A tribute to George Plafker

In a long and distinguished career, George Plafker has made fundamental advances in understanding of megathrust tectonics, tsunami generation, paleoseismology, crustal neotectonics, and Alaskan geology, all by means of geological field observations. George discovered that giant earthquakes result from tens of meters of seismic slip on subduction thrusts, and he did this before the theory of plate tectonics had become a paradigm. The discovery was founded on George's comprehensive mapping of land-level changes in the aftermath of the 1964 earthquake in Alaska, and on his similar mapping in the region of the 1960 earthquakes in Chile. The mapping showed paired, parallel belts of coseismic uplift largely offshore and coseismic subsidence mostly onshore -- a pattern now familiar as the initial condition assumed in computer simulations of subduction-zone tsunamis. George recognized, moreover, that splay faulting can play a major role in tsunami generation, and he also distinguished carefully between tectonic and landslide sources for the multiple tsunamis that accounted for nearly all the fatalities associated with the 1964 Alaska earthquake. George's classic monographs on the 1964 earthquake include findings about subduction-zone paleoseismology that he soon extended to include stratigraphic evidence for cyclic vertical deformation at the Copper River delta, as well as recurrent uplift evidenced by flights of marine terraces at Middleton Island. As a geologist of earthquakes, George also clarified the tectonics and hazards of crustal faulting in Alaska, California, and overseas. All the while, George was mapping bedrock geology in Alaska, where he contributed importantly to today's understanding of of how terranes were accreted and modified.