The actual mechanism of earthquake generation eluded geologists until H. F. Reid of John's Hopkins University conducted a study following the great 1906 San Francisco earthquake. The earthquake was accompanied by horizontal surface displacembers of several meters along the northern portion of the San Andreas Fault. Field studies determined that during this single earthquake, the Pacific plate lurched as much as 4. 7 meters (15 feet ) northward past the adjacent North American plate.