9/56 YEAR CYCLE:
EARTHQUAKES & VOLCANOES


MOON SUN FINANCE


David McMinn

Working Paper

Corrections & Research Suggestions Most Appreciated

Recently Published Papers

9/56 Year Cycle: Earthquakes in Peru, The Philippines and Selected US States
David McMINN
Being peer reviewed for publication in New Concepts in Global Tectonics Newsletter.

9/56 Year Cycle: Earthquakes in Selected Countries
David McMINN
New Concepts in Global Tectonics Newsletter
No 60. p 9-37. September 2011.
May be downloaded from ncgt.org

9/56 Year Cycle: Record Earthquakes
David McMINN
New Concepts in Global Tectonics Newsletter
No 59. p 88-104. June 2011.
May be downloaded from the ncgt.org web site

9/56 Year Cycle: Hurricanes
David McMINN
New Concepts in Global Tectonics Newsletter
No 59. p 105-111. June 2011.
May be downloaded from the ncgt.org web site

9/56 Year Cycle: Californian Earthquakes
David McMINN
New Concepts in Global Tectonics Newsletter
No 58. p 33-44. March 2011.
May be downloaded from the ncgt.org web site


A 9/56 year cycle was first established in patterns of US and Western European financial panics since the mid 18th century (Funk, 1932; 9/56 Year Cycle: Financial Crises). This cycle consists of a grid repeating the intervals of 56 years on the vertical (called sequences) and 9 years on the horizontal (called sub-cycles). Major financial crises tended to cluster with statistical significance in this grid pattern. A big question was whether other phenomena also occurred preferentially in this cycle or did it only apply to financial panics. The first link between the 9/56 year cycle and US earthquakes was made by McMinn (1994). This concept was expanded upon after assessing numerous historical listings of major earthquakes and volcanic eruptions. Many examples of a 9/56 year effect could be established for major earthquakes occurring around the world. This topic has been extensively covered on this web page.   

According to McMinn, the 9/56 year cycle was caused by Moon-Sun tidal effects. Any events clustering in a 9/56 year pattern will always have the lunar ascending node sited in two segments on the ecliptic approximately 180 degrees opposite WITH NO EXCEPTIONS. Events occurring around the same time of year will have apogee located in three ecliptical segments 120 degrees apart WITH NO EXCEPTIONS. The ascending node and apogee are key factors in cycles of terrestrial tides. How this tidal triggering actually functions remains completely unknown. Please refer to Appendix 1 for background information on this Moon-Sun effect. 

The 56 year sequences have been numbered in accordance with McMinn (1993), with 1817, 1873, 1929, 1985 being designated as Sequence 01, 1818, 1874, 1930, 1986 as Sequence 02 and so forth. McMinn (Appendix 2, 2002) presented the full numbering for those interested. The year of best fit has been applied in the various tables throughout the text. 


California Earthquakes


The US Geological Survey listed major quakes (mag => 6.9) occurring in California, Nevada and Baja California for the 1800-2000 period, with post 2000 events being inserted by the author (see Appendix 1). This compilation gave 31 events, of which 10 took place in the 12 months beginning April 15 of those years in Table 1. This compared with 2.5 that could have been expected by chance. Table 1 comprised five 56 year sequences or about 9% of the complete 9/56 year grid. However, it contained:        
*    36% of all major Californian earthquakes.                         
*    58% of all major Californian earthquakes taking place in October to December.

Table 1         9/56 YEAR CYCLE: MAJOR QUAKES IN
CALIFORNIA – NEVADA – BAJA CALIFORNIA 1800 – 2010 (mag => 6.9)
Year beginning April 15

Sq
25

 

Sq
34

 

Sq
43

 

Sq
52

 

Sq
05

 

 

 

 

1803

+ 9

1812
Dec08
Dec21

+ 9

1821

1841

+ 9

1850

+ 9

1859

+ 9

1868
Oct21

+ 9

1877

1897

+ 9

1906
Apr18

+ 9

1915
Oct03
Nov21

+ 9

1924

+ 9

1933

1953

+ 9

1962

+ 9

1971

+ 9

1980
Nov08

+ 9

1989
Oct18

2009
Aug03
2010
Apr04

 

 

 

 

 

 

 

 

Years in bold contained quakes (mag => 6.9) in the year beginning April 15.


