Statistical evidence indicates that some triggering or promotion forward in time can occur in regions which are under high stress due to additional stress events of  small size. Among these are surface and body waves passing through a region.  Triggering may be dynamic with the promoted earthquake occurring at the same time as the stress event or delayed with an earthquake occurring later in time but still related to the stress event through water lubrication or other various geophysical effects on the faults. We have argued in this report for the past 35 years that this effect is most observable where the seismic waves are largest.  In general this occurs at distances from the rupture ends of  the earthquake producing those waves (mainshock) which we have termed nodal distances. These are defined by the formula D=360*m/n where D is the distance in degrees and m<=m where n an m are small integers. These are also the locations of  the maximum corrections to magnitude in the standard Jeffreys-Bullen tables. In addition there is focusing of  seismic energy from reflections and refractions of f the core-mantle and the inner-outer core boundary of  the earth. This focuses energy at the surface in the distance between 101 and 108 degrees (core-mantle) and 141-148 degrees (inner-outer core boundary). In this report we monitor seismicity at these distances following major earthquakes as experience has shown that strong and/or unusual earthquake are much more likely to occur at these distance from the mainshock. 



Antipodal (~180 degrees)


Southern Peru to

Argentina to

Loyalty Islands to

Honshu Japan to

Fiji to

Flores Sea to Barbados, Greenland,

Northern Peru to Sumatra, 


Outer shadow zone edge (141-148 degrees)


Southern Peru to

Argentina to Timor, Indonesia, 

Loyalty Islands to Poland, Ukarine, Cyprus, Bulgaria, North Macedonia, Bosnia and Herzgovina, Eastern Mediterranean, Crete, Black Sea, Northern, Central Mid-Atlantic, Poland, Bulgaria, Turkey, 

Honshu Japan to Ascension Island, Peru, Tarapaca, Chile, 

Fiji to   Norwegian Sea, Northern Mid-Atlantic,

Fox Islands to Southern Atlantic Ocean, Zimbabwe, South Indian Ocean, 

Flores Sea to Gulf of Mexico, Chiapas, Mexico, Massachusetts, Argentina, Guatemala, Virginia, Central Mid-Atlantic, South Carolina, Georgia, Maine, Argentina, Galapagos Is, Atacama Chile, Northern Mid-Atlantic, Massachusetts, South Carolina, Kentucky, Alabama, Central Chile, Guatemala, Chiapas, Mexico, 

Northern Peru to Qinghai, China, Ryukyu Islands,  Honshu, Japan, New Guinea, India, Ryukyu Islands, Shikoku, Japan, Papua, Irian Jaya, Carlsberg Ridge, Korea, Bali, Ryukyu Islands, Xinjiang, China, Papua New Guinea, Gujarat, India, 


Node 3 (120 degrees)


Southern Peru to

Argentina to

Loyalty Islands to Virginia, Haiti, New York State,

Honshu Japan to Panama, North Atlantic, Puerto Rico,

Fiji to Virgin Islands, Chile, Afghanistan, Quebec,   

Flores Sea to West Chile Rise, Southeast Pacific, Montana, Utah, Gulf of California, Southern, Baja California, Montana,  

Northern Peru to Fiji, Iran, Mayotte, Solomon Islands, 


P- and S- shadow zone edge and node 7 (101-110 degrees)


Southern Peru to

Argentina to

Loyalty Islands to Southern Texas, Oaxaca, Bouvet Is, Carlsberg Ridge, Ecuador, Argentina, eastern Mexico, Kashmir, Nicaragua, Texas,  

Honshu Japan to North Atlantic Ocean, Oaxaca, Guerrero,  Mexico,

Sumatra to Hawaii,  South Sandwich Islands,

Fiji to Peru, Gulf of Mexico, Colombia, Missouri, Peru, Ecuador,  

Qinghai, China to offshore Baja California, North Atlantic Ridge, New Mexico, Ohio, Virginia, Oklahoma, Kermadec Islands, Auckland, South Island, New Zealand,  Ohio, Baja California, South Pacific Ocean,  South, North Island, New Zealand, Tennessee, Southeastern Alaska, Gulf of California,  Kermadec Islands, Southern California,  

Northern Peru to South Africa, Lesotho, Romania, Zaire, Crete, Fiji, Arctic Ocean, Rat Islands, Zimbabwe, Congo, Auckland, South Island, New Zealand, Western Turkey, Kermadec, Tonga/Fiji Islands, Northern Greece, South Africa, South Island, New Zealand, Andreanof, Rat Islands, Near Islands, Crete, Cook Strait, New Zealand, Fiji Islands, Prince Edward Islands, Greece, Macquarie Islands, New Zealand, Rat Islands, South Africa, Greece, Romania, Dodecanese Islands, South Island, New Zealand, 


Node 4 (90 degrees)


Southern Peru to

Argentina to

Loyalty Islands to Southern Alaska, southern, central  California, Gulf of California, 

Honshu Japan to

Sumatra to

Fiji to Utah, Texas, Oaxaca, Mexico, Southern Idaho, 

Flores Sea to Alaska Peninsula,

Northern Peru to northern Italy, 


Node 5 (72 degrees)


Southern Peru to

Argentina to

Loyalty Islands to Sumatra, Kuril Islands, 

Honshu Japan to Tonga, Fiji, Central California, Idaho, Tonga, Southern Iran,

Sumatra to Loyalty Islands,

Fiji to Ryukyu Islands, Java, Honshu, Hokkaido, Japan, Northern Philippines,

Timor  Sea to Komandorsky Islands, Near Islands,


Node 6 (60 degrees)


Southern Peru to

Argentina to

Loyalty Islands to Bonin Islands, 

Honshu Japan to Vancouver, 

Sumatra to

Fiji to Mindanao, Philippines, Ceram, Indonesia, Sumbawa, 

Flores Sea to Tonga, Fiji,  Kashmir,

Northern Peru to western Montana, San Francisco, Geysers, California,  


Node 7 (52 degrees)


Southern Peru to

Argentina to

Loyalty Islands to Sulawesi, Indonesia,

Honshu Japan to Nicobar Islands, Kashmir, Tajikistan, 

Sumatra to Southern Iran, Antarctic Ridge, 

Fiji to Banda Sea, Indonesia,

Flores Sea to Fiji, Timor, South, North Island, New Zealand,  India, Nepal, Vanuatu,

Northern Peru to Northern Mid-Atlantic, Quebec, northern Gulf of California,