Analysis for the chart of maximun Magnitude per the depth of epicenter (Dragon Chart)

 For the analysis for discrete values, class hierarchy is very useful,especially, in earthquake analysis. Because earthquake is phenomenon occurred in the stacked different layers.

The plotted chart of maximum magnitude per the depth level in Sanriku-oki Area including of Great East Japan Earthquake (M9.0) is as below, 

These 2 plots are for before/after Great East Japan Earthquake. The plots with black line is before it (1919 -2011).  The red line with inclination of 1.00 . The other with blue line is after (2011-2024). For each plots, approximate straight line is added. The maximum magnitude of M9.0 is classified as 20km (orange) depth class because of the value of 24 km. The black plot line has almost no looseness with almost 1.00 inclination. I believe it must have special meaning to be almost 1.00. There was a shrinkage between plots between of 10 km/20km. The depth of M9.0 was 24 km. As the shrinkage depth is near to 24 km, there might have some meaning also.   

Deep depth class (100km & 120km) lie down on the grand line because of the frequency as only 1 time (Ln (1) =0). To be surprised, like as M8 level huge earthquakes are not rare in general. So, sometimes, the maximum magnitude rises up on the vertical axis against the shallower plots. According with shallower depth, the frequency of the maximum magnitude show the tendency rising up higher. It seems to be the reflection of Gutenberg–Richter law.  

The next plotted chart is for in Tokachi-oki Area (1919-2024) is as below,

The plot line twists right and left. It looks like twisting dragon(or snake). Especially, the plot line of in Sanriku-oki just before M9.0 in 2011 looks like rising dragon to sky straightly. These are the reason why I named this plot chart as "Dragon Chart".