Crucially, four 56 year sequences in Table 1 (Sqs 25, 34, 43 & 52) experienced many record events. 
*          Sqs 25 & 43 – First and second rank quakes in Baja California (mag 7.2. Apr 4,                                            2010 & mag 7.1 Nov 21, 1915).
*          Sq 34 – Record northern Californian quake (San Francisco. mag 8.25. April 18, 1906).
*          Sq 34 – Record New Mexico quakes happened on July 16 and November 15 in 1906 (both mag 5.8). 
*          Sq 34 - Equal first rank Arizona quake (Flagstaff. mag 6.2. Jan 25, 1906).  
*          Sq 43 - Record quake for Nevada (Pleasant Valley. mag 7.7. Oct 3, 1915).  
*          Sq 52 - Record quake for western USA (Great Cascadia. mag 9.0. Jan 26, 1700).
*          Sq 52 - Record quake for Hawaii (mag 7.9. Apr 2, 1868).          
*          Sq 52 - Record US volcanic eruption (ex Alaska) (Mt St Helens, May 18, 1980).

The notable exception was the record event for southern California (Fort Tejon, mag 8.25. Jan 9, 1857).

 

For the full text on Californian earthquakes.


Alaskan Earthquakes

Please see 9/56 Year Cycles: Alaskan Earthquakes


Alaskan Volcanic Eruptions

Based a paper by Motyka et al (1993), the ending of major Alaskan eruptions fell with statistical significance (p < .001) in patterns of the 36 ysc Series 1 & 2 (see Table A, Appendix 1). This may be spurious as numerous volcanoes ended their eruption in 1987 and the report was written in 1993. To counter possible distortions, all historic Alaskan eruptions were considered. Of the 220 listed by the National Geophysical Data Center (see Table B, Appendix 1), some 58 occurred in the 12 months ended December 31 of those years in the 36 ysc Series 1 & 2 (p < .001) (see Table 1). The notable eruption periods within the 36 ysc Series 1 & 2 were 1929-31, 1976-80, 1987 and 1996, which accounted for about two thirds of the volcanic eruptions that took place within Series 1 & 2.

Table 1
ALASKAN ERUPTIONS & THE 36 YSC S1/S2: 1790 - 1996
Year beginning January 1

36 Year Sub-Cycles Series 1

Sq 05

 

Sq 41

 

Sq 03

 

Sq 21

 

Sq 01

               

1817

   

1801

+ 18

1819

+ 18

1837

+ 36

1873

1821

+ 36

1857

+ 18

1875

+ 18

1893

+ 36

1929

1877

+ 36

1913

+ 18

1931

+ 18

1949

+ 36

1985

1933

+ 36

1969

+ 18

1987 

+ 18

 2005

 

 

1989

 

           

 

36 Year Sub-Cycles Series 2
Sq 52   Sq 32   Sq 50   Sq 12   Sq 48
                   1808
      1792 + 18 1810 + 18 1828 + 36 1964
1812 + 36 1848 + 18 1866 + 18 1884 + 36 1920
1868 + 36 1904 + 18 1922 + 18 1940 + 36 1976
1924 + 36 1960 + 18 1978 + 18 1996     
1980                 

Series 1 is displaced relative to Series 2 by an interval of 9 years. 
Adding 9 years to Series 2 gives Series 1.
Years containing Alaskan volcanic eruptions have been presented in BOLD.
Source of Raw Data: National Geophysical Data Center.

 

New York State Earthquakes

New York City. Won-Young Kim of Columbia University gave a listing of the significant quakes in the New York City region to 1999. Of the 18 events presented, 11 fell in the 12 months beginning June 1 of those years in Table B, Appendix 8 (significant p < .01). Remarkably, of the top 11 earthquakes (mag => 3.6), 7 occurred in these 9/56 patterns during the four months beginning August 1. The 8th rank quake also occurred in Table A, but on June 1, 1927.

