The optical anchor—A geophysical strainmeter

1982 ◽  
Vol 72 (5) ◽  
pp. 1707-1715
Author(s):  
Frand Wyatt ◽  
Kent Beckstrom ◽  
Jon Berger
Keyword(s):  
Shear Strain ◽  
Path Length ◽  
Michelson Interferometer ◽  
Horizontal Displacement ◽  
Earth’S Crust ◽  
Near Surface ◽  
Strain Measurements ◽  
Earth's Crust

abstract An instrument has been developed to monitor the horizontal displacement of near-surface monuments, so as to reduce the noise of observatory-based strain measurements. The device measures the shear strain in the upper 24 m of the earth's crust using an equal path length Michelson interferometer. The magnitude of the observations (∼50 μm) indicates that such measurements are needed to interpret the records produced by precision strainmeters.

scholarly journals Local seismicity alterations in the South Yakutia mining region due to the technogenic impact on its geological environment

2018 ◽  
Vol 56 ◽  
pp. 04019
Author(s):  
Nikolay Grib ◽  
Valery Imaev ◽  
Galina Grib ◽  
Lyudmila Imaeva ◽  
Igor Kolodeznikov
Keyword(s):  
Indirect Effects ◽  
Earth’S Crust ◽  
Seismic Events ◽  
Geological Environment ◽  
The South ◽  
Near Surface ◽  
Earthquake Energy ◽  
Technogenic Impact ◽  
Earth's Crust ◽  
The Impact

Impulse loads, arising due to the high natural seismicity of the South Yakutia region, exercise both direct and indirect effects on the upper part of the Earth's crust during industrial explosions. The direct effects result from nonlinear displacements caused by the blast wave and the subsequent formation of new disturbances. The indirect effects arise due to the activation of structural elements along geological contacts, leading to the emergence of technogenic seismicity foci. The foci of induced seismicity are either confined to the blast points, or located along the tectonic structures crossing quarry fields. The technogenic impact on the geological environment transforms the independent local seismic process, since explosions trigger a chain of local seismic events. The near-surface layers of the Earth's crust become activated in the area of dynamic influence of active faults. Under the influence of explosions, both the number of seismic events and the average level of released energy alter. Impulse loads on the geological environment lead to a spatial redistribution of the foci of low-energy (K <7) earthquakes. The main form of the geodynamic development of seismogenic faults is the movement of their sides in the form of mutual “slippage”. Seismic events are manifested only when the aforementioned form of deformation is impossible or difficult to develop, in other words, when the stress-state areas of the Earth's crust develop. Therefore, the shaking impact of blasts can be considered as a factor contributing to the predominance of aseismic forms of fault motion in the form of smooth slippage of their sides. In conclusion, the impact of industrial blasts can not only activate faults around the mining area, but also have an unloading effect on the foci of seismic hazard forming in the interior, i.e. the redistribution of earthquake energy in terms of reducing earthquake energy class.

Deformations of the near-surface part of the Earth's crust by seismologic and geodetic data obtained on Baikal geodynamic polygons

1992 ◽  
Vol 202 (2-4) ◽  
pp. 251-256 ◽  
Author(s):  
S.I. Kesselman ◽  
P.E. Kotliar ◽  
O.A. Kuchay ◽  
S.A. Tychkov ◽  
L.I. Serebriakova
Keyword(s):  
Geodetic Data ◽  
Earth’S Crust ◽  
Near Surface ◽  
Surface Part ◽  
Earth's Crust

scholarly journals ZONES OF RECENT ACTIVATION AND SCHEME OF THE EARTH CRUST PERMEABILITY OF UKRAINE

2021 ◽  
Vol 17 (1) ◽  
pp. 75-84
Author(s):  
V.V. Gordienko ◽  
L.Ya. Gordienko ◽  
J.A. Goncharova ◽  
V.M. Tarasov
Keyword(s):  
Surface Waters ◽  
Previous Analysis ◽  
Relevant Information ◽  
Earth’S Crust ◽  
Near Surface ◽  
The Past ◽  
The Earth ◽  
Continue Research ◽  
Earth's Crust ◽  
Background Gas

