Counts of occurrence per depth in 苫小牧沖

Counts of occurrence per depth in 苫小牧沖 (Tomakomai offshore region) is shown as below graph,  

30km/40km increased rapidly by the aftershocks of M6.7 in 2018 (Hokkaido Eastern Iburi Earthquake). The epicenter is located outside of the northeast corner of this area. The largest earthquakes are 2 times of M6.3, and they are included by 140km (only 4 counts).

• 30km(yellow green)…The count is the 1st. Before Hokkaido Eastern Iburi Earthquake M6.7 of 40km in 2018, the count was 10th.  The aftershocks rose up the counts of 30km/40km/others even though the epicenter was out of this area (nearby the northeast corner of this area). They were caused of the junctions both triple of 40km/30km/20km and quartet of 100km/40km/30km/ 10km. In the triple junction, 30km had the largest aftershock as M5.5.  The M5.5 is also the largest one of 30km. 
• 40km(green)…The count is the 2nd. The count also rose up rapidly by the M6.7 of 40km in 2018 (Hokkaido Eastern Iburi Earthquake). The largest one is M5.4 in 1920. 
• 1km(red)…The count is the 3rd. The count increased after both M5.6 of 100km in 1931 and M6.3 of 140km in 1945. Then, the silent term became longer. The longest silent term is between 1974 and 1995. After 2 more long silent terms, there was the rapid increase of M5.6 of 1km in 2014. The M5.6 is the largest one of 1km. There was 3 years silent term between 2014-2017 before the M6.7 in 2018 (Hokkaido Eastern Iburi Earthquake). It seems to be one of sign of the M6.7 1 years ago. 
• 70km(purple)…The count is the 4th. Around 1957-1958, 60km/70km/120km /130km curves concentrated on a place. After it, 3 continuous counts was occurred in 1960. Next, there was the longest silent term between 1960-1988. In result, 100km curve caught up with 70km. After it, 70km curve slope became steep. The increase has stopped since 2021 as same as 1km. The largest of 70km is M5.8 in 1941.     
• 130km(gray)…The count is the 5th.Though there was the longest silent term between 1974-1992, the curve increased gradually. It stopped after the overtaking 60km in 2025 after 7 years silent term since the aftershock of the M6.7 in 2018 (Hokkaido Eastern Iburi Earthquake) . The largest of 130km is M5.3 in 1934.     
• 60km(blue)…The count is the 6th. After the 3rd/2nd longest silent terms, the count increased gradually. Around 1995, the silent term became longer. The longest silent term is between 2010-2021. Then, the curve became steep again. The largest of 60km is M5.3 in 1990.       
• 90km（brown）…The count is the 7th. After the longest silent term between 1954-1988, the curve became steeper. 3 years ago of the M6.7 in 2018 (Hokkaido Eastern Iburi Earthquake), the silent time became longer suddenly. The silent term was continued until 2021. It seems one of the sign of the M6.7. Then, the curve became steep again. The largest of 90km is M5.2 in 1937. 
• 10km(yellow)…The count is the 8th. After M6.3 of 140km in 1945, 1km increased rapidly. On the other hand, 10km increased slightly. And the longest silent term between 1949-1998 was occurred. Then, the curve became steep again. The largest of 10km is M5.3 in 1930.     
• 140km(gray)…The count is only 4 times. But, 4 earthquakes includes 2 times of M6.3 in 1945/1975, and M6.2 in 2023. M6.3 is the greatest magnitude of all depths.
• others…omitted. 

MD-T chart in 苫小牧沖

MD-T chart in 苫小牧沖 (Tomakomai offshore region) 

 

MD chart in 苫小牧沖

MD chart in 苫小牧沖 (Tomakomai offshore region) 

 

Dragon chart in 苫小牧沖

Dragon chart in 苫小牧沖 (Tomakomai offshore region) 

30km/50km/60km/130km are located in a straight line. 20km/70km/120 are also located in a straight line.(orange kines)
 

Sum of Magnitude per 1day in 苫小牧沖

Sum of Magnitude per 1day in 苫小牧沖 (Tomakomai offshore region) 

note : Horizontal axis isn't linear.
 

