Counts of occurrence per depth in 山梨県・富士五湖

Counts of occurrence per depth  in 山梨県・富士五湖（Yamanashi Pref. & Fuji Five Lakes area）is shown as below graph,  

M7.9 Great Kanto Earthquake induced the rapid increase of 1-30km in1923. Especially, 1km curve increased rapidly. But, 20km/10km curves increased steadily after the increases in 1923. The start/end points of the rapid increase seems to effect the other start/end points of other depths.

 

• 20km (orange)…The count is the 1st. M7.9 of 20km was occurred in Western Kanagawa in 1923. The M7.9 was named as "Great Kanto Earthquake", ant it is the greatest one of all depths. It was occurred on the triple junction of 10km/20km/30km curves. It means it was occurred at the same count of them as count 5. The M7.9 was induced the rapid increases of 1km-30km. After them, 20km curve increased steadily.  count has been increasing steadily. During the longest silent term, 20km curve overtook 1km curve in 1996. After the overtaking, 20km curve accelerated in 1996. It was also accelerated by M9.0 Great East Japan Earthquake in 2011. 
• 10km (yellow)…The count is the 2nd. There were 3 major rapid increases of 10km curve. The first one was occurred by the M7.9 of 20km in 1923, and 20km curve increased steadily until 1928. Since 1928, there was the 2nd longest term of 10km at that time between 1928-1930. Just after it, the next major rapid increase of 10km was occurred in 1930. It was induced by M7.3 of 1km in Northern Izu in 1930. By this increase, 10km curve overtook between 1930-1950 temporary. After overtaken by 20km again, the silent terms of 10km became longer. The longest one of 10km is 1979-1983. Then, the silent terms become shorter again gradually until 2011. The latest major rapid increase of 10km was induced by M9.0 Great East Japan Earthquake. Though the gap between 20km and 10km curves became smaller, 10km curve is still following behind 20km curve. The largest one of 10km is M6.4 in 2011.
• 1km(red)⋯The count is the 3rd. There were the rapid increase of 1km curve caused by the M7.9 of 20km in 1923. M6.8 was occurred as the first aftershocks in 1923, and is the largest one of 1km (The epicenter is outside of this area). Then, 1km curve has been increased step by step until 2020. The 1st longest silent term is updated as between 1983-1994. During it, 1km curve was overtaken by 20km.  Furthermore, it was also overtaken by 10km curve in 2011. 
• 30km(green)⋯The count is the 4th. There was the rapid increase by the M7.9 of 20km. Then, there was  a continueing earthquakes of 30km in 1939. The cause is unknown. The end's count of 30km was 35. This count is near the count of 1km at M7.3 in 1924. The 1km count was accelerated by the M7.3. 10km's overtaking point was count 33, ant it was also near the count of 30km's end count. The longest silent term of 20km was between 1943 - 1947, and the count was between 67-68. On the other hand, there was the long silent term of 30km, and the count was between 66-67. They were very near. The acceleration start of 30km count curve between 84-90 in 1988 corresponds with the acceleration end of 1km count curve between 66-81 in 1930. The latest occurence of 30km is in 2025 as 132 count. It's near the start count of 20km in 1976 as 135. 30km curve might have the rapid increase when the count goes over 135. The largest one of 30km is M5.9 in 1931.
• others⋯omitted.