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)


Guerrero, Mexico to

Vanuatu to

Haiti to

South Sandwich Islands to

Mindanao, Philippines to

Alaska Peninsula to South of Africa

Qinghai China to West Chile Rise, 

Kermadec Islands to Algeria, northwest Africa, Southern Spain, 


Outer shadow zone edge (141-148 degrees)


Guerrero, Mexico to Andaman Is, Owen Fracture Zone, Java, Sumbawa, 

Vanuatu to  Sicily, Italy, England,

Haiti to Andaman Is, Papua, New Guinea, Mindanao, 

South Sandwich Islands to Arctic Ocean, Mariana Islands, Southeast Alaska, Mongolia, Siberia, 

Mindanao, Philippines to Central Mid-Atlantic, North Atlantic Ocean, Haiti, Nicaragua, Dominican Republic,

Alaska Peninsula to Scotia Sea, South Atlantic,  

Qinghai China to East Pacific Rise, Peru, Ecuador, 

Kermadec Islands to Caucasus, Central Mid-Atlantic, North Atlantic Ocean, Congo, Iraq, Ascension Is, Reykjanes Ridge, Iceland, 


Node 3 (120 degrees)


Guerrero, Mexico to Iraq,

Vanuatu to

Haiti to Vanuatu, Central Honshu, Japan, North Island, New Zealand,  

South Sandwich Islands to Afghanistan, Greenland Sea, Halmahera, Utah, Wyoming, New Guinea, Southern, Central California, Mindanao, Philippines, 

Mindanao, Philippines to South Sandwich Islands,

Alaska Peninsula to Los Lagos, Chile, 

Qinghai China to Jalisco, Mexico, 

Kermadec Islands to  Quebec, Virign Islands, La Soufriere, Barbados, Tajikistan, Baffin Bay, Quebec,  Hindu Kush,  

North Island, New Zealand to  La Soufriere, Namibia, Barbados, Xinjiang, China, Tajikistan,  Puerto Rico,

Honshu Japan to Guadeloupe, Panama,


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


Guerrero, Mexico to South Island, New Zealand, Romania,  Izu, Bonin Islands, Honshu, Japan, South Sandwich Islands, 

Vanuatu to Guerrero, Mexico, Tajikistan, Scotia Sea, Veracruz, Mexico, South of Africa, Afghanistan, Oklahoma, Hindu Kush, Guatemala, South Sandwich Islands, Gujarat, India, 

Haiti to Kuril Islands, South of Africa, Siberia, Sea of Okhotsk,

South Sandwich Islands to Fiji, northern Mexico, Northern Mid-Atlantic, Texas, Greece, Tennessee, Georgia, Michoacan, Mexico, Loyalty Islands, Dodecanese Islands, Vanuatu, North Carolina, Tonga/Fiji, Sicily, Italy, Croatia, Mt. Merapi, Sumatra, Vanuatu, southern Greece, northern Spain, northern Mexico, 

Mindanao, Philippines to Nevada, New Jersey, Sumatra, Iceland, Idaho, Southern, Central California, Baffin Bay, Canada, 

Alaska Peninsula to West Chile Rise, North of Australia, Gulf of Aden, Java, South Indian Ocean, South Island, New Zealand, Southeast Pacific, Sumatra, Nicobar Islands, Southern Peru, South Island, New Zealand, 

Qinghai China to Ohio, Maryland, South Island, New Zealand, Kermadec Islands, Indiana, Ontario, Quebec, Canada, Lake Erie, Utah, Southern California, South Dakota, North, South Island, New Zealand, Western Oklahoma, Baja, Mammoth Lakes, Santa Barbara, California, South Island, New Zealand, Kermadec Islands, Southern California,

Kermadec Islands to Cuba, Northwest Territories, Canada, Southern Mid-Atlantic, South Dakota, Texas, Wyoming, Caribbean Sea, Kansas,  Northern India, Louisiana, Indian Ridge, Beaufort Sea, Mongolia, Carlsberg Ridge, Siberia, Kansas, Oklahoma, Northern Alaska,  Myanmar,


Node 4 (90 degrees)


Guerrero, Mexico to

Vanuatu to Gulf of California,

Haiti to

South Sandwich Islands to

Mindanao, Philippines to

Alaska Peninsula to Banda Sea, Nicobar Islands, Iran, Dodecanese Islands, Greece, Northern Peru, Gibraltar, Algeria,, Kermadec Islands, East Pacific Rise, 

Qinghai China to

Kermadec Islands to South Sandwich Islands, New Mexico, Mt. Hood, Oregon, Alaska, Oaxaca, Guerrero Mexico, Utah, Washington, Chile,


Node 5 (72 degrees)


Guerrero, Mexico to

Vanuatu to South East Pacific Rise, Unimak, Fox Islands, South of Alaska, 

Haiti to Alaska Peninsula,

South Sandwich Islands to 

Mindanao, Philippines to

Alaska Peninsula to Haiti, Admiralty Islands, 

Qinghai China to Central Alaska, Congo, Baffin Bay, Canada, 

Kermadec Islands to West Chile Rise,


Node 6 (60 degrees)


Guerrero, Mexico to West Chile Rise, Unimak Islands, Central Chile, 

Vanuatu to Hokkaido, Taiwan, 

Haiti to Mid-Atlantic, South East Pacific Rise, West Chile Rise, 

South Sandwich Islands to

Mindanao, Philippines to Fiji,

Alaska Peninsula to Guam, Guerrero, Veracruz, Oaxaca, Mexico,

Qinghai China to Andreanof Islands,

Kermadec Islands to Molucca Sea, Ceram, Indonesia, Mariana Islands, 


Node 7 (52 degrees)


Guerrero, Mexico to Southeastern Alaska, northern Chile, Hawaii,  

Vanuatu to Hawaii,

Haiti to Canary Islands, Mid-Atlantic, Coast of Northern California, Coast of Oregon, Central Chile, 

South Sandwich Islands to South Africa, Southern Peru, northern Chile, 

Mindanao, Philippines to

Alaska Peninsula to northern Mexico, Volcano Is, Quebec, Ohio, Newfoundland, Western Mexico,

Qinghai China to

Kermadec Islands to New Guinea, South of New Guinea,  Hawaii


Node 8 (45 degrees)


Vanuatu to

Haiti to Central California,

Mindanao, Philippines to

Alaska Peninsula to Honshu, Japan, Oklahoma, Texas, Gulf of California,  Sonora, Mexico, Siberia,