Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Underground Water Regulates Earthquakes

14.09.2007
Earthquakes happen to be surface (shallow-focus), intermediate and deep ones. Seismologists mark out the boundary between the first two types at the depth of about 70 kilometers, its nature being still unclear. Russian researchers, specialists of the Institute of Maritime Geology and Geophysics (Far-Eastern Branch, Russian Academy of Sciences), Geophysical Center of the Russian Academy of Sciences and the P.P. Shirshov Institute of Oceanology (Russian Academy of Sciences) have put forward a hypothesis that the seismic boundary is simultaneously the lower boundary of hydrosphere. The earthquakes character depends on underground water.

Earthquakes taking place “at different sides of the boundary” differ from each other not only by the depth. Shallow-focus earthquakes – they account for about 85% of all recorded events - often take place under the influence of periodic external effects, for example, rising tides, which disturb the entire lithosphere of the Earth. Periodicity is not inherent to deeper earthquakes, they always occur by chance. The conclusion was made by the researchers who had analyzed the world ISC/NEIC catalogues data that covers the 1964-2005 period and takes into account about 80,000 events.

Seismologists connect existence of the 70-kilometer boundary with water state changes in the interior of the Earth. The deeper the water molecules are located, the more compressed they are. At the depth of about 70 kilometers, the water compression strain index increases up to 1.3. This is the way water molecules are squeezed in the crystal lattice. Above this boundary, water exists mainly in free phase, below the boundary – water embeds into the rock crystallite composition.

The rock containing free water (above the boundary) promptly reacts to periodic tidal effects, even the faintest ones. Pressure changes and respective environment density changes cause formation of a crack system, where free water rushes to. The cracks widen, increase, and rock decay gives birth to a seismic focus. In the rock, where free water is absent (below the boundary), weak tidal effects are not accumulated and deformation does not grow.

So, the seismic boundary at the depth of about 70 kilometers (where, according to the researchers’ assumption, the lower hydrosphere boundary runs) separates the events that are able to react to external action and the ones incapable of such reaction. Therefore, this boundary separates different types of earthquakes. However, it is still a hypothesis that requires experimental validation.

Nadezda Markina | alfa
Further information:
http://www.informnauka.ru

More articles from Earth Sciences:

nachricht Modeling magma to find copper
13.01.2017 | Université de Genève

nachricht What makes erionite carcinogenic?
13.01.2017 | Friedrich-Schiller-Universität Jena

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

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

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>