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)


Guatemala to

Near Islands to

Sulawesi to

Vanuatu to

Mindanao to

Central Chile to Southeastern China, 

Botswana to Hawaii


Node 7 (154-155 degrees)


Guatemala to

Near Islands to

Sulawesi to

Vanuatu to

Mindanao to

Central Chile to Central Honshu, Japan,

Botswana to


Outer shadow zone edge (141-148 degrees)


Guatemala to East Timor, India, Celebes,

Near Islands to

Sulawesi to Chiapas, Mexico, Central Chile, 

Vanuatu to

Mindanao to Central Chile, Nicaragua, Ascension Island,

Central Chile to Tajikistan, Sumatra, Guam, Sumba, Mindanao, Philippines, Molucca, 

Botswana to Southeastern Alaska, Kodiak Island, San Francisco, Mammoth Lakes, California, Coast of Oregon, Andreanof, Rat Islands, British Columbia, Southern Alaska, Andreanof Is, Seattle, WA, Nevada, Central California, Southern California,  Baja California, 


Node 3 (120 degrees)


Guatemala to Guam, Iran, New Guinea, Bismarck Sea,

Near Islands to Southern East Pacific, 

Sulawesi to Drake Passage, Baja California, Yellowstone, 

Vanuatu to Mozambique, Caucasus, Cuba, 

Mindanao to Texas, Culf of California, South Sandwich Islands, Oklahoma, North Atlantic Ocean, Western Texas,  

Central Chile to Fox Islands, Romania, 

Botswana to Guatemala, Eastern Mexico, Yap, Chiapas, Mexico, New Britain, Guam, Bonin Is. Japan, 


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


Guatemala to New Zealand, Honshu, Japan, Vanuatu, Western Turkey, Loyalty Islands, Crete, Southern Kurils,  

Near Islands to Ecuador, Peru,  

Sulawesi to Washington State, Southern East Pacific, Vancouver, B.C. Poland, Switzerland, England,

Vanuatu to Hindu Kush, Kansas, Chiapas, Mexico, Tajikistan, Central Chile, Veracruz, Mexico, Severnaya Zenlya, El Salvador, South Sandwich Islands, Xinjiang, China, Ecuador, Central Chile, Guatemala, Oklahoma, Tajikistan, Chiapas, Mexico, Hindu Kush, 

Mindanao to Yellowstone, Santa Barbara, California, Seattle, Washington, Northern, Central California, North Atlantic, 

Central Chile to Southeastern Alaska, Vanuatu, Italy, France, Iceland, Fiji, 

Botswana to Svalbard, Banda, Taiwan, Colombia, Mindanao, Celebes, Cuba, Dominican Republic, West Chile Rise, New South Wales, Australia, Banda, Ceram, South of Panama, Mindanao, Sulawesi, Ecuador, Mindoro, Philippines, Peru, South Island, New Zealand, Dominican Republic, Celebes, Banda Sea, 


Node 4 (90 degrees)


Guatemala to Fiji, Italy, Tonga, South Sandwich Islands, Kamchatka, 

Near Islands to Dominican Republic, Puerto Rico, Haiti,

Sulawesi to Kenai, Alaska, Turkey,

Vanuatu to Gulf of California, Idaho, western Jalisco, Colima, Mexico, Yukon, Canada, Washington, Nevada,

Mindanao to Southeastern Alaska, 

Central Chile to Tonga, Fiji, 

Botswana to Balleny Islands, Antigua, Iceland, Trinidad and Tobago, Central, Southern Peru,  Venezuela, Kazakhstan,


Node 5 (72 degrees)


Guatemala to Iceland, Andreanof Islands, Pribilof Is, Madeira Islands, 

Near Islands to Georgia, Caucasus, Banda Sea, Vanuatu, Ohio, Iraq, Guerrero, Mexico,

Sulawesi to Near Islands,  Andreanof Islands,

Vanuatu to Fox Islands, Kamchatka, Unimak Island, Alaska,

Mindanao to Fox Islands,  Andreanof Is,

Central Chile to Colima, New Madrid, Missouri, Tonga/Fiji, Texas, Oklahoma,  Gulf of California,

Botswana to Hindu Kush, Spain, Central Atlantic, France,    


Node 6 (60 degrees)


Guatemala to Los Lagos, Chile, Alaska, Hawaii

Near Islands to New Guinea, Oklahoma,

Sulawesi to Tajikistan, Macquarie Is, 

Vanuatu to Taiwan, Kyushu, Hokkaido, 

Mindanao to Tajikistan, Central Asia, Near Islands, 

Central Chile to Jalisco, Mexico,

Botswana to South Atlantic, Greece, Turkey


Node 7 (52 degrees)


Guatemala to SE Alaska,

Near Islands to Southern California,

Sulawesi to Sakhalin, Russia, Haryana, India, 

Vanuatu to Hawaii, Mindoro, Philippines,

Mindanao to Southern, Northern India, Kamchatka, Vanuatu, Loyalty Islands, 

Central Chile to  Northeastern Pacific Ocean, Eastern Mexico, France, Cuba, Dominican Republic, Guadeloupe,

Botswana to South Sandwich Islands,


Node 8 (45 degrees)


Guatemala to Vancouver Is, Northern, Central Chile,

Near Islands to Hawaii, Northern California, Taiwan,

Sulawesi to Sea of Japan,

Vanuatu to Mindanao, Philippines, Sulawesi, Indonesia, 

Mindanao to Vanuatu, 

Central Chile to Grenada, Southeastern Pacific, Nicaragua,  

Botswana to Carlsberg Ridge, Chagos,


Node 9 (40 degrees)


Guatemala to

Near Islands to

Sulawesi to Central Honshu, Japan,

Vanuatu to Ceram,

Mindanao to

Central Chile to

Botswana to Southern Mid-Atlantic, Yemen, Djibouti,