Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Wind is swaying the Earth

28.09.2005


The upper layer of the earth’s crust may be investigated using high-rise buildings’ vibrations under the wind pressure. This simple and economical method of seismic survey was developed by the specialists of the Arkhangelsk Institute of Ecological Problems of the North (Ural Branch of the Russian Academy of Sciences) and the Schmidt Institute of Physics of the Earth (Russian Academy of Sciences) under the guidance of F. N. Yudakhin, Corresponding Member of the Russian Academy of Sciences. The method was born from revision of the active snap location in the earth’s crust in the Arkhangelsk Region, at the Northern Dvina mouth.



Winds are rather strong in the surface atmospheric layers. Internal whirlwinds occur, creating wind surges. Wind impulses cause vibrations to the objects protruding from the relief for 10 meters and more, these vibrations, for their part, being transmitted to the earth’s crust. A Russian scientist B.B. Golitsyn considered possibilities of this effect back at the beginning of the last century. However, field observation did not provide distinct results at that time due to equipment imperfection. Contemporary experiment equipment, including digital recording and methods of weak signal extraction allow to solve such tasks and to use results for deep sounding of the earth’s crust.

Protruding elements of the relief may be both natural (mountain peaks, rock pillars) and artificial ones (towers, hoisting cranes, high-rise buildings). Their vibrations under the wind are described in a well-known task about vibrations of a rod with fixed end. In reality, the object is never rigidly fixed and it transmits vibrations via its foundation to geological environment. Thus, shuddering under blasts, any sky-scraper or hoisting crane turn into a peculiar seismic source emitting its own signals. Such sources are much more convenient than vibrating oscillators, which are commonly used for the earth’s crust survey.


The first advantage is that constructions more than 10 meters high irradiate low-frequency seismic signals of 5 Hz and below, that is within the frequency band of deep seismic sounding intended for research of the earth’s crust and upper mantle. Normally low-frequency signals are obtained with the help of explosions in water, powerful pneumatic irradiators or hundred-ton vibrators. High-rise constructions tremble constantly, even if the wind is weak. The second important advantage of wind vibrations is that they send a signal of stable frequency. The shape of a construction is invariable, therefore the signal frequency may be impacted only by the change of construction’s effective stiffness, for example, total glazing of balconies in a high-rise building. But researchers’ observations of a 44-storey Moscow sky-scraper showed that these changes were insignificant. The next point important for obtaining a stable seismic signal sounding the environment – is concordance of vibration source and the soil. The seismic vibrator first “tramples down” the soil where it is installed, but a steady picture can not be expected until the seismic vibrator finally condenses the soil. A signal from the artificial construction may be used immediately, without a transition period.

Nevertheless, the method also has shortcomings. The wind is blowing at different velocity, therefore, wind vibrations have a non-constant amplitude. This inconvenience can be avoided in two ways. Additional vibration recorders can be installed in the vicinity of the source, and then readings of all devices are to be compared. Changes in vibrational amplitude of each construction can be statistically evaluated and the researchers can further work with one station.

In any case, vibrations caused by wind influence on high-rise constructions may be used for seismic survey of the earth’s crust upper layer. Such scheme is simple and economical, which is important in the course of reconnaissance for selecting areas for more detailed survey, particularly in almost impassable regions. Relay towers are installed almost everywhere. Research by the Russian scientists is not only of application importance but also of fundamental significance: wind vibrations – are one more way of interaction between the planet’s geospheres, atmosphere and the earth’s crust.

Sergey Komarov | alfa
Further information:
http://www.informnauka.ru

More articles from Earth Sciences:

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

nachricht Modeling magma to find copper
13.01.2017 | Université de Genève

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>