Wayne R. Thatcher

Tribute to Thomas C. Hanks, a USGS geophysicist who demonstrated himself as a generous educator and pioneering scientist. Tom was one of a kind, and one of my oldest friends. We met as graduate students at Caltech in the late 1960s. He stood out from the start: very confident, had the air of a Princeton boy, and blew smoke rings with his lucky strikes. like this. His high intelligence was evident, and his intellectual curiosity was insatiable.

Cluster analysis offers an agnostic way to organize and explore features of the current GPS velocity field without reference to geologic information or physical models using information only contained in the velocity field itself. We have used cluster analysis of the Southern California Global Positioning System (GPS) velocity field to determine the partitioning of Pacific-North America relative motion onto major regional faults.