Counts of occurrence per depth in 青森県東方沖

Counts of occurrence per depth in 青森県東方沖 (Eastern offshore of Aomori Pref.） is shown as below graph,

1km curve has stopped with the 1st longest silent term in this mohth. During the long silent term, 60km curve overtook 1km curve. Not only 60km curve, but also 60km / 70km / 50km / 30km / 40km /20km /10km curves is following behind 1km curve since the septet junction among 10km-70km curves just after M7.9 of 1km in 1968. The M7.9 is the greatest one of all depths. The M7.9 is worried if it may become  the trigger of the huge called as "Off the Coast of Hokkaido and Sanriku Subsequent Earthquake Advisory".

By using a chart that includes such multi-junctions, it may be possible to predict the occurrence count of main aftershocks. This can be achieved by identifying the number of junctions where the cumulative frequency curves of different depths intersect during a rapid increase.

1km(red)⋯ The count is the 2nd. There was the 4th longest silent term of 1km between 1927-1929 (count as 1213). There were both the 7th/9th longest silent term between 1931- 1933 (count as 18-19)/ 1934-1936 (count as 22-23). After these long silent terms, each count increased with a steep slope. There was a rapid increase of 1km caused by M7.9 of 1km (count as 247) in 1968. The M7.9 is the greatest one of all depths.  The silent terms became longer and longer. There was the longest silent term between 1998-2025 (count as 333-334  this month). Because of the longest one, 1km was overtaken by 60km curve.

60km (blue)⋯The count is the 1st. The count of 60km increased steadily until 1967. M7.5 of 10km occurred as the start point of septet junction among 10km-70km curves. The rapid increase of 60km started at count 64 before the M7.5 six hours ago. After the rapid increase, the count of 60km has been increasing steadily again, and overtook 1km curve during the longest silent term of 1km. The largest one of 60km is M7.1 in 1945 (count as 12).

70km(purple)⋯The count is the 3rd. 70km/60km curves were overtaking and being overtaken before 1968. After the rapid increases by the M7.5 of 10km, 70km curve was following behind 60km curve. The largest one of 70km is M6.6 of 1945 (count as 50).

50km (light blue)⋯The count is the 4th. There were the 1st/2nd longest silent terms between 1930-1934  (count as 9-10)/1936-1939 (count as 12-13). After each long silent term, the count increased with a steep slope. Furthermore, there was also the 3rd longest silent term between 1944-1946 (count as 22-23).  50km curve was caught up with by 70km curve  in 1950s, and was overtaken. After the rapid increase of 50km on the septet junction among 10km-70km curves in 1968, 50km/70km curves overtook and were overtaken until  around 1990. But, after that, 50km curve was overtaken by 70km curve again even though there was M7.0 of 50km in 1971 (count as 84). The largest one of 50km is M7.5 in 2025 (count as 289 updated 6 days ago). The count has been increased rapidly by the aftershocks of the M7.5 from count 287 to 293 (until 2025/12/10).

30km (yellow green)⋯The count is the 5th. 30km curve is following behind 1km curve. There were 3 major longest silent terms of the 2nd/4th/3rd before the M7.5 of 10km on the septet junction among 10km-70km curves in 1968.The 2nd one was between 1926-1930 (count as 3-4). The 4th one was between 1932-1936 (count as 7-8). The 3rd was between 1936-1940 (count as 8-9). After that, the count of 30km increased with a steep slope steadily until 1968. In 1968, the M7.9 of 10km occurred, and it induced the rapid increase of 30km (count as 49-70). After that, the count of 30km is increasing similarly to the 50km curve. The largest one of 30km is M6.8 in 1922(count as 2).

40km (green)⋯The count is the 6th. 40km curve is following behind 10km curve before the M7.5 of 10km on the septet junction among 10km-70km curves in 1968. M6.8 of 30km occurred in 1922.  The 2nd longest silent term was between 1923-1927 (count as 2-3). At the start point of the silent term, M6.2 of 40km occurred in 1923. The 2nd one of 40km was covered with the 2nd one of 30km. The 1st one of 40km was between 1934-1938 (count as 12-13).   After the sequential earthquakes of M6.3/M6.2 of 40km in 1944/1945 (count as 21-22), there was a rapid increase in 1945 until M6.6 of 40km (count as 26) . About 80 days later, there was the next rapid increase in 1945 (count as 27-31). Then, silent terms became longer until 1968. The main rapid increase (count as 64-78) occurred at the septet junction among 10km-70km curves just after M7.9 of 1km. After that, 40km curve is increasing behind 50km curve. The largest one of 40km is the M6.6 in 1945.

20km(orange)⋯The count is the 7th. After the sequential longest silent terms of the 2nd/3rd/4th/6th between 1920-1939 (count as 3-7), there was a rapid increase of 20km in 1943 (count as 12-15). Then, the silent terms became long again. The main rapid  increase count as 44-70) occurred at the septet junction among 10km-70km curves just after M7.9 of 1km in 1968. After that, 20km curve increases behind 30km curve. The 1st longest silent tem was between 1977-1994 (count as 99-100). The largest one of 20km is M7.1 in 1943 (count as 12).

10km(yellow)⋯The count is the 8th. 10km curve is following behind 1km curve. Until  the septet junction among 10km-70km curves just after M7.9 of 1km in 1968, 10km curve was following almost keeping the count rank as the 2nd or 3rd. After that, the silent terms became long. The 1st/2nd one was between 1978-1997 (count as 101-102)/2019-2025 (count as 118-not yet). The 2nd longest one of 10km is almost covered by the 1st one of 1km between 1998-2025. The largest one of 10km is M7.5 in 1968 (count as 72).

others⋯omitted.