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)


Michoacan, Mexico to

Taiwan to

New Guinea to

Central Mid-Atlantic to New Britain,

Sichuan, China to Central Chile, Central East Pacific, 

Luzon, Philippines to

Southern Peru to Vietnam, 

Loyalty Islands to

Sumatra to Colombia,


Outer shadow zone edge (141-148 degrees)


Michoacan, Mexico to Sumatra, 

Taiwan to Panama, Colombia, Southern Atlantic, South Sandwich Islands,

New Guinea to Dominican Republic, Mid-Atlantic, Azores, northern Atlantic, 

Central Mid-Atlantic to Izu Islands, Japan, Kermadec Islands, Mindanao, 

Sichuan, China to Colombia, East Pacific Rise,

Luzon, Philippines to Central Mid-Atlantic, Dominican Republic, Puerto Rico, West Chile Rise, Southern Chile, Central Mid-Atlantic, Puerto Rico, Nicaragua, Dominican Republic, 

Southern Peru to Papua, Guam, Izu,  Bonin Islands, Honshu, Japan, Mariana Is, Papua New Guinea, 

Loyalty Islands to Reykjanes Ridge, Dodecanese Islands, Greece, Turkey, 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, 


Node 3 (120 degrees)


Michoacan, Mexico to

Taiwan to Western Mexico, 

Luzon, Philippines to Michoacan, Mexico, New York City, 

New Guinea to Chiapas, Mexico, Iceland, Los Lagos, Chile,  

Central Mid-Atlantic to Sumatra, Sichuan, China,

Sichuan, China to Central Mid-Atlantic, 

Southern Peru to Kuwait, Santa Cruz Is,

Loyalty Islands to Virginia, Haiti, New York State, Southern Iran,  

Honshu Japan to Panama, North Atlantic, Puerto Rico,


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


Michoacan, Mexico to Mariana Islands, Bonin Islands, Kyushu, Crete, South Sandwich Islands, 

Taiwan to Reykjanes Ridge, Southern California,  Yellowstone National Park, Northern Mid-Atlantic, 

New Guinea to Turkey, Baja California, Yellowstone, Wyoming, 

Central Mid-Atlantic to Botswana, Central Alaska, 

Sichuan, China to northern, Central California, Quebec,  

Luzon, Philippines to Reykjanes Ridge, Yellowstone, Wyoming, Quebec, Idaho, Wyoming, Colorado, Pacific-Antarctic Ridge, South Africa, Central California, 

Southern Peru to Dodecanese Islands, Greece, Tanzania, Turkey, Svalbard, Pribilof Is, South Island, New Zealand, Alaska Peninsula, Fiji, South of Alaska, Unimak Island, Alaska, 

Loyalty Islands to El Salvador, Xinjiang, China, Nicaragua, Guatemala, Oklahoma, Western Texas, Mongolia, Southern Texas, Oaxaca, Bouvet Is, Carlsberg Ridge, Ecuador, Argentina, eastern Mexico, Kashmir, Nicaragua, Texas,  

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


Node 4 (90 degrees)


Michoacan, Mexico to

Taiwan to Coast of Northern California, Washington,

New Guinea to

Central Mid-Atlantic to Yellowstone, WY, Gulf of California, Afghanistan, 

Sichuan, China to Hawaii, Fiji, 

Luzon, Philippines to Iceland, France-Germany,

Southern Peru to England,  Hawaii, Iceland, 

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

Honshu Japan to


Node 5 (72 degrees)


Michoacan, Mexico to

Taiwan to Southern, Central Alaska, Fiji, Tonga,

New Guinea to

Central Mid-Atlantic to

Sichuan, China to Tanzania,  Santa Cruz Is,

Luzon, Philippines to Fiji, 

Southern Peru to Northern California, 

Loyalty Islands to Sumatra, Kuril Islands, 

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


Node 6 (60 degrees)


Michoacan, Mexico to Reykjanes Ridge, 

Taiwan to Andreanof Islands, Alaska, Santa Cruz Islands, 

New Guinea to

Central Mid-Atlantic to

Sichuan, China to New Britain, 

Luzon, Philippines to Southern Iran, 

Southern Peru to Maine, 

Loyalty Islands to Bonin Islands, 

Honshu Japan to Vancouver, 


Node 7 (52 degrees)


Michoacan, Mexico to

Taiwan to Pakistan, Santa Cruz Is,

New Guinea to Sumatra, 

Central Mid-Atlantic to Northern Chile,  Colombia, Dominican Republic,

Sichuan, China to

Luzon, Philippines to Santa Cruz, Is,

Southern Peru to

Loyalty Islands to Hawaii, Sulawesi, Indonesia,

Honshu Japan to Nicobar Islands, Kashmir, Tajikistan,