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)


Peru to Nias, Sumatra, Indonesia, 

Ecuador to Nias, Sumatra, Indonesia, 

Mindanao, Philippines to

Sulawesi to

New Guinea to

New Britain to Central Mid-Atlantic,


Outer shadow zone edge (141-148 degrees)


New Britain to Dominican Republic, Haiti, Puerto Rico, 

New Guinea to Puerto Rico, Virgin Islands, 

Peru to Uzbekistan, Northern Territory, Australia, Ryukyu Islands, Papua New Guinea, Honshu, Japan, Pakistan,  

Ecuador to Northern Territory, Australia, Mid-Indian Ridge, Kyushu, Japan, Gujarat, India, Ryukyu Islands, New Guinea,  Western Australia,

Loyalty Islands to South Atlantic, Crete,

Minahasa to Buenos Aires, Argentina, Baja California, Central Chile, Oaxaca, Mexico, 

Sulawesi to El Salvador, Argentina, 


Node 3 (120 degrees)


New Britain to El Salavador, Dodecanese Islands, Nicaragua, Central Chile

New Guinea to Albania, El Salavador, Gulf of California, Sonora, Mexico

Peru to Iran, Kuril Islands, Near Islands,  Solomon Islands,

Ecuador to Iran, Reykjanes Ridge, 

Mindanao, Philippines to Oklahoma, South Sandwich Islands.  

Loyalty Islands to South Carolina, Venezuela, Zimbabwe, Ontario, Arctic Ocean, 

Minahasa to Tristan de Cunha, Utah, Baja California, South Sandwich Is, 

Sulawesi to


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


New Britain to Kansas, Baffin Bay, Iran, Michoacan, Jalisco, Mexico,  Greenland Sea, Mayotte, Southern Colorado, Iran, Gulf of Aden, Caucasus, Arctic Ocean, Idaho, Montana, Nevada, Oklahoma,

New Guinea to Nevada, Madagascar, Jalisco, Oklahoma, South Pacific, East Central Pacific Rise, Alberta, California, Owen Ridge, Idaho, 

Peru to Albania, Greenland Sea, Ukraine, Fiji, New Zealand, Dodecanese Islands, Congo, Turkey, Unimak, Alaska, Fiji, Northern Alaska, Fiji, Aegean Sea, Hungary, 

Ecuador to  Ukraine, Mediterranean Sea, Severnaya Zemlya, North Island, New Zealand, Congo, South Africa, Turkey, Crete, Kermadec Islands, Rat Islands, Near Islands, Aegean Sea, Fiji,  South Africa, Ionian Sea, Macquarie Islands, Fiji, New Zealand, Crete, 

Mindanao, Philippines to Iceland, Montana, Jan Mayen, Southern, central, Northern California, Utah,

Loyalty Islands to Chiapas, Mexico, Bouvet Island, Pakistan, Peru, Oaxaca, Mexico, Mississippi, Central Chile, Nebraska, Central Colorado, Missouri, Tajikistan, Chiapas, Oaxaca, Mexico,  

Minahasa to Greece, Antarctic-Pacific Ridge, British Colombia, Ionian Sea, Sicily, Coast of Oregon, Vancouver,

Sulawesi to Sicily, Albania, Vancouver, Coast of Northern California,


Node 4 (90 degrees)


New Britain to Central, Southern California, 

New Guinea to

Peru to France, South Africa, Kodiak, Alaska, Jan Mayen Is,, 

Ecuador to Beaufort Sea, Northern Alaska, 

Mindanao, Philippines to

Loyalty Islands to SE Alaska, Rivello Gigedo Is, Southern Alaska, northern Baja California, Southern California,

Minahasa to southern Alaska, Romania, Greece, northern Alaska

Sulawesi to


Node 5 (72 degrees)


New Britain to

New Guinea to

Peru to Idaho, Northern Mid-Atlantic, Northern, Central California, 

Ecuador to Reykjanes Ridge, 

Mindanao, Philippines to

Loyalty Islands to

Minahasa to South Indian Ocean, Iran, Ural Mts, 

Sulawesi to


Node 6 (60 degrees)


New Britain to Nicobar Islands, India, 

New Guinea to

Peru to Southern Mid-Atlantic, Central California, South Sandwich Islands, 

Ecuador to Northern California, Azores, 

Loyalty Islands to

Southern Alaska to Oaxaca, Mexico, Central Peru, Fiji, Banda Sea,  

Sulawesi to


Node 7 (52 degrees)


New Britain to Sumatra, 

New Guinea to

Peru to New York, Baja California, North Atlantic Ocean, North Carolina, Drake Passage, Quebec,, 

Ecuador to Nevada, Northern Mid-Atlantic, Utah, Wyoming, Southern California, 

Komandorsky Islands to Central Luzon, Philippines, Yellowstone,

Loyalty Islands to Australia, Mindanao, 

Sulawesi to Loyalty Islands,