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)


Bolivia to

New Ireland/Britain to

Banda Sea to

Papua New Guinea to Northern mid-Atlantic, 

Oaxaca, Mexico to

Honduras to

Gulf of Alaska to South Indian Ocean


Outer shadow zone edge (141-148 degrees)


Bolivia to Xizang, Xinjiang, China, PNG, Sumba, Indonesia, 

New Ireland/Britain to Azores, Portugal, Trinidad and Tobago, Virgin Islands,  

Banda Sea to northern Chile, El Salvador, Argentina, Chile, 

Papua New Guinea to Mid-Atlantic, Bolivia, Haiti, Portugal, Northern Venezuela, Jamaica, Azores, Puerto Rico, Bolivia, Colombia, Virgin Islands, Dominican Republic, 

Oaxaca, Mexico to South Indian Ocean, Sumbawa, 

Honduras to Molucca Sea, Talaud Is, Banda Sea, Mauritius, Seram, Aru Indonesia, Tajikistan, Tanimbar, Myanmar, Banda, Molucca, Mindanao, Central Philippines, 

Gulf of Alaska to Namibia, Mozambique, South Indian Ocean, South Sandwich Islands, 


Node 3 (120 degrees)


Bolivia to So. Iran,

New Ireland/Britain to Michigan, El Salvador, Nicaragua, Poland, South Sandwich Is.,

Banda Sea to Southern Chile, Chile Rise, Greece, Gulf of California, England,  

Papua New Guinea to Iceland, South Sandwich Islands, Mediteranean Sea, Missouri, Albania, Oaxaca, Mexico, Oklahoma

Oaxaca, Mexico to Iran, Papua New Guinea,

Honduras to Iran, Mozambique, Guam, Antarctica, Kyrgyzstan,  Northern Mariana Islands, Southern Iran, Hindu Kush, Tajikistan, Bonin Is,  Kyushu, Tajikistan,  

Gulf of Alaska to Ascension Is, Balleny Is, Antarctica,  


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


Bolivia to Turkey, Gulf of Alaska, Tonga, Fiji, Yukon, Canada,   

New Ireland/Britain to South Indian Ocean, Nebraska, Gulf of California, Iran, Iraq, South Chile Rise,  Mexico, South Pacific, Jalisco, Mexico

Banda Sea to Vancouver, Turkey, Caucasus,

Papua New Guinea to Montana, Yellowstone, Gulf of California, Southern California, Caucasus, Idaho, Ethiopia, Tanzania, Gulf of California, Alberta, Montana, West Chile Rise, Mozambique, Eastern Turkey, Baffin Bay, Tanzania, Idaho, Gulf of California, Easter Island, SW Russia, Utah, Yellowstone, Sonora, Mexico, Southern California,  

Oaxaca, Mexico to Izu Islands, Mediterranean Sea, Santa Cruz Is. Bulgaria, Greece, Ionian Sea, Honshu, Japan, 

Honduras to Tonga, Fiji, Kermadec Is, Namibia, Kuril Islands, Eastern Turkey, Honshu, Japan, Antarctica, South Indian Ocean, Tonga, Kermadec Islands, Kurils,  Iran-Iraq border, Fiji, North Is. New Zealand, Fiji, Tonga,  Hokkaido, Japan, 

Gulf of Alaska to Tarapaca, Chile, Bolivia, South Island, New Zealand, Ethiopia, Tanzania, Gulf of Aden, Northern Chile, South Chile Rise, Java, Bolivia, Sumatra, North Island, New Zealand, northern Chile, Bali, Indonesia, Sumatra, Central mid-Atlantic, Cook Strait, New Zealand, Central  Chile, Nicobar Islands, Australia, Java, Sumatra, Tarapaca, Chile,  


Node 4 (90 degrees)


Bolivia to

New Ireland/Britain to Nevada, Central, Southern California, 

Banda Sea to Gulf of Alaska,

Papua New Guinea to Vancouver, Iran, 

Oaxaca, Mexico to Central Atlantic, Kuril Islands, France, Kermadec Is, 

Honduras to South Atlantic Ridge, Romania, South Sandwich Is, Greece, Kamchatka, 

Gulf of Alaska to Central Peru, Banda Sea, Sulawesi, Papua New Guinea, Iran, Myanmar, Kermadec Is, Molucca, Banda,  


Node 5 (72 degrees)


Bolivia to Nebraska,

New Ireland/Britain to

Banda Sea to

Papua New Guinea to China, Indian Ocean, Unimak, Alaska, Fox Islands,

Oaxaca, Mexico to Iceland, Andreanof Islands,

Honduras to Wales, France, North of Svalbard, Arctic Ocean,

Gulf of Alaska to Virgin Islands, Chiapas, Mexico, Galapagos, China, Poland, Puerto Rico, Netherlands Antilles, Virgin Islands, Central Pacific Ocean, Colombia, Tajikistan, China, France, Virgin Islands, Taiwan, Kazakhstan, South of Panama, Xinjiang, China,


Node 6 (60 degrees)


Bolivia to Central Atlantic, Oaxaca, Guerrero, Mexico, Gulf of California, Tennessee,  

New Ireland/Britain to Myanmar, Kamchatka, Andreanof Islands, 

Banda Sea to South Island, New Zealand,

Papua New Guinea to Kuril Islands,

Oaxaca, Mexico to Northern Mid-Atlantic, Alaska Peninsula, Baffin Bay,  

Honduras to Gulf of Alaska,  West Chile Rise,

Gulf of Alaska to Kyushu, Japan, Northern Marianas, El Salvador, Guatemala, Honduras, Reykjanes Ridge, Chiapas, Mexico,


Node 7 (52 degrees)


Bolivia to Guerrero, Mexico,

New Ireland/Britain to

Banda Sea to Fiji,

Papua New Guinea to Macquarie Island, Myanmar, Kuril Islands,

Oaxaca, Mexico to

Honduras to Azores, Easter Island, Central Chile, Reykjanes Ridge,

Gulf of Alaska to South Carolina, Izu, Honshu, Japan, Iceland, Maine, Guerrero, Michoacan, Mexico,


Node 8 (45 degrees)


Bolivia to

New Ireland/Britain to

Banda Sea to

Papua New Guinea to Sumatra, Japan,  Tonga, New Zealand,  

Oaxaca, Mexico to

Honduras to Coast of Oregon, northern Mid-Atlantic,  

Gulf of Alaska to Michigan, Maine, Durango, Mexico, Quebec, Hokkaido, Japan


Node 10 (36 degrees)


Bolivia to

New Ireland/Britain to

Banda Sea to

Papua New Guinea to Java, Taiwan, Ryukyu Islands, Kyushu, Izu Is, Japan, 

Oaxaca, Mexico to San Francisco, California, Yellowstone NP,


Node 12 (30 degrees)


Bolivia to

New Ireland to/Britain

Oaxaca, Mexico to San Francisco, California, Yellowstone NP,