A formulation of directivity for earthquake sources using isochrone theory by Paul Spudich and others Created 2026-10-24 Updated 2026-11-05
United States Geological Survey Open-File Report 2004-1268. Paul Spudich and coauthors derive a finite-source directivity measure from the distribution of arrival times across a rupturing fault. The explanatory discussion links apparent pulse compression to the rate at which radiation from successive patches reaches a receiver. pubs.usgs.gov/of/2004/1268/of2004-1268tagged.pdf
Paul Spudich Created 2026-10-25 Updated 2026-11-05
Paul Spudich coauthored a description of rupture directivity based on arrival-time contours across a finite earthquake source. If a rupture advances toward a receiver, seismic waves from successively rupturing patches can arrive over a compressed interval; retreating rupture spreads those arrivals out. The formulation makes this directional pulse concentration depend on source geometry and rupture timing, supplying a physical measure for interpreting strong ground motion.[ref]
A formulation of directivity for earthquake sources using isochrone theory by Paul Spudich and others. 2004 report, finite-source isochrone formulation and directivity interpretation
Geophysicist and author of primary studies of earthquake ground motion and rupture directivity. His authorship and USGS affiliation are documented on the 2004 report: pubs.usgs.gov/of/2004/1268/ .