Counts of occurrence per depth in 岐阜県飛騨地方

Counts of occurrence per depth in 岐阜県飛騨地方 (Hida region, Gifu Pref.) is shown as below graph,

The count of 10km is the 1st, and it is increasing steadily still now. As the greatest one of all depths, M6.8 of 1km occurred in 1984. These graphs graph behaviors are similar to the ones in  長野県南部  (Southern Nagano Pref.) because of the overlapping area. The most difference is less counts of 30km-50km than ones in  長野県南部  (Southern Nagano Pref.) 

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• 10km (yellow)…The count is the 1st. There were 3 major rapid increases of 10km count after the longest silent term between 1919-1925. The 1st rapid increase was by M6.6 of 1km in 1969. The 2nd one was by M6.8 of 1km in 1984. The 3rd one was a shallow earthquake swarm in 1998. After the 3rd one, 10km curve overtook 1km curve. And the count of 1km is increasing with the steep slope. The largest one of 10km is M6.2 of 10km induced by the M6.8 of 1km in 1984.
• 1km (red)…The count is the 2nd. As similar to 10km curve, there were 2 major rapid increases of 1km count in 1969/1998. But, the silent terms of 1km became longer and longer after 1969. The longest one of 1km was between 1986-1993.  After the longest one of 1km, 1km curve was overtaken by 10km curve. Even though the M6.8 of 1km in 1984 was the greatest one of all depths, there was almost no aftershock of 1km againt the many ones of 10km.  
• 20km(orange)⋯The count is the 3rd. There was a rapid increase between count 14-28 of 20km in 1969 induced by the M6.6 of 1km on the same day. After the M6.6 of 1km, the silent terms of 20km became longer rapidly.  The longest silent term of 20km is between 1988-2011.  The end count 28 of the rapid increase of 10km is near to the end count 26 of the 3rd longest silent term of 1km between 1946-1951 (count 25-26). The largest one of 20km is M4.9 in 1969.  
•  others⋯ As remarkable ones of others, there were M6.6 of 250km in 1931/M6.0 of 260km in 1954.