Results of the analysis of the earthquake in Japan with GPS
Accurate picture of the events leading up to the earthquake in Japan on March 11, 2011, restored by Japanese scientists using data from the satellite system GPS.
The powerful earthquake that struck Japan on March 11, 2011, which caused the deaths of more than 15,000 people and caused an accident at the plant 'Fukushima ", continues to be the subject of research geophysicists. We know that this earthquake occurred in the Japan Trench — the deep ocean basin, where the heavier oceanic Pacific plate dives under the continental Okhotsk plate that is part of the Eurasian continent, and some Japanese islands. As the oceanic plate dives into the earth's mantle in the Japan trench for hundreds of years accumulated tension that led to such a powerful earthquake, as the March 11, 2011.
In order to recover an accurate picture of what happened, the scientists collected and analyzed seismic data from around the world using satellite observations, where the Earth's crust, and collected data on the tsunami received stations on buoys in the ocean. Operate upon three research groups on research on the subject, published in Science in May.
Now, however, the results in the new issue of the journal Nature Japanese scientists reported Institute of geospatial information.
In their work they used data from satellite navigation system GPS (Global Positioning System).
The most powerful earthquake recorded by humanity in 1960 in Chile and had a magnitude of 9.5. Such power was caused largely by the fact that the cause of the earthquake was the fault of the lithospheric plates that are longer than 1000 km. In the event of an earthquake, which occurred March 11, 2011, it is a fault length 'only "400 km. But the release of energy was close to the surface of the Earth — in less than 20 km below the ocean floor.
In a paper published in Science, said that on average, offset plates in the subduction zone of the earthquake was 50-60 meters.
Japanese scientists in an article in Nature reported that the rise of the ocean floor in the quake was 27 meters.
This elevation and caused such a devastating tsunami that followed the earthquake.
As shown in the work, 15 years ago, according to the GPS you can install a slow accumulation of strain as a result of the Pacific plate motion.
However, suppose that in a few years this tension free up as much of a strong earthquake, it was impossible.
It was the time one should not expect a massive earthquake, but several minor seismic events that could not cause serious damage. This opinion was based on the fault of a few centuries of observations in the area observed a magnitude 8.7 earthquake, and occur every few decades.
Although Professor at Washington State University Joanne Bourgeois in a lecture in 'Gazeta.ru " talks about the Japanese colleagues, published in 2007.
In the publication with a probability of 99% in the next 30 years in Sendai, where the earthquake March 11, 2011, it was predicted an earthquake of magnitude greater than 8.2.
As shown by Japanese scientists, GPS can and should be used to monitor the movement of tectonic plates and the construction of the model to a more accurate prediction of seismic activity. These observations are needed: the main conclusion of the paper is that, because of the Japan Trench were not expecting an earthquake of magnitude 9, and it happened, then it is possible that this can happen in other seismically active areas.