Distribution of Magnitude in 苫小牧沖

Distribution of Magnitude in 苫小牧沖 (Tomakomai offshore region) 

 

Distribution of Depth in 苫小牧沖

Distribution of Depth in 苫小牧沖 (Tomakomai offshore region)  

 

 

Area map of 苫小牧沖

Area map of 苫小牧沖（Tomakomai offshore region）is defined for epicenter's analysis as below, 

Counts of occurrence per depth in 浦河沖

Counts of occurrence per depth in 浦河沖 (Urakawa offshore region) is shown as below graph, 

M7.1 of 40km is the greatest one of all depths, and was occurred the double junction of 40km/30km in 1982. The M7.1 induced not only the rapid increases of 40km / 30km / 20km, but also the sequential 2nd/1st longest silent terms of 1km. In result, 60km/70km/50km curves have overtaken 1km.     

• 60km(blue)…This count is the 1st. 60km/70km have been overtaking and being overtaken. After overtaking 1km, both of 60km/70km almost overlapped. The largest magnitude of 60km is M6.7 in 1970. 
• 70km(purple)…This count is the 2nd. The largest magnitude of 70km is M6.9 in 1932.   
• 50km(light blue)…This count is the 3rd. After M7.1 of 40km in 1982, the curve rose up around 2004. The largest magnitude of 50km is M6.8 in 1968.
• 1km(red)…This count is the 4th. There was the 2nd longest silent term between 1982-1995. Continuously, the 1st longest one was occurred between 1995-2011. After them, the silent term is becoming longer. The largest magnitude of 1km is M6.8 in 1944.  
• 40km(green)…This count is the 5th. M7.1 was occurred at the double junction of 40km/30km curves in 1982. The M7.1 is the greatest one of all depths. 
• 30km(yellow green)…This count is the 6th. The 30km curve follows the 40km with the similar pattern.The largest magnitude of 30km is M6.8 in 1931.
• 10km(yellow)…This count is the 7th. 10km/90km have been overtaking and being overtaken. The rapid increase was occurred after M5.1 of 10km in 2011. By the aftershocks of M5.1, the longest silent term of 1km since 1995 was interrupted, and the curve overtook 20km/80km curves. The largest magnitude of 10km is M6.0 in 1937.  
• 20km(orange)…This count is the 8th. The curve followed 40km/30km. As same as them, there were 2 major rapid increases as the aftershocks both of M6.8 in 1968 of 50km and of M7.1 of 40km in 1982.  The largest magnitude of 20km is M5.7 in 1942. 
• Others…omitted. 

MD-T chart in 浦河沖

 MD-T chart in 浦河沖 (Urakawa offshore region) 

 

MD chart in 浦河沖

MD chart in 浦河沖 (Urakawa offshore region) 

 

Dragon chart in 浦河沖

Dragon chart in 浦河沖 (Urakawa offshore region) 

 

Sum of Magnitude per 1day in 浦河沖

Sum of Magnitude per 1day in 浦河沖 (Urakawa offshore region) 

note : Horizontal axis isn't linear.
 

Distribution of Magnitude in 浦河沖

Distribution of Magnitude in 浦河沖 (Urakawa offshore region) 

 

Distribution of Depth in 浦河沖

Distribution of Depth in 浦河沖 (Urakawa offshore region) 

 

Area map of 浦河沖

Area map of 浦河沖 (Urakawa offshore region) is defined for epicenter's analysis as below, 

 

Counts of occurrence per depth in 十勝沖

 Counts of occurrence per depth in 十勝沖 (Tokachi offshore region) is shown as below graph,  

The count of 1km has been down from the 1st to 5th after the longest silent term between 1978 - 2024. On the other hand, 50km's count has been up to the 1st. M8.1 of 50km was occurred at the triple junction of 50km/40km/10km. 6 days later, M6.9 of 70km was also occurred at the triple junction of 70km/80km/60km. The M8.1 is the greatest one of all depths (1km's one is only M6.3). M8.1 may be transferred to 1km by domino effect in some day. 

