Counts of occurrence per depth in 北見・紋別地方

Counts of occurrence per depth in 北見・紋別地方 (Kitama & Monbetsu region) is shown as below graph,

Colored labels show the data of Max Magnitude/depth/date/count per each depth.

There was only data of 1km before M5.1 (190km) in 1944. After the M5.1, the max Magnitude of all data had been broken the record of them as below,

• Max=M4.9 (  1 km) : 1919-1944
• Max=M5.1 (190km) : 1944-1966
• Max=M5.2 (250km) : 1966-1990
• Max=M5.4 (170km) : 1990-2025

10km (count=1) was occurred in 2007 after M5.4 (170km/count=1) and 170km (count=2) about 2 years later. 10km (count=2-9) was occurred in 2009 including M4.2 (10km/count=4, max of 1km). At the count=5 of 10km, it became the same one of 1 km. The common count may be the trigger timing of the rapid increase of 10km. After 2 long silent times of 4 years/5 years, the count of 10km increased rapidly again in 2023.  

Since of no record update in 1km there has been, M4.9 is still the max value in 1km data. 3 months later, the 2nd longest silent term of 1km finished by the count =6 of 1 km. After the 1st longest silent term (1926-1976) and the 2nd one (1976-2024), there might be occurred the rapid increase of 1km's count in the near future.