New York State: 1735-1985. The University of Buffalo published a listing of 24 earthquakes in New York State between 1850 and 1985. Of this figure, 16 fell in the 12 months beginning April 20 of those years in the 9/56 year grid in Table B Appendix 8 (significant p < .01).

Western New York-Southern Ontario: 1850-1970. The University of Buffalo gave a listing of 19 earthquakes in western New York State and southern Ontario for the 1850-1970 era. Of this figure, 15 occurred in the year commencing April 20 of those years in Table D  Appendix 8, which compared with the expected frequency of about 5.1.

Other US Regions

Arizona Earthquakes,
Hawaii Volcanoes
,
Hawaii Earthquakes,
Maryland Earthquakes
Ohio Earthquakes
Oklahoma Earthquakes
,

Record US Quakes,

Chilean Earthquakes

Servicio Sismologico Universidad de Chile gave a comprehensive listing of Chilean earthquakes of mag =>7.0 since 1570. Of the total 95 earthquakes presented for the 1800 - 2009 era, 42 appeared in the 12 months beginning March 1 of those years in the 9/56 year grid shown in Table A Appendix 3 (significant p < .01).


Chinese Earthquakes

A listing of 34 major Chinese earthquakes (mag => 7.0) in the 1900 to mid 2008 era was compiled from data obtained from the National Geophysical Data Center. Of the total figure, 14 occurred in the 12 months beginning July 15 of those years in Table A Appendix 4 (marginally significant p < .05). Curiously, 7 earthquakes happened in the 1.5 months commencing July 15 of those years in Table A. This arises from seasonality - of the total 34 Chinese earthquakes, 12 occurred in the 50 days between July 10 and August 29, which was in contrast to an expected 4.6. 

Major Chinese earthquakes were least likely to happen in Sequences 22 to 36 of the 9/56 year cycle (see Table B Appendix 4), with only one event in 15 56 year sequences (significant p < .01).

 

Table A, Appendix 4          9/56 YEAR CYCLE: CHINESE QUAKES 1900 - 2004
Year beginning July 15

Sq
52
Sq
05
    Sq
32
Sq
41
Sq
50
Sq
03
Sq
12
Sq
21
    Sq
48
Sq
01
                    1902
0822*
1911 1920
1216
1929
        1904

1913

1922
1923
0324

1931
0810

1940

1949

1958 1967

1976
0727
0728

1985
0823
1924
1925
0316

1933
0825

1942 1951
1118
1960

1969
0718
1970
0104

1978

1987 

1996 2005        
1980

1989

1998  2007
2008
0320
0512
                   

The 56 year sequences in the table are separated from each other by an interval of 9 years. 
Years in bold contained major Chinese earthquakes in the 12 months commencing July 15.
Dates expressed as YYYYMMDD. 
Sources of Raw Data
: National Geophysical Data Center. Parameters:  China, 1700 to 2004. Mag 7.0 to 9.9
US Geological Survey. Earthquakes post  2004.


Indian Earthquakes.
 

Some 23 earthquakes were presented in the Earthquake History of India and How safe are we?, of which 10 took place preferentially in the 8 months ended August 30 of those years in the 9/56 year grid presented in Table A Appendix 5. The expected frequency was around 2.7. This grid was expanded to include 14 56 year sequences (see Table B Appendix 5), which contained 13 major earthquakes in the 12 months ended August 30 of those years in the table (significant p < .01).

Earthquakes in South East France - Appendix 6

New Zealand Earthquakes

The Institute of Geological & Nuclear Sciences presented a map of New Zealand major earthquakes (mag =>6.9) from 1840 to 2010, which were 'notable shallow earthquakes' (generally less than 30 kms depth). Of the 21 given, 12 showed up in the year beginning January 1 of those years in the 9/56 year cycle shown in Table A Appendix 7 (significant p < .01). More remarkably, 13 major New Zealand earthquakes happened in the 1840 - 1950 era, of which 10 events appeared in Table A, where as about 3.3 could have been expected chance.

Italian Earthquakes - Appendix 9.

