They can each cause a tidal wave across the entire North American coast line.
Not only that, the tidal wave would reach up into the Hudson Bay, swap over into the northern side of South America and echo back toward the Iceland, Greenland, Norway, England, Spanish areas, continue into the Mediteranean Sea towards Italy, Greece, Corsica, Sicily, Malta and slowly reach into Lebanon and Israel.
There are about 200 million people in Europe in danger, 100 million in North America, 300-400 million in South America and another 400 million in the Mediteranean Sea surrounding nations. The catastrophe would change the face of the earth, destroy 80% of the worlds industrial capacity and bring the Gulf Stream to a standstill which would change the weather for the entire northern hemisphere forever. The warm water which keeps Europe from freezing all the time would be gone.
Probably only the preppers, Aborigines, African bushmen, Eskimos and the plains living peoples of central Europe would have a chance of rebuilding and surviving.
AND THAT IS IF: HE ONLY USES ONE ON THE ATLANTIC COAST.....THE PACIFIC COAST WOULD DOUBLE THE PROBLEMS: Your chances of survival dwindle to minimal. Get right with your God people and live free, Gary