The waves on the lake can cause “micro-earthquakes”

Microseismic waves can travel at 30 kilometers from the coast.

Scientists have stated that the waves that appear on the surface of lakes, can cause micro-seismic waves that travel at 30 kilometers from the coast.

It is known that waves on the surface of the seas and oceans lead to the formation of microseisms seismic waves of small amplitude. Such waves can travel on land for a few tens of kilometers from the coast. They occur when approaching surface waves in fluids to shore due to the fact that the depth of the reservoir gradually decreases and the oscillations transmitted from the liquid earth’s crust. Type and frequency formed of seismic waves depends on the frequency of the waves in the liquid but may range, for example, due to nonlinear mivanova interaction.

Microseisms formed ocean waves have a period from two to 20 seconds. Now, researchers have assembled the currently available data and measured seismic signal near several unexplored lakes. As a result, scientists have detailed seismographic data for six lakes: Ontario, Yellowstone and the Great Slave lake in North America, and Fuxian, Erhai and Dianchi in China. Scientists say that these lakes are quite different from each other in size (from 210 to 27 thousand square kilometers) and are located in different climatic and seismic conditions.

Was that close to all the lakes you can really register very weak seismic waves with a period of oscillation of about one second. In addition, for lakes, the surface of which is covered in winter ice, a characteristic peak in the seismogram associated with these microseisms, almost disappears in the cold season and reappear when the ice melts.

The period of oscillations of microseismic waves from the lake much less period ocean microseisms. This effect, scientists explain that the surface of the lake is much smaller and the formation of waves the wind has a smaller area of dispersal, which weakens its impact and increases the frequency of the wave. In addition, in contrast to those seismic waves, which are produced by the ocean waves from the lake cover only 25-30 kilometers from the coast, which is associated with smaller amplitude and a fast attenuation of the generated surface acoustic waves.

Previously, scientists came to the conclusion that the deepest earthquakes may be a seasonal phenomena. According to scientists, the seasonal trend is not observed for small earthquakes or small tremors. Seasonal are earthquakes with magnitude above 7 points and occurring at a depth of more than 500 kilometers. The reason for this behavior of earthquakes scientists can’t explain.

paradox