Philippine Earthquakes - Appendix 10.

Peruvian Earthquakes - Appendix 11.

Iranian Earthquakes

The USGS listed 20 major earthquakes for Iran during the 20th century, of which 15 occurred in 12 months beginning September 1 of those years in the 9/56 year patterns (see Table A, Appendix 12) (significant at p < .001).

Canadian Earthquakes - Appendix 14.

Australian Earthquakes

The Seismology Research Centre presented a map of major earthquakes in Australia since about 1880, while the University of Western Australia gave a listing of major earthquakes in Western Australia since 1870. These sources were combined, giving a total of 26 earthquakes (mag => 6.0) for the period 1870-1998. Of the top 16 quakes (mag => 6.4), 9 occurred in the 12 months commencing July 1 of those years in Table A
Appendix 15,  which is in contrast to the expected frequency of about 3.1. Even more remarkably, 6 quake events in Sequences 41, 50, 03 and 12 (see Table A Appendix 15) happened in the 6 months ended June 30 of the following year, where as 0.9 could have been expected by chance. Significance was mainly associated with the most extreme events. For the 10 lesser quakes (magnitude between 6.0 and 6.3), only three fell in Table A, which could be expected by chance.

Mexican EarthquakesAppendix 16.

Icelandic Earthquakes

The Icelandic Meteorological Office published a listing of major Icelandic earthquakes between 1706 and 2000. There were 25 events with a magnitude =>6.0, none of which occurred in the four months beginning September 10. Of the total figure, 20 fell in the year beginning January 15 of those years in the 9/56 year grid in Table A, Appendix 17 (significant p < .001). In Table A, the events clustered into the 3.5 months beginning January 15 (9) and the month beginning August 10 (9), with anomalies on June 2, 1934, as well as January 13 , 1976 of the following year.

Eastern Mediterranean Earthquakes

According to the The Geophysical Institute of Israel data base, 26 major quakes (mag => 5.30) happened in the eastern Mediterranean region between 1900 and 2005. Of this total, 13 occurred in the year ending October 15 of those years in the 9/56 year cycle presented in Table A Appendix 18 (significant p < .01).

South African Earthquakes - Appendix 19.

Algerian Earthquakes - Appendix 20.

Greek Earthquakes

The National Geophysical Data Center produced a listing of major Greek earthquakes between 1860 and 2001. There were 40 events with a magnitude =>6.5, of which 16 fell in years ended December 31 in Table A Appendix 21 (significant p < .01).

Argentine Earthquakes

The Instituto Nacional De Prevencion Sismica listed some 57 Argentine (mag =>5.0) earthquakes that occurred between 1780 and 1995. Of this figure, 32 occurred in the 12 months beginning January 20 of those 9/56 years in Table B Appendix 22 (significant: p < 10-4).

Major World Earthquakes

Kazuya Fujita of the Michigan State University presented a listing of the 45 biggest earthquakes occurring around the world between 1900 to 2004. Of this total figure, 15 happened within the 8.5 months to August 22 of those years in Table B Appendix 23 (significant p < .01). 

The United States Geological Survey presented a listing of 45 biggest recorded earthquakes (mag =>8.0) occurring around the world between 1700 to 2006. Of this total figure, 15 happened in the 12 months ended June 15 of those years in the 9/56 patterns in Table A, Appendix 24 (significant p < .001). This effect best applied to the biggest recorded earthquakes. Of the 22 largest world quakes (mag =>8.3), 11 appeared in the 9/56 year grid in Table A, Appendix 24, whereas 3.1 could have been expected by chance.

Other Countries.

Listings for several other countries assessed could not be linked statistically (p > .01) to 9/56 year grid patterns. This applied to Japan, Taiwan, Turkey, United Kingdom and several others. Thus there is an anomaly, which is difficult to explain. Why should the 9/56 year seismic trends show up in most countries/regions, but various anomalies arise that do not support the 9/56 year cycle effect. Alas, this issue cannot be resolved based on current limited knowledge. It could be reasonably hypothesised that a 9/56 year seismic cycle shows up worldwide, but with variations according to the location on the Earth's surface. 

