Counts of occurrence per depth in 静岡県中部・西部地方

Counts of occurrence per depth in 静岡県中部・西部地方 (Central & Western region, Shizuoka Pref.)  is shown as below graph,

Because of the long silent terms since 1971, 1km curve was overtaken by 10km-30km curves. 40km/50km curves are following behind them. Similar counts are observed between the start count 131 of 1km of the longest silent term in 1953 and the count 130 of twin junction between 10km/20km in 2007.  The other similar counts of the largest ones of 40km/50km are 53 of M6.1 in 1965/ 51 of M5.9.  

• 1km (red)…The count is the 4th. Until being overtaken by 20km curve in 2009, the count was increasing steadily and keeping the 1st. Between 1944-1945, there was a rapid increase of 1km affected by M6.8 of 10km in Aichi Pref. (outside of this area). The 1km count increased from 74 to 97 before and after the M6.8. Then, the longest silent term was updated as the term between 1953-1956 (count as 131-132). Then, the silent terms became shorter temporarily, and then became longer again. The record breaking of the silent term length often occurred since 1971. During them, 20km curve overtook 1km curve, and 30km/40km curves followed them in later years. The longest silent term of 1km is between 2007-2024 (count as 186-187). The largest one is M5.8 in 1931. The largest one of 1km is M5.8 in 1931. 
• 10km(yellow)⋯The count is the 2nd.  Before M6.4 of 10km in 1935, there were the 3rd/2nd longest silent terms. So, 10km curve was following behind 1km curve with delay. On the other hand, because of too many long silent terms of 1km there were. After the M6.4 of 10km, the count of 10km increased steadily. But, 20km count was accelerated since the twin junction of 10km/20km with the count of 130 in 2007. 10km curve has been delayed from 20km though overtaking 1km curve. The largest one of 10km is the M6.4 in 1935.
• 20km(orange)⋯The count is the 1st. Until around 1975, 20km/30km curves were chasing each other back and forth, and they were following behind 10km curve. After  that, 10km curve joined their chase. As described above, 20km count was accelerated since the twin junction of 10km/20km in 2007. The largest one of 20km is the M6.5 in 2005 as count 168.
• 30km(yellow green)⋯The count is the 3rd. After the chase with 20km curve, 30km curve was also overtaken by 10km in 2011 (as count 156).  The largest one of 30km is the M6.1 in 1965 as the count 53. 
• 40km(green)⋯The count is the 5th. 40km curve is following behind 30km curve. The largest one of 40km is M5.9 in 1997 as the count 51. There was the rapid increase as the aftershocks as the count 51-58. 
• 50km(light blue)⋯The count is the 6th. 50km curve is following behind 40km curve. The count of 50km was accelerated by the M5.9 of 40km in 1997. The largest one of 50km is M5.6 in 1935.
• others⋯omitted.