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 Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>