Libmonster is the largest world open library, repository of author's heritage and archive

Register & start to create your original collection of articles, books, research, biographies, photographs, files. It's convenient and free. Click here to register as an author. Share with the world your works!
Libmonster ID: COM-854

Share this article with friends

Evolution of the Earth has been in progress for nearly 5 bn years during which time the planet has undergone substantial changes of material and structural nature. These changes have been investigated by several generations of researchers. But a host of problems in this branch of geology still remain unresolved. One of them is associated with linear structures-lineaments "cutting through" the body of our planet at different levels - from planetary to local. They are investigated by one of the rapidly developing branches of natural science - lineamentology.

Articles in this rubric reflect the opinion of the authors. - Ed.

Pages. 31

by Alexei ZHELOBAEV, Cand. Sc. (Geol. & Mineral.), Deputy Director General ZAO "SOVINTERVOD"; Dmitry KOCHEV, Cand. Sc. (Geol. & Mineral.), Head of Department of the same Society; Alexander MAKHORIN, Cand. Sc. (Geol. & Mineral.), Director General ZAO "TEKHNORISK", Lomonosov Moscow State University; Anatoly POLETAEV, Cand. Sc. (Geol. & Mineral.), Head of Lab of Geological Studies by Cosmic Methods, Geological Department of Moscow State University

The term "lineament" (from Lat. lineamentum - line) was brought into scientific circulation by the American geologist and geographer Dr. William Hobbs. He was referring to regularly repeating directions, or lines, determining the propagation of different geological structures and elements of relief: mountain ranges, rivers, oceanic coastlines, etc.

In an article, which looks more like a summary of a good dissertation, the scientist, later Michigan University professor (honoris causa) who was then searching for drainage channels of subterranean waters in Connecticut, identified for the first time linear structures of the earth crust in their latent forms and described in detail the algorithm of searching for them. And he did it with the typical American zeal for advertising. He did not try to "hide" his newly invented term in an article published in the 15th volume of the Bulletin of the American Geological Society (1904) put it into the headline.

Incidentally, as fate would have it, studies of linear structures developed in hidden form had been started some two years before the start of systematic investigation of rupture structures in an "open form"-which lend themselves to visual observations. And the sad "impetus" for these studies was the catastrophic Californian earthquake of 1906. It "brought back to life" the notorious San-Andreas rift which severed the earth surface with everything there was upon it: roads, storages, orange gardens, houses, etc. The concept of fracturing, or faults, was introduced into geological terminology by the famous plutonist Dr. John Pleifer back in 1802, but systematic studies thereof were "delayed" by more than a century.

And it would be only fair to say that the "terminological discovery of Prof. Hobbs was made not "all at once", but had been prepared by studies of geologists and geographers of the late 19th century. He must have known of similar works of the outstanding specialists of that time: Edward Zuss (Honorary Foreign Member of the St. Petersburg Academy from 1901) - for South Italy, Alexander Karpinsky (future member and President of the St. Petersburg Academy) - for Central Russia, Charles Kjerulf - for Norway, Nikolai Andrusov (Member of the St. Petersburg Academy from 1914) - for the Ponto-Caspian region, George Abikh (Honorary Member of the St. Petersburg Academy from 1866) - for the Precaspian region, French geologist Marcel Bertran (Foreign Member of the St. Petersburg Academy from 1899) - for whole continents.

In the beginning the ideas of Hobbs were supported by the leading geologists of that time. For example, Dmitry Mushketov (Russia) identified lineamental systems crossing the Mediterranean; Hans Stille (Germany) identified what were called the cardinal lineaments of Europe which, he believed, originated not later than the Protozoan, and his compatriot Richard Sonder suggested studying lineaments within the framework of lineament tectonics.

But later on, as it often happens in science, the notions of Hobbs, although not forgotten, were somehow ignored by geological theory and practice over more than half a century. And some separate, and even very successful works, like a monograph of Soviet researcher Ivan Chebonenko (1963) did not "carry the day".

Active interest to the ideas of Hobbs was revived in the 1970s with the appearance of pictures of the Earth taken from space. Their "decoding" proved that the surface of our planet is speckled with a great number of lineaments of different length and stretching in different directions and often crossing all structures located in their way. And it also turned out that most of these lines had not been discovered in the course of geological surveys.

