Deep‐focus earthquakes—Earthquakes with extremely deep loci occur in well‐defined areas. The deepest foci, 600 km and more, are to be found in Japan, the Philippines, the Moluccas, and the Java Sea, in the Polynesian Archipelago, and in South America. Everywhere they are situated along an inclined surface, from the borders of the ocean sloping down below the continents. The slope of this surface is 30° to 40°.