Tsunamis

Given that quakes fall preferentially in 9/56 year patterns, it may reasonably be postulated that the same geological forces give 9/56 year patterns in the timing of large tsunamis. There is some evidence to support such a proposition. 

Chile. Curso Geografia Del Mar listed major tsunamis that occurred on coastal Chile since the mid 16th century. The biggest tsunami events (categories 3 & 4) gave 14 events (see Table A, Appendix T1), of which 8 occurred in the 8.5 months ended those years in Table B, Appendix T1. In contrast, 2.1 could have been expected by chance. Strangely, Region del Biobio experienced no events within the 9/56 patterns. If the full 35 events are considered (all categories 1 to 4), significance is extinguished. This is a reasonably consistent feature - the 9/56 year effect seems most applicable to extreme events whether they are earthquakes, volcanic eruptions or tsunamis.  

Peru. The Tsunami Research Center (University of South Carolina) listed 13 major historic tsunamis along the Peruvian coast. Of this total, some 7 happened in the years in Table B Appendix T2, which compares with the expected frequency of 2.8. Dates were given where ever possible.

July 9, 1586
November 24, 1604
1647
October 20-21, 1687
October 28, 1746
1865
April 16, 1868
1914
1942
1960

1966
February 21, 1996
June 23, 2001

"Of those listed, five were particularly destructive. These include the 1586, 1604, 1687 and 1746 tsunamis, as well as the 1868 Arica tsunami". Of these, only the 1746 event did not fall in Table B, Appendix T2.

Hawaii. The map titled Hawaii Tsunamis listed some 26 historic tsunamis for the island of Hawaii in the period 1815 to 1975, of which 13 fell in the 9/56 year grid shown in Table B Appendix T3. This finding was highly significant (p < .001). Unfortunately, a source for this map could not be given despite a thorough internet search. If anyone is able to assist, please email the author.

Conclusions

The 9/56 year seismic cycle could be established for many countries and regions around the world. Thus the concept was firmly supported

 The Moon, The Sun  & The Number 56. Thus major earthquakes could be expected to occur preferentially in the 9/56 year cycle, because of Moon - Sun tidal triggering. Both Alaskan seismic and volcanic upheavals happened preferentially in 9/56 year patterns. A major problem is to explain why Alaskan eruptions fall within the 36 ysc Series 1 & 2, but not Alaskan earthquakes. There is an anomaly, which is difficult to clarify. 9/56 year cycles could also be found in seismic patterns in China, Chile, India, USA, New Zealand and various other countries. Some seismic listings were tested, but yielded no significance between the timing of earthquakes and 9/56 year patterns (p > .01).  This failure applied to Japan, UK, Greece, Turkey, Taiwan and various other countries for whatever reason. More research is warranted in this field to clarify such anomalies.

Earthquakes take place with statistical significance in 9/56 year patterns for most countries assessed. When listed chronologically, quakes would appear to be just a random collection of dates without any regular periodicity. Hence the 9/56 year seismic cycle cannot be considered a 'cycle' in the traditional sense of events happening every so many years, months, days and so forth. 

Currently, this cycle offers little in the way of forecasting earthquakes accurately, as it is only statistically valid. Thus, a 9/56 year seismic/eruption cycle, even if proven convincingly, would be more of scientific interest rather than a good predictive tool. At best it may offer insights into windows periods when earthquakes are most likely to happen. Even so this could potentially save many lives. Only time and much more research can tell if this was achivable..

Copyright © 2002-2007. David McMinn. All Rights Reserved.