An attempt is considered to supplement the criteria for identifying zones of recent activation in the territory of Ukraine with another one — data on the results of studies of helium concentration in ground-water. The previous analysis of information showed that as regional criteria, information can be applied on anomalies in heat flow, increased electrical conductivity of Earth’s crustal and the upper mantle rocks, distribution of mantle gravitational anomalies, and surface uplifts over the past millions of years. They were chosen among others precisely because of the dissemination of relevant information throughout the country. This requirement is also met by the permeability Scheme of the earth’s crust of Ukraine, which is a fragment of the permeability Scheme of the earth’s crust of the European part of the USSR based on the results of helium studies. The principal applicability of such information for solving the problem is shown. Areas of maximum helium concentrations in near-surface waters are indicated, primarily those associated with disjunctive dislocation. Theу are concentrated in the south-west of Ukraine and in Moldova. The disadvantages of the Scheme are noted, due to poor study and significant variations in background gas concentrations, directly caused not by recent activation, but by the peculiarities of helium generation by rocks of the upper part of the earth’s crust. There are inconsistencies between the previously obtained ideas about the activated zones and the data of the Scheme. They are especially large in the Carpathian, Crimean and Donetsk regions, and are noticeable in others. Therefore, it seems necessary, first, to continue research, thicken the network of observations and develop a methodology for analyzing their results.

scholarly journals Geoelectric heterogeneities of the Kerch iron ore basin

2021 ◽  
Vol 43 (5) ◽  
pp. 165-180
Author(s):  
I. Yu. Nikolaev ◽  
T. K. Burakhovych ◽  
A. M. Kushnir ◽  
Ye. M. Sheremet
Keyword(s):  
Electrical Conductivity ◽  
Upper Mantle ◽  
Iron Ore ◽  
Earth’S Crust ◽  
Crust And Upper Mantle ◽  
Near Surface ◽  
Low Resistivity ◽  
Kerch Peninsula ◽  
Mud Volcanism ◽  
Earth's Crust

The three-dimensional geoelectric model of the Earth’s crust and upper mantle of the Kerch Peninsula has been built for the first time based on the results of experimental observations of the Earth’s low-frequency electromagnetic field, carried out in 2007—2013 by the Institutes of the National Academy of Sciences of Ukraine. Its physical and geological interpretation and detailing of the near-surface part were carried out according to the data of the audiomagnetotelluric sounding method to study the deep structure of the Kerch iron ore basin. To the east of the Korsak-Feodosiya fault along the southern part of the Indolo-Kuban trough (in the north of the South Kerch and almost under the entire North Kerch zones), a low-resistance anomaly (ρ=1 Ohm∙m) was found at depths from 2.5 km to 12 km about 20 km wide. Its eastern part is located in the consolidated Earth’s crust and is galvanically connected with surface sedimentary strata, while the western part is completely in sedimentary deposits. The anomaly covers the territory of the Kerch iron ore basin and occurrences of mud volcanism. The characteristics of the upper part of the layered section of the Kerch Peninsula in the interval of the first hundreds of meters were obtained from the results of one-dimensional inversion of the audiomagnetotelluric sounding data (frequency range 8—4000 Hz). It is shown that the first 15 m of the section, corresponding to Quaternary deposits, have resistivity values up to 1 Ohm∙m. Below, in the Neogene sediments, the electrical resistance increases to values of 5 Ohm∙m and more. Both horizontally and vertically, the distribution of resistivity values has a variable character, manifesting as a thin-layered structure with low resistivity values. Possibly, such areas have a direct connection with the channel for transporting hummock material and gases. A connection is assumed between the low-resistivity thin-layered near-surface areas, a deep anomaly of electrical conductivity in the upper part of the Earth’s crust, and the likely high electrical conductivity of rocks at the depths of the upper mantle with iron ore deposits, as well as the manifestation of mud volcanism. The heterogeneity of the crustal and mantle highly conductive layers may indicate a high permeability of the contact zones for deep fluids.

A BIOLOGICAL PROOF OF PETROLEUM EMANATIONS

Geophysics ◽  
1947 ◽  
Vol 12 (2) ◽  
pp. 281-282
Author(s):  
V. Thyssen‐Bornemisza
Keyword(s):  
Physical Structure ◽  
Earth’S Crust ◽  
Mineral Deposits ◽  
Surface Layers ◽  
Near Surface ◽  
Plant Life ◽  
Decomposition Of Organic Matter ◽  
Earth's Crust ◽  
The Many ◽  
Plant Components

“It cannot be denied that the chemical‐physical structure of the near surface layers of the earth’s crust reflect their physical characteristics and chemical composition in the plant life that covers them, in spite of the many retractions and changes which the science of Botany has had to make in this matter. The fact that many plants and plant components can store up metals has been recognized and utilized by miners and geologists, in that they correlate the occurrence of certain trace elements such as gold and lead in certain plants with corresponding mineral deposits. On the other hand the science of Applied Geophysics has long sought a useful method for proving and possibly determining quantitatively the presence of hydrocarbons which have migrated through the overlying formations to the earth’s surface. Hydrocarbons are found almost universally in the earth’s crust near the surface layers usually irrespective of whether or not an appreciable deposit of oil exists in the vicinity. For example, methane is formed as the result of the decomposition of organic matter. Evidence of the actual effects of mineral deposits is therefore generally either obscured or cannot be proved.