Linear structures identified in decoding of space photos, posed at least two basic questions: a theoretical one, associated with the origin of lineaments and their development in the course of the evolution and changes of the Earth, and a practical one involving the assessment of contemporary tectonic activity of formations many of which run across the territories of cities, tunnels, dams of hydro-electric stations, sites of atomic power stations, etc. Active studies of these objects, which had not been identified by the traditional geological or geophysical methods, have led to a reassessment of certain notions, improvements of regional, geological models and helped solve a number of practical problems.

Significant contributions to the development of various aspects of lineamentology have been made by many Russian and foreign geologists.

The integrations of data about structures and systems which interest us has led to the formation and intensive development of a new area of research which has been justly called "lineamentology". One of the authors of this arti-

Pages. 32

Diagram of cardinal lineaments of Europe (by G. Stille).

Planetary lineaments of the Eastern Hemisphere - of the North Sea-Indonesia (I-I) and Africa-Chukotka (II-II) reflecting the borders of the "blocks" of the Earth and characterized by reverse correlations between the elevated (+) and lowered (-) fragments of day-time surface: 1 - lineaments, 2 - zone of intensive inter-block erosion of the Earth crust.

cle - Dr. Anatoly Poletaev, says this discipline focuses on manifold studies of what they call linear formations of the Earth and planets of its group. These studies are focused on the role of the formation and development of the solid, liquid and gaseous envelopes of these planets.

All that has been accompanied by active development and introduction into all kinds of geological studies of what we call specific effective and high-rate analysis - the basic method of lineamentology. It exists in three versions: visual (manual), computer and "mixed". In the first case the main "tools" of the operator are his own eyes and hands. Using aerial and space photos, maps and diagrams, he can trace and identify hidden linear structures. In computer decoding the search for and the identification of such structures and their statistical processing are conducted in an automatic mode using special programs, such as the LESSA one developed in the 1980s by Russian scientists. In the third case a researcher, using a computer, can obtain all kinds of data such as the lineaments of concrete formations, the nature of their interactions in space, etc.

Needles to say that such technological possibilities of contemporary lineamental analysis boost its "informative potential", objectivity and authenticity. On the theoretical level, systematic studies of the Earth from the positions of the suggested doctrine should help us produce what we call a new global geodynamic model. In this connection it would be appropriate to recall a report delivered at the Lomonosov State University by Acad. Viktor Hain on April 10, 1997. Describing the main requirements for "the new truly global geodynamic model, he said the main drawback of the contemporary plate-tectonic concept consists in the integration of the global, lawfully oriented network of lineaments. And apart from that the lineamental field of the Earth is also characterized by several other fundamental parameters: by its autonomous and "priority" factors, planetary (along the horizontal), fractality (by the vertical), conservativity and revelatory (reflectivity), rhythmical and (or) equidistant features, its isotopic and anisotropic features, its multilineamental and/or "translationary" features.

Autonomous and priority characteristics mean that any linear elements of a geological structure of different origin (ruptures, joints, crevices etc.) and "ranks" (planetary, regional, local) represent but different fragments of a lineamental formations of an equal size.

Planetary characteristic (along the horizontal) reflects the quality of lineaments to be "traced" over giant distances, being "traced" under most different structures-ancient platforms or young folding mountain belts, under present-day seas and oceans. One such example is the Lavrasian system of lineaments with sub-latitudal orientation which can be clearly traced across the Baltic shield, the early Russian plate, across the submeridionally oriented Urals folded belt and across the young West - Siberian platform, the ancient East-Siberian platform, the Pacific Folding belt, the water area of the Pacific, the folded belt of the North American Cordilleras, the ancient North-American platform, etc.

A no less vivid example of the transient nature of lineaments and their systems is linked with the assessment of the in-depth connections of the platforms of Eurasia and Gondwana: thick strata of the Mediterranean folded belt, which is "hiding" the actual wedge-shaped links of these structures were unable to interfere with a reconstruction

Pages. 33

Wedge-shaped nature of the plutonic interconnection of the platforms of Eurasia and Gondvana (initial scale 1:2,500,000): a - Mediterranean folded belt; b - platforms; c-f - lineaments and their progressions: c - submeridional, d - sublatitudal, e - north-eastern, f - north-western; g - wedges produced by lineaments; i-j - directions of wing shifts: l - vertical, j - horizontal; k - direction of compressive stresses; I - names of submeridionai lineamental zones: I - Pyrenean, II - Alpine, III - Balkanian, IV - Crimean (Anatolian), V - Caucasian, VI - Kopetdagian, VII - Himalayan.

with the help of the lineamental analysis. Its results were reported by Acad. A. Poletaev (with coauthors) at the 27th session of the International Geological Congress in Moscow (1984) and confirmed by independent geophysical studies conducted in the 1980s under the leadership of Dr. Yuri Shchukin of the All-Union Research Institute of Geophysics.

