During the 10 years from 2011, when the Great East Japan Earthquake occurred, to last year, the number of earthquakes observed in the aftershock area of ​​the huge earthquake off the coast of Tohoku has tripled compared to the 10 years before the earthquake.

Looking at the number by year, it has been declining gradually year by year since the great earthquake, but it is still higher than before the earthquake, and the Japan Meteorological Agency is calling for caution in the future.

According to the Japan Meteorological Agency, the number of earthquakes observed in the aftershock area of ​​the huge earthquake off the coast of Tohoku was 570,207 during the 10 years from 2011 when the Great East Japan Earthquake occurred to last year.



This means that the number of earthquakes observed in the 10 years up to 2010 before the earthquake, which is 188,766, has tripled.

Looking at the number of earthquakes with a magnitude of 5 or more, there were 1012 occurrences in the 10 years up to last year, which is about five times higher than the 10 years before the earthquake.



Looking at the number of earthquakes since 2011 by year, the number of earthquakes was 135,794 in 2011, when a huge earthquake occurred, but since 2012, it has been increasing and decreasing gradually, and it has been gradually decreasing last year. , 48,438 times.



Compared to 2011, it has decreased by nearly 90,000 times, but it continues to be higher than the average annual number of 18,876 times in the 10 years up to the year before the earthquake.



In the area along the "Japan Trench" from Tohoku to the offshore of Kanto where a huge earthquake occurred 10 years ago, it is evaluated that a large earthquake with a magnitude of 7 or more will continue to occur with a high probability, and the Japan Meteorological Agency is calling attention. I will.



Noriko Kamaya, Earthquake Information Planning Officer of the Japan Meteorological Agency, said, "Although the aftershock activity of the huge earthquake is decreasing in the big picture, there are occasional big earthquakes like the earthquake off Fukushima prefecture last month. Is expected to continue for a long time, and I would like you to pay close attention to seismic activity. "

The number of earthquakes nationwide exceeds about 1.7 times

During the 10 years from 2011 to last year when the Great East Japan Earthquake occurred, the number of earthquakes that occurred all over the country was also due to the effects of the huge earthquake off the coast of Tohoku that caused the earthquake and the 2016 Kumamoto earthquake, before the earthquake. It exceeded the 10 years up to the year by about 1.7 times.

According to the Japan Meteorological Agency, the number of earthquakes that occurred in and around the Japanese archipelago during the 10 years from 2011 to last year was 2,051,547.



Compared to 1,237,312 times in the 10 years up to 2010 before the earthquake, it increased by 814,235 times, about 1.7 times more.



Looking at the number by year, ▽ the largest number of earthquakes occurred in 2011 was 303,824 times, ▽ 2016 was 286,406 times, ▽ 2017 was 269,428 times, ▽ 2018 was 221847 times. And so on.



Of these, the Kumamoto earthquake occurred in 2016, and the Hokkaido Eastern Iburi Earthquake occurred in 2018.

Looking at the number of earthquakes with a magnitude of 5 or more, there were 2065 earthquakes in the 10 years up to last year, 1.3 times more than in the 10 years before the earthquake.



Looking at the changes in the number of earthquakes since 2011, it has been on a gradual downward trend since the occurrence of the great earthquake, but occasionally it has reached the number close to 2011 in some years.



The number of earthquakes last year was 213,358, which is a decrease of more than 90,000 compared to 2011, but it continues to be compared with the average annual number of 123,731 in the 10 years until the year before the earthquake. It is in a lot of states.