Deformations of the deep layers earth’s crust of the East-European platform

2020 ◽  
pp. 25-34
Author(s):  
V. M. Makeev ◽  
N. V. Makarova ◽  
T. V. Sukhanova
Keyword(s):  
East European Platform ◽  
Deep Structure ◽  
Earth’S Crust ◽  
Mantle Lithosphere ◽  
Near Surface ◽  
East European ◽  
Horizontal Stratification ◽  
Deep Layers ◽  
Earth's Crust ◽  
First Time

The article deals with the internal deep structure of the earth's crust of the East European platform and the surface of the mantle lithosphere. The presented charts of the three main layers of the earth's crust — the lower, middle and upper and the surface of the mantle lithosphere — for the first time identified deformation by changing the thickness of the layers. Deformations are compared on all layers that allowed to allot the active center, the main (through) and local (developed in separate layers) areas. The boundaries of these regions are active zones of different ranks. The observed end-to-end development of strain from layer to layer or expression of some of them only in separate layers indicates on the sub-horizontal stratification and vertical divisibility of the earth's crust. Deformations of the deep layers are compared with the latest near-surface platform structures. This made it possible to establish a connection of near-surface deformations with deep ones and to consider the latter as the latest. These studies are relevant for solving fundamental problems of the origin of new structures and a number of practical problems.

scholarly journals Geoelectrical inhomogeneities of the Crimean region as the seismicity and oil-gas potential zones

2021 ◽  
Vol 43 (1) ◽  
pp. 69-92
Author(s):  
A. Kushnir ◽  
T.K. Burakhovich
Keyword(s):  
Upper Mantle ◽  
Earth’S Crust ◽  
The Black Sea ◽  
Northwestern Part ◽  
Crust And Upper Mantle ◽  
Contact Zones ◽  
Crimean Peninsula ◽  
Near Surface ◽  
Conductivity Anomalies ◽  
Earth's Crust

The three-dimensional geoelectrical model of the Earth’s crust and upper mantle of the Crimean region and adjacent territories has been built for the first time. It is based on the results of the Earth’s low-frequency electromagnetic field experimental observations, conducted in 2008—2013 by the Institutes of the National Academy of Sciences of Ukraine. The subvertical conductive zones or contacts of the different resistivity mainly in the near-surface layers coincide with the fault structures, most of which are confined to the boundaries between the different tectonic elements, such as the Scythian Plate and Mountain Crimea, North and South Kerch Zones and the other faults: Chongarskiy, Melitopol-Novotsarytsynskiy, Korsarsko-Feodosiyskiy, Gornostaevskiy and Kerch-Chkalivskiy. The Mykolayiv and West Crimean fault systems occur as large separate submeridional conductive zone. Deeper in the Earth’s crust and upper mantle, geoelectrical inhomogeneities are transformed into the subhorizontal structures (layers) and manifest themselves in regional anomalies. This fact may indicate the high permeability for deep fluids of contact zones during their formation. The deep sublatitudinal structure in the Earth’s crust is confidently traced, in the west it confirms and details the well-known Tarkhankut anomaly, and continues through the central Crimea to the northwestern part of the Kerch Peninsula. It is assumed that there is the strong sublatitudinal anomaly in the interior of the northwestern shelf of the Black Sea and in the northeastern part of the Kerch-Taman Depression at the crust — upper mantle boundary, it is contouring the Crimean Peninsula. The ultradeep fluid manifestation zones obtained according to seismotomography, the conductivity anomalies in the Earth’s crust and the upper mantle, increased heat flow and the spread of the earthquake hypocenters confirm the relationship between the Crimea seismicity and collision processes. It is shown the spatial coincidences of the hydrocarbon manifestations and the isolated conductivity anomalies, which are characterized by subvertical channels galvanically connected to sediments, or subvertical contact zones of different resistivity, which are observed not only in the Earth’s crust but also in the upper mantle layers (60—90, 110—140 km) and may cause the superdeep fluid inflow.  

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