Analysis for the Area chart of epicenter(Magnitude)-1

Most of earthquakes in the same area is single per day unless after big ones. So,the sum of magnitude per day can show the activity level in the area even though the values themselves have no meaning. Furthermore, by separating the sum per the depth class, it can show which depth is more active also. I defined the sum as "Accumulated value" of magnitude, and separate it per depth class(1km,10km,etc.).

I show will show the "Accumulated value Chart" for 10 major earthquakes after 2000 year. The first one is for Noto Peninsula Earthquake in 2024 (and The Noto Hanto Earthquake in 2007) as below,

There are more red (1km) and yellow (10km) area, especially after M7.6/M6.9. There are remarkable red area before them also, and there are long silent terms before the signs. It means red area (1km) may be the previous sign to great magnitude earthquakes.

The next chart is for Hokkaido Eastern Iburi Earthquake in 2018 as below,

There was a big peak of red area related with Eruption of M’t Usu in 2000 before the peak of the Iburi Earthquake(M6.7) in 2018. There was a long silent term (2003-2010) of red area (1km depth) also. After the silent term, there was middle peak of red area in 2014. As the epicenter of M6.7 was 37km, there was no peak of red area just after it. But, red area occurrence had great effect to M6.7.  

The 3rd chart is for Kumamoto Earthquake (M7.3) in 2016. As same as in Noto, there are much red area (1km) and yellow area (10km) totally. There were middle  peaks of red in 1975 and yellow in 2000. In 1990, Fugendake was erupted in 1991. As same as Kumamoto Earthquake,  eruption seems to have deep relationship with earthquake.

The 4th chart is for Great East Japan Earthquake(M9.0) in 2011 as below,

There are many peaks of big earthquakes more than 10 times of over M7. "Accumulated value" of magnitude per depth are added on in descending order of depth. The reason why is that less depth is more frequent and more important for the check of the activity level. As the total value itself has no great meaning, the vertical axis value is cut by 50[M]. Horizontal axis is non-liner.