• 50km(light blue)…This count is the 1st. 50km/40km have been overtaking and being overtaken.As 40km overtook had long silent term between 1942 - 1948, 50km overtook 40km. Then, by M8.2 of 50km in 1952, 40km had more aftershocks and overtook 50km again. Later, 50km caught up with 40km by M7.0 of 50km in 1971. Around 1986, the become more steep, and 1km went into the longest silent term. So, the curve becomes top. The greatest earthquake of all depth is M8.2 of 50km in 1952. The M8.2 was occurred at the triple junction of 50km/40km/10km. 6 days later, M6.9 of 70km was also occurred at the triple junction of 70km/80km/60km. 
• 40km(green)…This count is the 2nd. As described above, 50km/40km have been overtaking and being overtaken. But, the largest magnitude of 40km is M6.9 in 1961 (far less than M8.2 of 50km). The count doesn't reach to 50km. 
• 60km(blue)…This count is the 3rd. The count has been increased smoothly.  The largest magnitude of 60km is M6.4 in 1943. 
• 30km(yellow green)…This count is the 4th. 30km/20km had the double junction at M7.1 of 20km in 2003. The count jumped up after the M7.1 on the same count with 20km. The largest magnitude of 60km is M7.1 in 2008. 
• 1km(red)…This count is the 5th. There was the longest silent term between 1978 - 2024. Before it, the count was the 1st. The largest magnitude of 1km is M6.3 in 1926.   
• 70km(purple)…This count is the 6th. As described above, M6.9 of 70km was occurred at the triple junction of 70km/80km/60km in 1952. M7.1 was occurred the next count became the same as 30km after the long silent term of 30km. The largest magnitude of 60km is M7.1 of the triple junction in 1962.   
• 20km(orange)…This count is the 7th. M7.1 was occurred at the double junction of 20km/30km in 2003. The M7.1 is the greatest magnitude of 20km. After 2021, the curve slope has become steep. So, there is a possibility of the rapid increase in near future. 
• 80km(navy)… This count is the 8th. There was a steep slope increase around M7.1 of 70km in 1962. The largest magnitude of 80km is M6.4 in 1983. 
• 100km(gray)… This count is the 9th.The largest magnitude of 100km is M5.6 in 1926. 
• 10km(yellow)… This count is the 10th. In past, it was 4th after M8. 2 of 50km for a time. But, the silent terms became longer. The largest magnitude of 10km is M6.7 in 1936. 
• others…omitted.

MD-T chart in 十勝沖

MD-T chart in 十勝沖 (Tokachi offshore region)

Since 1977, MD value has reached to the level under 10. It seems the earthquakes may become to activate.
 

MD chart in 十勝沖

MD chart in 十勝沖 (Tokachi offshore region) 

 

Dragon chart in 十勝沖

Dragon chart in 十勝沖 (Tokachi offshore region)

These plots seem to be random at first glance. There are some plots a straight line (orange lines). For example, the combinations of 60km/1km/130km/90km/120km, 20km/70km/30km(=M7.1), 50km/40km/60km, 50km/70km/80km,and 80km/130km/140km are in a straight line. 

Sum of Magnitude per 1day in 十勝沖

Sum of Magnitude per 1day  in 十勝沖 (Tokachi offshore region)

note : Horizontal axis isn't linear.
  

Distribution of Magnitude in 十勝沖

Distribution of Magnitude  in 十勝沖 (Tokachi offshore region)

 

Distribution of Depth in 十勝沖

Distribution of Depth in 十勝沖 (Tokachi offshore region)

 

Area map of 十勝沖

Area map of 十勝沖 (Tokachi offshore region) is defined for epicenter's analysis as below, 

 

Counts of occurrence per depth in 釧路沖

 Counts of occurrence per depth in 釧路沖 (Kushiro offshore region) is shown as below graph, 

Though 1km is the 1st count curve, after the longest silent term, no occurrence. M8.2 of 50km occurred around the quintet junction of 50km / 40km / 20km / 60km / 10km in 1952. M8.2 of 50km kept most of potential until M8.0 of 50km in 2003. On the other hand, M7.5 of 100km was caused by the quartet junction of 10km/70km/80km/100km in 1993. 50km curve has the steep slope. So, 50km may catch up with 1km in future. It may cause of the domino reaction with other(s). 

