The word seismology in Greek means "earthquake science." It carries out complex, but extremely necessary studies, since with their help experts predict the movement of the earth’s surface, study the structure of the subsurface and the processes occurring in them, develop methods to reduce losses after strong earthquakes, monitor nuclear weapons tests, and help in the search for minerals.
In this article, we consider the history of this science, what it does, and analyze synonyms for the word seismology.
The beginning of the development of science
In the eighteenth century, John Michel suggested that earthquakes cause elastic waves to pass through the earth's surface.
In 1760, he published the book "Assumptions about the causes of earthquakes and observation of this phenomenon." It confirmed the conclusion that rocks located in miles below the earth’s crust create waves that cause earthquakes. Seismology began to develop as a science.
Michel also put forward the theory that by comparing the data on the time the waves travel to a particular place, one can determine where the epicenter of their occurrence is located. Based on this method, modern methods for finding the epicenter were created.
First world catalog
The mid-nineteenth century became a new round in the development of science. In those years, according to the results of his twenty-year observations of the 6831 earthquake and field experiments, Robert Mallet compiled a catalog of world seismic activity.
In it, for each case, such characteristics as location, date, number of shocks, duration of oscillations, their possible direction and consequences were indicated. Photos were attached as evidence.
Later, systematic observations and registration of phenomena began to be carried out in many countries, including the USA, Russia, and Japan.
Earth's seismicity, or why earthquakes occur
The planetary feature of the Earth is recognized as its volcanism and seismicity. Active volcanoes and tectonic earthquakes are ways to implement them to get rid of the tectonic energy constantly accumulating in the thickness of the planet.
The basis of such grandiose processes are two events:
- fault occurrence (leads to seismicity),
- the formation of molten lava (leads to volcanism), which become a reaction of the internal environment to external loads.
The main reason that causes such phenomena on Earth is the principle of minimizing the gravitational potential energy (tension) in the bowels of the planet. Seismology and volcanology are called upon to study these phenomena.
In 1995, a team of scientists suggested that earthquakes could change the shape of our planet. As a result of these phenomena, it takes on a more circular and compact form, and this process occurs with a decrease in its gravitational energy by the transition to heat.
What is seismology for?
This is a science, thanks to which the principles of the Earth’s structure were revealed and the main boundaries of the division of its bowels - the core, mantle and crust - were determined. Scientists have found that along with data on the source of the earthquake, the oscillations provide information about the medium that propagates them.
The science of waves makes it possible to understand the nature of the formation of earthquakes in many respects, which helps in the development of new technologies for the construction of structures that are more resistant to earthquakes, which will save the lives of many people, as well as in many other areas.
It took science people more than a hundred years to understand that earthquakes are related to the seismic waves they create. And almost fifty years it took to get a common understanding about the internal structure of the subsoil and the properties of the propagation of seismic waves in them.
In parallel with this science, other, similar problems are dealt with, combined research is of great practical value.
Similar sciences
The names of the following sciences are considered synonymous with seismology:
- Geology (taken from ancient Greek). This is a broader concept. It is a complex of sciences about the internal structure and composition of the Earth, its development and origin. The results are based on the study of geological phenomena, the composition and structure of the earth's surface and lithosphere using all available methods, as well as data from disciplines.
- Seismography. Section of seismology. As part of this discipline, wave oscillations of the earth's crust are recorded by a special apparatus - a seismograph.
- Helioseismology (from English). It is a branch of astronomy that studies the internal kinematics and structure of the Sun according to how seismic and acoustic waves propagate.
- Seismometry is a part of seismology that is engaged in the development of methods and instruments for the purpose of recording wave oscillations of soil, structures and other objects when they are affected by seismic phenomena.
- Geophysics (from ancient Greek), in other words - the physics of the Earth. This is a set of sciences that investigate the structure of the Earth by physical methods.
The subject, object and tasks of the study of earthquakes
To understand what seismology is studying, you need to pay attention to what is being studied in the framework of this science: the object of its study is the movements of earth platforms and earthquakes, and the subject is the internal structure and structure of the planet. In particular, what effect does deviation from the homogeneity of matter inside the Earth have on the propagation of oscillations.
Such phenomena as earthquakes are considered to be specific, periodically repeating oscillatory movements of the earth's surface. Their characteristic property is a short duration - from fractions of seconds to tens of minutes. In this context, seismicity implies the geographical pattern of the distribution of earthquakes associated with the structure of the earth's surface and magnitudes (or stored energy).
There is also a section such as mine seismology. This is the direction, whose tasks include monitoring seismicity in those places where mining enterprises are developing, and forecasting with a subsequent warning about where an earthquake can occur. These steps are taken to ensure the safety of mining operations.
Purpose of research
The practical goal of seismology is to provide long-term forecasts of the possible places of occurrence of earthquakes, their repeatability and strength.
When the earthquake foci are studied, specialists conduct detailed studies of the phenomena and the processes occurring during them in real physical and geological environments. The displacements of the blocks of the earth's surface and other transformations are also analyzed, and the parameters of the focus are estimated. This allows us to identify earthquake precursors and develop operational short-term forecasts of their onset and duration, as well as methods for managing such processes. It is important to assess the possibility of anthropogenic or anthropogenic impact on seismic activity.
The tasks of seismology as a science include:
- study of seismic wave fields caused by earthquakes in the immediate vicinity of the focus of the phenomenon;
- study of strong seismic movements of the earth's crust;
- analysis of the interaction of the soil with the building located in the danger zone;
- development of methods and seismic microzoning;
- study of the effect of earthquakes on the planet’s atmosphere and hydrosphere;
- study of seismic noise on the surface of the Earth - microseisms.
The applied task of the engineering-seismological direction of seismology is the recognition and registration of underground nuclear explosions during tests.
Observation as a method for studying seismic activity
Seismology is closely related to seismometry, which is engaged in the development of instruments and methods for recording seismic vibrations.
Seismological research includes:
- visual observation of earthquake phenomena;
- registration with the help of equipment of excited seismic vibrations in both ranges - frequency and dynamic.
Waves are fixed by special instruments - seismographs. With their help, the place of occurrence and characteristics of the earthquake source are determined.
Seismographs are divided into:
- Stationary - designed for continuous operation, and the place of their installation are seismic stations connected in a network. Observations are made in this network, catalogs of phenomena are created, work is underway to study underwater earthquakes, and information is being made about upcoming crust movements.
- Expeditionary - located in the centers of strong fluctuations that have already arisen in order to record further possible shocks. These can be important construction projects, such as nuclear power plants or the bottom of the sea (ocean).
This equipment makes it possible to identify newly formed tectonic faults, displacements of the earth's crust, landslides, landslides and other geological disasters.