Glossary

Apogee is the point in the Moon's orbit greatest distance to the Earth.
Annual One Day rise or fall is the biggest one day % rise or fall in the year commencing March 1.
Ecliptic.
The plane of the Earth's orbit around the Sun, which is inclined at 23.5 degrees to the plane of the Earth's equator.
Equinoxes
are node points where the plane of the Earth’s equator cuts the ecliptic. At these points, the equatorial ascending node is where the Sun passes from below to above the celestial equator at 0 E
o (0 Aries - vernal or spring equinox at around 20 March) as viewed from the northern hemisphere. The equatorial descending node is where the Sun passes from above to below the celestial equator at 180 Eo (0 Libra - autumnal equinox at around 22 September).
Month, Apogee
(or Anomalistic Month) is the time taken for the Moon to complete one cycle from apogee to apogee and equals 27.5546 days.
Month, Nodical
(or Draconic Month). The time taken for the Moon to complete one cycle north node to north node and is equal to 27.2122 days.
Month, Sidereal.
The time taken for the Moon to travel from a fixed star back to the same fixed star. It is almost exactly equivalent to the tropical month and equals 27.3217 days.
Month, Synodic (or Lunar Month). The time taken for the Moon to complete one cycle new Moon to new Moon and is equal to 29.5306 days.
Month, Tropical.
The time taken for the Moon to complete one 360 degree cycle of the ecliptical  circle and equals 27.3216 days.
Moon's Orbital Plane
is the plane of the Moon's orbit around the Earth, which is inclined by 5 degrees to the ecliptic plane.
Nutation Cycle.
The time taken for the Moon's north node to complete one 360
o cycle retrograde (ie: clockwise) through the ecliptic circle and equals 18.6133 tropical years.
Node.
In astronomy, these are two points (eg: equinoxes, lunar nodes, etc) where the orbit of a heavenly body cuts an astronomical plane or where two astronomical planes intersect.
Node, Moon’s
. The plane of the Moon's orbit is inclined at 5
o to the plane of the Earth's orbit around the Sun (the ecliptic). The lunar nodes are the points where these two planes intersect. The north or ascending node is where the Moon passes from below to above the ecliptic (South to North). The south or descending  node is where the Moon passes from above to below the ecliptic (North to South).
Saros Cycle.
This is the interval between two similar eclipses (every 223 lunar months or 6,585.32 days) when the relative angles between the Sun, Moon and Moon’s nodes repeat to within a degree.
Year, Nodical
(or Eclipse Year). The time taken for the Sun to complete one cycle north node to north node and equals 346.6201 days.
Year, Tropical.
(or Solar Year) Time taken for the Sun to complete one cycle of the ecliptic circle from spring equinox to spring equinox and is equal to 365.2422 days.

References

Funk, J M. The 56 Year in American Business Activity. Privately published. 1932.
McMinn, David. Mob Psychology & The 56 Year Cycle. The Australian Technical Analysts Association Newsletter. P 28-37. March 1994.
McMinn, David. Market Timing By The Number 56. Twin Palms Publishing. First Edition 2002. Revised 2004.
Stover, C W & Coffman, J L. Seismicity of the United States, 1568-1989 (Revised), U.S. Geological Survey Prof. Paper 1527, 1993.

Appendix 1

The 9/56 Year Moon - Sun Cycle 

Financial crises give far more regular cycles than seismic upheavals. Within the sequences, financial distress often repeats every 56 years and often about the same month within a particular sequence. Then there are the various sub-cycles in multiples of 9 years and associated artifact sub-cycles. Such regularity does not appear to be applicable to earthquakes or volcanic eruptions. This discrepancy may possibly be explained in terms of the different mechanisms involved. Financial crises are believed to arise by lunisolar cycles influencing mass human physiological cycles and thereby activating cyclic changes in the collective mood ranging between optimism and fear. Such a process would give fairly repetitive cycles, with financial crises occurring when there is a sudden shift in market sentiment from optimism to fear. However, geophysical upheavals require a build up of stresses either along active fault lines or under a volcanic vent, before they can be released suddenly in a major cataclysm. It may take decades or even centuries before stresses build up sufficiently before another earthquake/eruption can be activated in a particular region by Moon - Sun tidal resonance.

Nutation Cycle. The ecliptical position of the north (ascending) node on a particular date can be correlated perfectly with the 9/56 year grids. On July 1 for ALL years in the 36 year sub-cycles Series 1 (see Table 1), the north (ascending) node was always sited between 328 and 58 Eo, while, for ALL years in Series 2, the north node appeared between 142 and 231 Eo (see Diagram 1). For such patterns to occur by chance would be infinitely small. One would expect an even ecliptical distribution of the north node, if there was no relationship with 9/56 year patterns. Thus these 9/56 year patterns can be strongly related with the 18.6 year nutation cycle and, by implication, Moon - Sun tidal effects.