• 1km(red)…This count is the 1st. But, the longest silent term is continuing since 1994 after the 2nd longest one between 1980-1994. The rapid increase was just after M8.2 of 50km in 1952. The M8.2 of 50km is the greatest magnitude of all depths. The largest magnitude of 1km is M6.9 in 1935. 
• 50km(light blue)…This count is the 2nd. As described above, The greatest magnitude of 50km is M8.2 in 1952. The M8.2 was occurred around the quintet junction of the curves among 50km/40km/20km/60km/10km. After the M8.2, the count was accelerated by M7.2, and caught and overtook 40km around 1968. Since it, 50km/40km curves almost overlapped each other. M8.0 of 50km in 2003 seems to be the result of the combined earthquakes of 50km/40km kept the most energy of M8.2 in 1952. The curve is keeping the large slope. So, 50km may catch with 1km in future.
• 40km(green)…This count is the 3rd. The greatest magnitude is M7.4 in 1973. The M7.4 caused not only the combined rapid increases of 40km/50km, but also 30km/20km's ones as the aftershocks. The overlapped of 40km/50km almost continued until M8.0 of 50km in 2003. After it, 50km was accelerated by M7.1 of 50km in 2004. So, 40km curve lagged behind from 50km. 
• 60km(blue)…This count is the 4th. The curve shows the similar pattern with 50km with low level. In recent years, it almost overlapped with 30km. There were 2 major rapid increases by M7.4 of 40km in 1973/M8.0 of 50km in 2003. The largest magnitude is M7.1 in 2008. 
• 30km(yellow green)…This count is the 5th.The curve followed 60km. But, after M8.0 of 50km in 2003, the increase becomes slow down. The pattern of 30km/50km after the M8.0 resembles with the one of 40km/50km. The largest magnitude is M7.1 in 2008 after the slow down. 
• 20km(orange)…This count is the 6th. There was the entanglement among 10km/20km/30km/60km after M7.2 of 50km in 1961, and separated from each other after M7.4 of 40km in 1973. Later, 20km/10km had the longer silent terms including the longest silent term. Recently, the curve slopes of them have become steep a little bit. It might be the sign of more activity of them than before. The largest magnitude is M6.2 in 1921.
• 70km(purple)…This count is the 6th. 70km/80km curves were overtaking and being overtaken each other. 100km curve joined the entanglement of them after M7.5 of 100km in 1993 until about M7.1 of 30km in 2008. 70km curve become more steep, and caught up with 20km around in 2000. The largest magnitude is M6.3 in 1927.  
• 80km(navy)/100km(gray)…The count is the 7th/8th. After the  entanglement among 70km/80km/100km after M7.5 of 100km in 1993, 80km / 100km curves are still overlapped each other. The largest magnitude is M6.5 in 1949(80km)/M7.5 in 1993 (100km).  
• 90km(brown)…This count is the 9th. The the largest magnitude is M6.3 in 1953.  
• 10km(yellow)…This count is the 10th. The the largest magnitude is M7.1 in 2008. Because of these values, the potential seems to be high even the low ranking.
• others…omitted.

MD-T chart in 釧路沖

MD-T chart in 釧路沖 (Kushiro offshore region) 

  

MD chart in 釧路沖

 MD chart in 釧路沖 (Kushiro offshore region) 

 

Dragon chart in 釧路沖

 Dragon chart in 釧路沖 (Kushiro offshore region) 

  

Sum of Magnitude per 1day in 釧路沖

Sum of Magnitude per 1day in 釧路沖 (Kushiro offshore region) 

note : Horizontal axis isn't linear.
 

Distribution of Magnitude in 釧路沖

Distribution of Magnitude in 釧路沖 (Kushiro offshore region) 

 

Distribution of Depth in 釧路沖

Distribution of Depth in 釧路沖 (Kushiro offshore region) 

 

Area map of 釧路沖

Area map of 釧路沖 (Kushiro offshore region) is defined for epicenter's analysis as below, 

 

Counts of occurrence per depth in 根室半島南東沖

Counts of occurrence per depth in 根室半島南東沖 (Southeast offshore the Nemuro Peninsula) is shown as below graph, 

Though 1km is the 1st count curve, after the longest silent term, no occurrence. M7.4 of 40km occurred around the triple junction of 50km/40km/30km in 1973. After M7.4, these depths are keeping ranks between 2nd and 4th. On the other hand, shallow depths of 30km/20km/10km keeps lower ranks. Especially, even though 30km recorded M8.2 as the greatest one of all depths, 30km keeps the low rank. Such reversal status seems to be unstable with high stoked energy. 

•  1km(red)…This count is the 1st. The increase continued steady until 1982. After it, the silent term became longer and longer. The longest one is between 1994-2016, and there is no new earthquake after the last one still now. The the largest magnitude is M6.9 twice in 1925/in 1935. 
• 50km(light blue)…This count is the 2nd. The greatest magnitude of 50km is M7.1 in 1973. The M7.1 was occurred as the one of the aftershocks of M7.4 one week ago. There were 2 times of the major rapid increases when M7.4 of 40km in 1973/M8.2 of 30km in 1994. The count of 50km is still increasing now, and approaching to 1km.  
• 40km(green)…This count is the 3rd. The greatest magnitude is M7.4 in 1973. The M7.4 was occurred round the triple junction of  50km / 40km / 30km. After the rapid increase by the aftershocks, the curve got tangled with 50km. But, after M7.0 of 60km in 2000, 40km's increase becomes slow down.
• 60km(blue)…This count is the 4th. The curve shows the similar pattern with 50km with low level. In recent years, it almost overlapped with 30km. There were 2 major rapid increases by M7.4 of 40km in 1973/M8.2 of 30km in 1994. The the largest magnitude is M7.0 in 2000. 
• 30km(yellow green)…This count is the 5th.The curve followed 40km. But, after M7.4 of 40km in 1973, the increase becomes slow down around the the triple junction of 50km / 40km / 30km. After the long silent term between 1984 - 1988, the silent term becomes shorter again. Then, M8.2 was occurred in 1994. The M8.2 is the greatest one of all depths. After the M8.2, the silent term becomes longer now. So, 60km overtakes 30km now. 
• 70km(purple)…This count is the 6th. 70km overtook 20km around in 2015. The the largest magnitude is M6.3 in 1931.
• 20km(orange)…This count is the 7th. Though the curve almost overlapped with 60km before M8.2 of 30km in 1994, 20km became slow down against 60km rapid increase. The the largest magnitude is M6.2 in 1921.
• 80km(navy)…This count is the 8th. The the largest magnitude is M6.5 in 1949.
• 90km(brown)…This count is the 9th. The the largest magnitude is M6.2 in 1967.  
• others…omitted 

