Counts of occurrence per depth in 釧路地方中南部

Counts of occurrence per depth in 釧路地方中南部 (Central Southern Kushiro region)  is shown as below graph, 

1km (red)…This count of the earthquakes is the 1st one. Most of them are the unknown details (with no data of magnitude) in 1919-1994. The ratio is 602/733=82%, all of them except 5 times in 1994 was occurred in 1919-1980, and there was the longest silent term between 1980-1994 (14 years).  After one more long silent term in 1994-2002, the counts has start gradual increasing again. The max magnitude is M6.1 in 1938.

50km(light blue) …The count is the 2nd. 2 times of M7 made it increase rapidly. One was M7.2 in 1961, and other was M7.2 in 2004. 

60km(blue)…The count is the 3rd as same as 90km/100km. These concentration of curves may mean the sign of some big earthquake around 50km or so on.

90km(brown)…The count is also the 3rd. The curve caught up in 2023, and has stopped the increase. The max magnitude is M6.3 in 1953. 

100km(gray)…The count is also the 3rd. M7.5 in 1993 made it increase rapidly. The curve overtook 50km at one time between 1996-2004. It seems that M7.5 of 100km in 1993 spread to M7.1 of 50km in 2004. The last occurrence was Sep/2024. The max magnitude is M6.3 in 1953.

10km(yellow)…The count is the 6th. The count increased by M6.3 in 1953, and overtook 50km's curve. Since then, these curves chased each other until 1977. The max magnitude is M6.5 in 1967.

80km …The count is also the 6th. The max magnitude is M6.0 in 1928. Since then, there has increased gradually.

120km/110km(gray)…The count is the 8th/9th. Since about 1961, these curves were twisting.  The each max magnitude is M6.3 in 1999/M5.8 in 1944. The bigger max magnitude, the count may increase more in the end. So, 110km may overtake 120km soon.

40km(green)…The count is the 10th. On addition to it, the last occurrence was in 2012. The max magnitude is M5.4 in 1987. 

70km(purple)…The count is the 11th. The max magnitude is M6.3 in 1927.

130km(gray)…The count is the 12th. The max magnitude is M5.8 in 2007.

30km(yellow green)…The count is the 13th. The max magnitude is M6.1 in 1959.The count should become higher. It will become higher in future.

20km(orange)…The count is the 14th. The max magnitude is M5.7 in 1967. The count may become higher in future.