Conservative revelatory (reflectivity) characteristics consist in the preservation of the basic lineamental matrix, e.i. the combination of linear structures of orthogonal and diagonal direction established in the decoding of space photos of different scale. That, of course, does not exclude the possibility that in every concrete region and at every concrete level of generalization we observe certain predominant direction of lineaments which attests to the anisotropic nature of the lineamental field.

Rhythmicity or equidistant feature is associated with the principle of "equidistant location of geological structures" which was formulated in the past century of the French geologist Auguste Daubree.

At the start of the 20th century Prof. Hobbs demonstrated that: "The normal interval of the meridional series is in the latitude of Boston about 40 miles; that for the northwest-southeast stretching series is about 75 miles, while that for the northeast-southwest series approximates 125 miles." And approximately in the 1970s Czechoslovak geologist V. Nemetz produced a formula of discretion of geological structures; Vx =2-x D where V is the distance between the lineaments, x - order of the structure, D - Earth diameter.

In some cases knowledge of the rhythmicity of the lineamental field makes it possible to conduct in a more authentic way the search for, identification and mapping of concrete lineamental structures and their systems.

The multilineamental feature of such systems depends on the fact that separate lineaments and their systems produce a lineamental field of a complicated integral infrastructure, which is common geodynamically. It is a multilayer structural framework - carcass (core-mantle-Moho* surface - foundation - sedimentary shell-daytime surface). It is expressed, as a rule, in a latent form. Nevertheless the lineamental field influences not only the evolution of the structurization of the Earth crust and the Earth as a whole, but also contemporary geodynamics, as if predetermining and controlling the inception, development (direction) and sometimes the intensity of both endogenic (seismicity, volcanism, etc.) and also exogenic processes and phenomena (landslides, karts, suffusion, erosion, etc., and also regularities and peculiarities of metallogenics as outlined by Acad. Vladimir Smirnov in the 1980s and Prof. Valentina Afanasyeva in 1990.

Fractality or transitivity (by vertical) are illustrated by the repatition of drawings of linear structures at all - from planetary to local - levels of investigations of the Earth crust. Of

* Moho (Mohorovicic) surface - border (divide) between the earth crust and mantle, determined by "jump" of velocities of seismic waves. - Ed.

Pages. 34

Diagram of linear dislocation of the earth crust on the territory of Moscow megalopolis (initial scale 1:200,000, inserts 1:1,000,000). 1 - karst sink holes.

Propagation of radon concentrations in Russia's central regions (according to Ignatov and Lykhin, 1998): 1 - regional breaks of deep location exposed to the latest activation; 2 - regional zones of increased accumulations of helium; 3 - borders of the Podmoskovny brown-coal basin; 4 - foci of discharge of deep underground waters of the Moscow artesian basin; 5 - manifestations of stratiform uranian ore formation of the uranium-coal type; 6 - ore manifestations; 7 - areal anomalies; 8 - increased radon concentrations in ground water; 9 - regions with high radon concentrations.

special importance here are X-, T- and V-shaped combinations of lineaments forming what are called junction structures. These are characterized by increased fractionation of the Earth crust, geodynamic mobility and fluidopermeability. Junction structures are of multifunctional importance for different processes: from the formation of blast pipes to activation of karst precipitations. And it is significant that even mathematicians, such as the British scientist Michael Atiyah, regard junctions to be "surprisingly complicated objects" which "do not lend themselves to exhaustive interpretations".

One striking example of such junction structure is the territory of the Moscow megalopolis located at the crossing point of big lineamental zones of meridional, sub-latitude, north-eastern and north-western extensions, and on the local scale-speckled by numerous finer linear structures. The possibility of their activation at the present stage of development of the Earth crust in this region has not yet been investigated.