 

 DIAGRAM 1    NORTH NODE ECLIPTICAL POSITION & THE 36 YEAR SUB-CYCLES

As on July 1 - All 44 years in the 36 ysc Series 1 & 2 - 1760-2000
Source: The Moon, The Sun  & The Number 56

Moon - Sun cycles may also be linked to eclipse cycles. Based on integral and half integral numbers, several Moon - Sun cycles align very closely at 9.0 and 56.0 tropical years. 

HALF SAROS CYCLE

Days Years Lunisolar Cycles
3,287.18  9.000 9.0 Tropical Years
3,292.89   9.016  9.5 Nodical years
3,292.66   9.015  111.5 Synodic Months
3,292.26   9.014 120.5 Tropical Months
3,292.68   9.015  121.0 Nodical Months
56 YEAR CYCLE
Days Years Lunisolar Cycles
20,453.55  56.000  56.0 Tropical Years
20,450.58  55.992  59.0 Nodical Years
20,449.94  55.990  692.5 Synodic Months
20,450.23  55.991  748.5 Tropical Months
20,449.97  55.990  751.5 Nodical Months


18 Year Saros Cycle. Every 223 synodic months (one Saros cycle), the Sun, Moon and the Moon's nodes align in the same relative angles to each other to within a fraction of a degree. The Saros (18.0 tropical years) divided by two gives the Half Saros Cycle. Every 9.0 tropical years or 111.5 synodic months, the Moon's mean relative position is the same angle to the lunar north node, with the Sun 180o on the opposite side of the ecliptic circle.

56 Year Cycle. On the same date every 56, the ecliptical position of the lunar north node moves only 3 Eo clockwise (eg as on July 1: 1761 - NN at 48 Eo; 1817 - 45 Eo; 1873 - 42 Eo; 1929 - 39 Eo; 1985 - 36 Eo). This is a very close alignment of two cycles - the tropical year and lunar nutation. Furthermore, every 56.0 tropical years or 692.5 synodic months, the Sun's relative position forms the same angle to the north lunar with the Moon 180o on the opposite side of the ecliptic circle. The two cycles of 9.0 (half Saros) and 56.0 tropical years result in alternating full/new moons every 111.5 and 692.5 synodic months respectively.

Every 9.0 and 56.0 years the relative angles between the Moon, Sun and lunar north node repeat the angles 0 or 180 degrees to within one degree.

The Saros and Half Saros cycles show up in Moon Sun eclipse cycles as listed by Robert van Gent. He also gave a 112 year cycle, which divided by two yields the 56 year eclipse cycle.

Apogee is the point (given in ecliptical degrees) in the lunar orbit, where the Moon is the greatest distance from Earth, while perigee is the least distance. In the lunar apse cycle, the apogee – perigee axis (apsides) rotates counter clockwise around the ecliptical circle from spring equinox to spring equinox every 8.8474 tropical years. The apsides axis is very important in oceanic tides on Earth. When the full/new Moon is at apogee, the amplitude of tides in New York Harbor is 50% lower than when the full/new Moon is at perigee. Apogee could be expected to play a key role in any Moon Sun seismic effect.

Apogee takes 5.995 tropical years to complete one cycle ascending node to ascending node. The 18.0 year Saros eclipse cycle divided by 6 produced the integral number three and the 9 year Half Saros divided by 6 gave 1.5 (one plus a half). The 56 year cycle divided by 6 gave 9.3333 tropical years (9 plus one third). Additionally, 9.0 divided by the 8.8474 year apse cycle yielded 1.02, while 56.0 divided by the apse cycle gave 6.33 (6 plus one third). For apogee, there was an emphasis on the 1st, 2nd and 3rd harmonics in the 9/56 year grid and this may also show up in tidal cycles. In the 9/56 year grid, apogee will be located in three segments approximately 120o apart on the ecliptical circle with no exceptions.