MD-T chart in 根室半島南東沖

MD-T chart in  根室半島南東沖 (Southeast offshore the Nemuro Peninsula)  

 

MD chart in 根室半島南東沖

MD chart in 根室半島南東沖 (Southeast offshore the Nemuro Peninsula) 

 

Dragon chart in 根室半島南東沖

 Dragon chart in  根室半島南東沖 (Southeast offshore the Nemuro Peninsula)  

 

Sum of Magnitude per 1day in 根室半島南東沖

 Sum of Magnitude per 1day in  根室半島南東沖 (Southeast offshore the Nemuro Peninsula)  

note : Horizontal axis isn't linear.
 

Distribution of Magnitude in 根室半島南東沖

Distribution of Magnitude in  根室半島南東沖 (Southeast offshore the Nemuro Peninsula) 

 

Distribution of Depth in 根室半島南東沖

Distribution of Depth in  根室半島南東沖 (Southeast offshore the Nemuro Peninsula)  

 

Area map of 根室半島南東沖

Area map of 根室半島南東沖 (Southeast offshore the Nemuro Peninsula) is defined for epicenter's analysis as below,  

 

Counts of occurrence per depth in 北海道東方沖

Counts of occurrence per depth  in 北海道東方沖(East offshore Hokkaido region)  is shown as below graph,  

Many great earthquakes have been occurred in this area. More than M7 are 6 times between 1919-2024 as showed in the graph below. 50km/40km/30km are major instead of 20km/10km. 50km/40km's curves are over even 1km's one now.It seems M8 or so on could be occurred in the case of the domino effect including not only 50km/40km, but also 10km/1km/etc.

50km(light blue)…This count is the 1st. The longest silent term was between 1939-1954 from M6.6 in 1939. After it, there was both rapid increase of 50km and following 40km. Moreover, M8.1 of 10km followed them. There were some rapid increases after great earthquakes, like as M7.5(1km) in 1924, M7.8(40km) in 1969, M7.1(50km) in 1973, and M8.2(30km) in 1994. In result, the count becomes the 1st. The the largest magnitude in this depth is M7.1 in 1973. 

40km(green)…The count is the 2nd. The curves of 40km/50km have been overlapped each other since 1964. The the largest magnitude in this depth is M7.8 in 1969. 

1km(red)…The count is the 3rd. After M8.2 of 30km in 1994, 52km/40km counts had grown rapidly. But, the curve is following them still. The the largest magnitude is M7.5 in 1924. 

30km(yellow green)…The count is the 4rd. The curve almost caught up 1km after M8.2 in 1994. But it couldn't even though M8.2 of 30km is the greatest one of all depth. It seems most of M8.2 energy has been absorbed by the bot aftershocks of 50km/40km. The last occurrence was in 2019. s M6.6 in 1945.

60km(blue)…The count is the 5th. The curve is following 50km/40km with similar pattern, but far less. The the largest magnitude in this depth is M7.0 in 2000.

20km(orange)… The count is the 6th. After M7.8 of 40km in 1969, the curve almost overlapped with 50km. But, around 1990, the silent terms became longer than 50km. The the largest magnitude in this depth is M6.2 in 1969 as one of the aftershocks of M7.8 of 40km on the same day. 

10km(yellow)… The count is the 7th. On M8.1 in 1958, the count was the 2nd behind 1km. But, at this time, 40km curve had almost caught up 10km. Because of slow growing of the counts, the curve is under 20km even though M8.1 of 10km in 1958 is the 2nd greatest one of all depths.  

others…omitted