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For the first time, Japan has issued a warning over the possibility of a mega-earthquakeafter a 7.1 magnitude earthquake struck the country on Thursday, causing little damage.
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Japan’s meteorological agency reported that the risks of a large-magnitude earthquake occurring around the Nankai Trough or depressionwhich runs along the Pacific coast, have become higher than normal, issuing the first such advisory.
A group of experts studying the Nankai Trough said the chances of a megathrust earthquake occurring after a magnitude 7 quake were now higher than usual. Earthquakes of magnitude 8 or higher are considered megathrust earthquakes.
The next megathrust earthquake originating in the Nankai Trough is expected to be as large as 9.1. A megathrust earthquake triggering a large tsunami could result in hundreds to thousands of casualties and millions in losses in Japan.
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Images of the latest earthquake in Japan
Although the advisory does not include evacuation orders, Professor Naoshi Hirata of the University of Tokyo, who chairs the advisory group, said at a news conference that residents in areas that could be affected by the disaster should review routine earthquake preparedness and remain alert for about a week.
What is the Nankai Trough and why is it so dangerous?
The Nankai Trough lies off the southwest Pacific coast of Japan and stretches for approximately 900 km, where the Philippine Plate converges under the Eurasian Plate. The tectonic stresses accumulated in the area could cause a mega-earthquake approximately once every 100 to 150 years.according to estimates.
Previously, the Japanese government had predicted a 70-80% chance of it happening. an 8 to 9 magnitude earthquake along the trench within the next 30 yearsand a 2012 estimate shows the death toll could reach as high as 323,000.
What are earthquakes and why do they occur?
In 2017, the Japanese meteorological agency began operating a special information system on the seismic activity of the Nankai Trough, which is activated when an earthquake of magnitude 6.8 or greater hits areas where megathrust earthquakes are forecast or when unusual crustal movements are observed at plate boundaries.
The most recent earthquake originating in the Nankai Trough occurred in 1946, when an 8.0 magnitude earthquake triggered a tsunami with waves of almost 7 metres and left more than 1,300 dead.
Why do so many earthquakes occur in Japan?
Japan is recognized as one of the most seismically active countries in the world and the key to this frequent activity lies in the country’s geographical location, settled in the “Ring of Fire” or “Ring of Fire” of the Pacific.
The Pacific Ring of Fire is a vast and prominent horseshoe-shaped geological zone that stretches for about 40,000 kilometers along the coasts of the Pacific Ocean. This belt is famous for its intense seismic and volcanic activity, hosting approximately 75% of the world’s active volcanoes and being the scene of around 90% of the planet’s earthquakes.
Is it possible to predict an earthquake?
So far, scientists have not found a way to predict an earthquake. There are several studies that have sought to obtain a predictive tool, but they have not been fruitful. They have only succeeded in geographically delimiting dangerous seismic zones, That is, those places with the highest probability of an earthquake occurring..
There is also no exact answer to whether the weather or certain animals can prevent the earthquake.Although there is some evidence in this regard, there is still no affirmative or negative answer to this question.
However, a recent study from the Massachusetts Institute of Technology (MIT) suggests that Extreme weather events such as heavy snow and rain They could also play an important role in triggering some earthquakes.
The study, published in the journal Science Advancesindicates that episodes of heavy snow and rain contributed to a series of recent earthquakes in northern Japan. This research is pioneering in demonstrating that weather conditions can trigger some earthquakes..
According to the researchers, snow accumulation and other environmental loads on the surface affect the subsurface stress state, and the timing of intense precipitation events is well correlated with the onset of this earthquake chain.
Although this study opens a new chapter in the understanding of earthquakes, it is crucial to remember that Accurate earthquake prediction remains a challenge that science has yet to overcome..
