Counts of occurrence per depth in 長野県北部

Counts of occurrence per depth in 長野県北部（Northern Nagano Pref.）is shown as below graph,

Most occurrences are occupied with the ones of "unknown details (inknown)" of   "Matsushiro Earthquake Swarm" since 1965. It was occurred around 1km-20km in the narrow area. Even the huge occurrence, only M5.9 is the largest one of 1km before and after  it. The long silent terms of 20km/30km seems to be the sign of it. The start counts of the rapid increases were often near to the count of shallower depth's ones.  

• 1km (red)…The count is the 1st. There was the rapid increase as "Matsushiro Earthquake Swarm" since 1965. Most of them were "unknown" ones with no magnitude data occurred narrow area around "Matsushiro". The epicenters of "unknown" was almost constant until 1950. The constant "unknowns" moved to south  a little, and went into the swarm.  So, the rapid increase of 1km in 1941 seems to be the sign of "Matsushiro Earthquake Swarm" since 1965. The largest one of 1km is M5.9 in 1943. Though M5.9 were also occurred in 1986/in 2011, no more magnitude has been recorded. 
• 10km(yellow)⋯ The count is the 2nd. 10km curve was following behind 1km curve. There was the longest silent term between 1926 - 1935. Right after it, 10km curve increased with steep slope. Then, there was the silmllar increase by M6.1 of 10km in 1941. Then, the silent terms became longer gruadually just before the rapid increase  by "Matsushiro Earthquake Swarm" since 1965. After the rapid increase in 1965, the slope became gentle. There was also the rapid increase of 10km by M9.0 Great East Japan Earthquake in 2011 though the curve change looks like small because of logarithmic axis. M6.7 was induced by the M9.0 in 2011. The M6.7 is the greatest one of all deprhs in this area. Another M6.7 was also occurred in 2014. Before the later M6.7, there was a long silent term of 20km between 2011-2014. It seems to be the sigh of it. 
• 20km(orange)⋯The count is the 3rd. There was the longest silent term of 20km at that time between 1919-1935 as the 3rd one. Then, the silent terms became shorter. Furthermore they were accelerated by the M6.1 of 10km in 1941, and M5.7 of 20 km was occurred in 1947 at the count 12. The count is very near to the count of 10km as the start point of the acceleration when M6.1 was occurred at count 11 n 1941. Right after the M6.7 of 20km, the longest silent term was updated as between 1947-1954 as the 2nd one. The 2nd longest silent term may be the sign of  "Matsushiro Earthquake Swarm" started 1.5 month later in 1965. After the rapid increase of 20km since 1965, the 1st longest silent term of 20km was occurred between 1976-1995 at the count between 55-56. At the count 56 of 1km, the rapid increase of 1km was started in 1935. The latest occurrence of 20km is at count 86 in 2018. At count 87 of 1km, the rapid increase of 1km started in 1941. The largest one of 20km is the M5.7 in 1947. 
• 30km(yellow green)⋯The count is the 4th. There was the longest silent term at that time between 1941-1966 as the snd one at the count between 3-4. At the count of 1km between 2-3, the 3rd longest silent term of 20km was occurred between 1919-1935. The 2nd longest silent term of 20km between 1947-1965 was covered with the 2nd longest one of 30km between 1941-1966. The latest occurrence was in 1968. Sine 1968, the 1st longest silent term of 30km has been extended. The largest one of 30km is M4.5 in 1936. 
• others⋯omitted.

Counts of occurrence per depth in 長野県北部（Northern Nagano Pref.）since 1970 is shown as below graph (Each count is reset as started since 1970) , 

MD-T chart in 長野県北部

MD-T chart in 長野県北部（Northern Nagano Pref.）

note : Most of the data of "Matsushiro Earthquake Swarm" since 1965 are "unknown" data with no magnitude data. So, most of them are no plot.  Even so, there were very few data including "unknowns" before the swarm as only 1-4 times per a year between 1959- 1964 in fact.  

MD chart in 長野県北部

MD chart in 長野県北部（Northern Nagano Pref.）

note : Most of the data of "Matsushiro Earthquake Swarm" are "unknown" data with no magnitude data. So, most of them are no plot. Even so, many plots of them are still there as small balls.  

Dragon chart in 長野県北部

Dragon chart in 長野県北部（Northern Nagano Pref.）is as below,

The quantities per depth are 1km>>10km>>20km>>30km>>40km. The plots among 20km/30km/40km are located almost on a line with a slope of 1 (see "Analysis for the chart of maximun Magnitude per the depth of epicenter (Dragon Chart)").

Sum of Magnitude per 1day in 長野県北部

Sum of Magnitude per 1day in 長野県北部（Northern Nagano Pref.）

note : Horizontal axis isn't linear. Most of date are skipped as the horizontal label. All "unknown" data are plotted with no peak because of no magnitude data. So, most of the data of "Matsushiro Earthquake Swarm" since 1965 have no peak. 

Distribution of Magnitude in 長野県北部

Distribution of Magnitude in 長野県北部（Northern Nagano Pref.）is as below,

As the most of  "Matsushiro Earthquake Swarm" since 1965 are recorded as "unknown" with no magnitude data, they are not included in the below graph. The peak around ln M=0.6 (M=2.6) is consisted mainly by the data after 2011 induced by M9.0 Great East Japan Earthquake.

  

Distribution of Depth in 長野県北部

Distribution of Depth in 長野県北部（Northern Nagano Pref.）

Most of  "Matsushiro Earthquake Swarm" since 1965 are recorded as "unknown" with no magnitude data. They are counted as 1km in my blog as same as other area. So, the 1km's count almost become 10,000 times far more than 10km's one. In most areas with enough data, the both count of 1km/10km tend to become almost same counts. Or, 1km's count tend to become more a lille bit than 10km's ones. This case is abnormal one.