Many researchers have arrived at a practically unanimous conclusion: studies of the structure and development of the Earth crust and of the planet as a whole will be far from complete without taking into consideration of the lineamental component because structures hidden under overlaying rocks are responsible for the regularities of development of catastrophic processes - earthquakes and landslides, karst caverns and volcanic eruptions and also of deposits of oil and gas, diamonds, gold, etc.

Arguments about the origin of lineaments are likely to continue for a long time. But one of the clear achievements of geology of the late 20th century consists in the fact that from kind of "unidentified linear objects" of the Earth crust, to which they belonged only yesterday, today these structures become real elements of the geological environment. Comparison of these structures and their systems with the available geological and geophysical data has proved that: on the surface of the Earth lineaments reflect in-depth linear homogeneities with their "roots" capable to reaching even the core of our planet; in particular, lineaments kind of "trace" on the surface fractures in the body of the crystalline foundation, or base, of the Earth crust or reflect dislocations in the normal occurrence of strata of the sedimentary mantle, etc.

However, we do not understand to this day the mechanism of relaying (translation) of a lineamental "signal" from, say, a fracture of the crystalline foundation of a platform through its practically underformed mantle to the day-time surface of the Earth crust. This problem, incidentally, was discussed at a special session held on April 15, 2005 at the Dubna International University of Nature, Society and Man. It was conducted on the initiative of Prof. Nikolai Koronovsky Head of the Chair of Dynamic

Pages. 35

Attachment of the focal zone of the Agadir earthquake to the crossing point of submeridional and sublatitudal lineamental zones (according to Kozlov, Katz and Sulidi-Kondratyev). 1 - Isoseists of Agadir earthquake in points; 2 - Ruptures traced in geological mapping; 3 - Flexures expressed in surface structure; 4 - 5 - Rupture zones: 4 - Periatlantic, 5 - South-atlassie.

Ratio of zones of lineaments and their crossing points with kimberlite fields of the Yakut kimberlite province.

Geology of the Chair of Geology of the Lomonosov Moscow State University, who is also head of the Chair of Ecology and Earth Science of the "Dubna" University. The discussion was conducted with the active support of the "Dubna" University Rector, Prof. Oleg Kuznetsov. Taking part in the discussion were lecturers of the aforesaid chairs and of the RAS Institute of Geoecology. Their working model was a mechanism suggested by Dr. Mikhail Goncharov connected with the action of high-pressure fluids generated in the process of degassing of plutonic strata of the Earth.

In any case, many geologists are convinced that the modern structure of the Earth crust and its development in the geological past are the result of a constant rejuvenation of one or the other part of the ancient lineamental framework, and that the existing ruptures and zones of fracturing marked on geological and tectonic maps of different scales are nothing but a particular case of manifestation of exactly these lineaments.

Thus the linear structures under consideration posses a dual structure - on the one hand these are kind of "healed" breaking damages, and on the other these are lines of the present-day pre-rupture condition of the crust. And it is clear that in the latter case they are of special interest - not only theoretical, but practical, because they have to be taken into consideration in designing, building and utilization of all kinds of structures such as nuclear stations and storages of nuclear wastes, dams of hydro-electric stations, underground (subway) lines, bridges, oil and gas pipelines, etc.

At the present time many researchers come to the conclusion that lineamentology is not a prerogative of geology alone. This is rather an inter-disciplinary branch comprising problems of science and interests of geology, geography, soil science, ecology and other branches of knowledge. And the connections of certain linear structures, zones and joints of their interconnection and/or cross-sections with zones of increased concentrations of radon conveys to them a tangible social status by making it possible to identify and map what are called geopathogenic zones.

According to their scale, nodes are divided into units of planetary, regional and local levels. The first includes the nodal structure of the Eastern hemisphere - the area of cross-section of the North Sea-Indonesian and Africa-Chukotka lineamental zones of the north western-south eastern and south western-north eastern stretches on the territories of Iran and Afghanistan. These giant linear structures are interesting not only because they divided the Eastern hemisphere into four sectors whose existence attests to in-depth deformations on the level of the core-mantle border.

From the south-west the lineament of the North Sea-Indonesia is joined by a very fractured territory. It is "squeezed" between some more or less "monolith" blocks of the Earth crust from the north and by Eurasia from the north-east, and from the south and south-west - by Africa and Australia, separated by the Indian Ocean. This region is a zone of intense inter-block decomposition.

