Power Spectra ◽  
Correlation Coefficients ◽  
Earth Tides ◽  
Statistical Techniques ◽  
The Earth ◽  
Tidal Data ◽  
Instrumental Drift ◽  
Phase Differences

abstract Recent advances in instrumentation, digital computer technology and mathematical theory promote the error analysis of Earth-tide data. Various statistical techniques developed and used in other fields are applicable in the study of Earth tides, and the accuracy of the Earth's rigidity constants determined from the tides will be greatly improved with the help of these techniques. The fundamentals of the statistical techniques of autocorrelation, crosscorrelation, convolution, statistical means, bandpass filtering, correlation coefficients, power spectra, coherency and equalization are described, and their principal applications in the Earth-tide analysis summarized. Examples of effective application of these techniques in the elimination of the errors in the tidal data such as those introduced from instrumental drift, phase differences between the observed and predicted tides, etc. are discussed. This work is an attempt to introduce statistical analysis into the Earth-tide study.

scholarly journals On Investigations of the Tidal Waves Mf and Mm

1979 ◽  
Vol 82 ◽  
pp. 315-316
Author(s):  
G. P. Pil'nik
Keyword(s):  
Solid Earth ◽  
Elastic Properties ◽  
Earth Tides ◽  
Love Number ◽  
Astronomical Observations ◽  
Tidal Waves ◽  
The Earth ◽  
Astronomical Time ◽  
Solid Earth Tides

The comparison of astronomical time observations with the theory of solid-Earth tides makes it possible to determine the Love number, k, which characterizes the elastic properties of the Earth. In addition, the comparison of values of k determined from different tidal waves allows us to judge the accuracy of the nutational theory in astronomical observations since both tides and the Earth's nutation are produced by the same causes.

scholarly journals On the link between Earth tides and volcanic degassing

2019 ◽  
Author(s):  
Florian Dinger ◽  
Stefan Bredemeyer ◽  
Santiago Arellano ◽  
Nicole Bobrowski ◽  
Ulrich Platt ◽  
...  
Keyword(s):  
Quantitative Model ◽  
Earth Tides ◽  
Bubble Coalescence ◽  
Magmatic System ◽  
Volcanic Emissions ◽  
Volcanic Gas ◽  
Tidal Variation ◽  
Magma Flow ◽  
Volcanic Degassing ◽  
The Earth

Abstract. Long-term measurements of volcanic gas emissions conducted during the recent decade suggest that under certain conditions the magnitude or chemical composition of volcanic emissions exhibits periodic variations with a period of about two weeks. A possible cause of such a periodicity can be attributed to the Earth tidal potential. The phenomenology of such a link has been debated for long, but no quantitative model has yet been proposed. The aim of this paper is to elucidate whether a causal link from the tidal forcing to variation in the volcanic degassing can be traced analytically. We model the response of a simplified magmatic system to the local tidal gravity variations and derive a periodical vertical magma displacement in the conduit with an amplitude of 0.1–1 m, depending on geometry and physical state of the magmatic system. We find that while the tide-induced vertical magma displacement has presumably no significant direct effect on the volatile solubility, the differential magma flow across the radial conduit profile may result in a significant increase of the bubble coalescence rate in a depth of several kilometres by up to several ten percent. Because bubble coalescence facilitates separation of gas from magma and thus enhances volatile degassing, we argue that the derived tidal variation may propagate to a manifestation of varying volcanic degassing behaviour. The presented model provides a first basic framework which establishes an analytical understanding of the link between the Earth tides and volcanic degassing.

scholarly journals V.—Note on the Geographical Distribution of Volcanos

1880 ◽  
Vol 7 (4) ◽  
pp. 166-170
Author(s):  
J. Milne
Keyword(s):  
Geographical Distribution ◽  
Geological Structure ◽  
Primary Result ◽  
The Earth ◽  
Secondary Results

From what we know about the cooling of the earth and its geological structure, it would seem very probable that the principal features which we now see upon the surface of our planet, as, for instance, the continents and ocean-beds, received their forms in very early times, being, in fact, more or less a primary result of contraction. Since the formation of these impressions, contractions have continued to take place, and secondary results have come about, the character of which would appear in a great measure to be dependent upon the primary results by which they were preceded. Amongst the secondary results I would point to the position occupied by many volcanos.

A Pump-Probe Analysis of Nonlinear Elastic Behavior on the San Andreas Fault

2020 ◽  
Author(s):  
Andrew Delorey
Keyword(s):  
San Andreas Fault ◽  
Earth Tides ◽  
Elastic Behavior ◽  
Fracture Networks ◽  
Pump Probe ◽  
San Andreas ◽  
The Earth ◽  
Probe Analysis ◽  
Highly Nonlinear ◽  
Nonlinear Elastic

<p>Fracture networks in the subsurface influence nearly every aspect of earthquakes and natural hazards.  These aspects, including stress, permeability and material failure, and are important for hazard assessment. However, our ability to monitor fracture behavior in the Earth is insufficient for any type of decision-making regarding hazard avoidance.  I propose a new method for probing the evolution of fracture networks in situ to inform public safety decisions and understand natural systems. </p><p>In heterogeneous, fractured materials, like those found in the Earth, the relationship between stress and strain is highly nonlinear.  This nonlinearity in the upper crust is almost entirely due to fractures.  By measuring to what extent Earth materials exhibit nonlinear elastic behavior, we can learn more information about them.  Directly, measuring physical properties may be more useful than just detecting that fractures are present or how they are shaped and oriented.  We measure nonlinearity by measuring the apparent modulus at different strains. </p><p>In this study we use a pump-probe analysis, which involves continuously probing velocity (as a proxy for modulus) while systematically straining the material.  We will use solid Earth tides as a strain pump and empirical Green’s functions (EGF) as a velocity probe.  We apply this analysis to the San Andreas Fault near Parkfield, California.  We chose Parkfield because there is a long-term deployment of borehole seismic instruments that recorded before and after a M6 earthquake.  We find evidence that nonlinear behavior is correlated with the seismic cycle and therefore it may contain information on the both the evolution and current state of stress on faults. </p>

On: RIGASSI’S NOTE ON “FAULTS AND EARTH TIDES,” (GEOPHYSICS, OCTOBER, 1961, P. 643).

Geophysics ◽  
1962 ◽  
Vol 27 (2) ◽  
pp. 276-276
Author(s):  
M. F. Gillett
Keyword(s):  
Earth Tides ◽  
Geophysical Prospecting ◽  
Gravity Variations ◽  
Made In

The comments that Mr. Rigassi made in his discussion of Faults and Earth Tides are significant and suggest an extensive examination of earth tides or gravity variations (with time) as related to geophysical prospecting. Mr. Rigassi should be complimented for making and reporting his experiment.

Sign in / Sign up

Export Citation Format

Share Document