McKenzie did not have much access to magnetic anomaly data at Scripps. “The amount that had been published then was so small that you couldn’t do anything much with it,” said McKenzie. “Then I had the idea of using the slip vector in earthquakes. A lot of earthquakes had been studied in the north Pacific, particularly by Father William Stauder, who had listed all the slip vectors. He was interested in showing that these were caused by slip on faults, not by volcanic explosions, but there it all was.” Using a National Geographic globe with a Perspex cap, McKenzie drew the slip vectors around the Pacific and moved the cap until he could pin down the pole of rotation for the Pacific relative to North America.