The more we study lineaments, the more often we discover their logical links with most different processes and phenomena in the Earth crust. For example, comparison of data of the linear structures and the map of seismic zoning of the Alpine belt of Eurasia has shown that those of them which cross mountain structures of the Carpathians, Crimea, Caucasus, Kopetdag and Pamir kind of "split" these territories into separate blocks with peculiar manifestations of densities of earthquakes, their force, depth, etc.

Pages. 36

Hidden linear distortions of the Syrian coast of the Mediterranean established with the help of lineamental analysis (initial scale 1:100,000).

Studies with the help of space photographs of the foci of some Earth quakes such as the Agadirsky one in the West of Africa, or whole seismically active regions, like the Gazly one in Central Asia, have led scientists to the conclusion that the foci of these events are often confined to the crossings or combinations of separate lineaments stretching in different directions. The same can be said about the gravitations of volcanic manifestations and the locations of various mineral deposits. The most vivid example is provided by kimberlite blast pipes (including diamond-bearing ones).

"Catching up" with endogenic processes are exogenic ones: the biggest karst sink holes or sags of soil, landslides and sags of surface soil are connected (as was demonstrated in 1997 by A. Gorshkov and M. Zhidkov) with the size of the nodes of cross-sections of lineaments, their zones and systems. Regularities discovered during studies of tectonics and engineering-geological processes developed on the territory of the Northern Caucasus make it possible to single out from general lineamentology a special, engineering branch. In 1999 it was effectively tested (by a team of scientists including A. Makhorin, E. Kuchukov and A. Poletaev) who were searching for hidden linear flaws in the Moscow metropolitan region. And quite recently a team of A. Zhelobaev used the same method in the identification and studies of similar approaches to the Syrian coast of the Mediterranean. Studies of this kind must, in particular, optimize searches for the safest sites for the construction and functioning of hydrotechnical units.

The proposed method and direction of research acquire at the present stage of geological explorations, which are

Pages. 37

Sectoral structure of Mars (according to Pinet, Chevrel, 1990). White-high ratio of brightness intensities observed for elevated regions (+), black-low ratio typical for depressed regions (-), grey-intermediate values. Clearly seen are 4 sectors: Arabia Land ++, flatland Hellas +, flatland Big Siret --, Noah's Land-.

characterized in our country by a sharp reduction, of not complete absence of field studies. That also applies to studies of planets as has been repeatedly demonstrated on the examples of Mars, Venus and other planets and their satellites.

For more than 100 years, we know, many scientists and science fiction writers focused their attention on what were called Martian channels discovered in 1877 by the Italian astronomer Jovanni Schiaparelli. All kinds of suggestions were made about their origin and the miracles of Martian civilization. Science fiction writers were trying to prove their "artificial" origin. But then came space photos of the Earth and planets of its group and fairytales were abandoned, because there was more than enough of such channels on other planets, like Venus where life is simply impossible. And these formations again turned out to be lineaments.

Lineamental analysis of space photographs led researchers to what we call a fundamental planetary "regularity" - the sectoral "structure" of planetary bodies. It was established in particular by Dr. Gennady Kochemasov for Mars and other planets.

It was established that the same kind of analysis if promising in studies of solid planetary bodies, but also those in a state of what we call glaciotectonic melange- a chaotic mixture of fragments of rock and ice which is characteristic of Ganymede - one of the satellites of Jupiter (studies conducted by a team of specialists from the Moscow State University - Edward Yershov, Anatoly Poletaev et al.).

An important breakthrough in our knowledge of the structurization of the Earth and planets of its system loomed on the horizon after the discovery in 1999 by Dr. Anatoly Poletaev, Dr. Andrei Avdonin and Dr. Fyodor Kotov of the so-called deviant lineamental structures. Their presence attests to a rotary nature of the structure-forming processes. By the present time they have been identified not only for different regions of the Earth, such as the East-European platform and Syrian coast of the Mediterranean, but also for the satellite of Jupiter-Ganymede, as demonstrated by the aforesaid team of scientists from the Moscow State University.

Thus general lineamentology, after an age-long path of development, which provided a tangible contribution to our knowledge of the structure of the Earth and some other planets (and their satellites) of its group, has sufficient inner resources for its development and splitting out in the future into a number of special branches, above all planetary and regional ones, historical and dynamic, engineering and ecological, social, etc.

And last, but not least. Would you like to imagine yourself a lineamentologist? If so, take any available geographical map - best of all a contour map of European Russia. You will see that the biggest rivers - the Dnieper, the Don and the Volga bend and flow first in the meridional direction-from the north to the south and then from the north-west to the south-east and from the north-east to the south-west. Prof. Hobbs suggested identifying the lineaments by the straight sections of the river valleys and we now have to do is link, in your imagination, or on the map, similarly oriented sections of river valleys and then you get lineaments drawn up by your own hands and reflecting the structures of the Earth crust at different depths.

If one draws a line from the lower reaches of the Danube and along the north-western and almost straight coast of the Sea of Azov and then along the lower reaches of the Don and then, bypassing the sharp "bend" of the Volga valley near Volgograd and moving along the northern edge of the Precaspian depression, you finally get a very interesting and puzzling linear structure. Prominent Russian scientists Prof. Igor Vinogradov and Prof. Yuri Shchukin called it "a zone of attenuation of seismic oscillations". It is a kind of a screen for the penetration of waves of Caucasian earthquakes into the "body" of the East European (Russian) platform. On meteorological maps the same kind of line is construed as the border of the "first thawing" - in spring the thawing of the snow cover is most intensive along this line, thus stressing the close connection between the plutonic and surface processes on our planet.


Permanent link to this publication:

Similar publications: LRussia LWorld Y G


Libmonster OnlineContacts and other materials (articles, photo, files etc)

Author's official page at Libmonster:

Find other author's materials at: Libmonster (all the World)GoogleYandex

Permanent link for scientific papers (for citations):

Alexei ZHELOBAEV, Dmitry KOCHEV, Alexander MAKHORIN, Anatoly POLETAEV, LINEAlMENTOLOGY: FROM FACTS TO BRANCH OF SCIENCE // London: Libmonster (LIBMONSTER.COM). Updated: 27.09.2018. URL: (date of access: 06.12.2021).

Publication author(s) - Alexei ZHELOBAEV, Dmitry KOCHEV, Alexander MAKHORIN, Anatoly POLETAEV:

Alexei ZHELOBAEV, Dmitry KOCHEV, Alexander MAKHORIN, Anatoly POLETAEV → other publications, search: Libmonster United KingdomLibmonster WorldGoogleYandex


Reviews of professional authors
Order by: 
Per page: 
  • There are no comments yet
Related topics
Libmonster Online
New-York, United States
314 views rating
27.09.2018 (1167 days ago)
0 subscribers
0 votes
Related Articles
Catalog: Science 
4 days ago · From Libmonster Online
Catalog: Political science 
4 days ago · From Libmonster Online
Catalog: Other 
35 days ago · From Libmonster Online
Catalog: Biotechnology 
35 days ago · From Libmonster Online
Catalog: Astronomy 
66 days ago · From Libmonster Online
Catalog: Physics 
76 days ago · From Libmonster Online
Catalog: Library science 
80 days ago · From Libmonster Online
Catalog: Astronomy 
80 days ago · From Libmonster Online
Catalog: Astronomy 
80 days ago · From Libmonster Online
Catalog: Science 
98 days ago · From Libmonster Online

Actual publications:


Libmonster is the largest world open library, repository of author's heritage and archive

Register & start to create your original collection of articles, books, research, biographies, photographs, files. It's convenient and free. Click here to register as an author. Share with the world your works!

Watch out for new publications:

About · News · For Advertisers · Donate to Libmonster

Libmonster ® All rights reserved.
2014-2021, LIBMONSTER.COM is a part of Libmonster, international library network (open map)
Keeping the heritage of Ukraine


US-Great Britain Sweden Serbia
Russia Belarus Ukraine Kazakhstan Moldova Tajikistan Estonia Russia-2 Belarus-2

Create and store your author's collection at Libmonster: articles, books, studies. Libmonster will spread your heritage all over the world (through a network of branches, partner libraries, search engines, social networks). You will be able to share a link to your profile with colleagues, students, readers and other interested parties, in order to acquaint them with your copyright heritage. After registration at your disposal - more than 100 tools for creating your own author's collection. It is free: it was, it is and always will be.

Download app for smartphones