TY  - RPRT
TI  - A formulation of directivity for earthquake sources using isochrone theory
AU  - Paul Spudich
AU  - Brian S.J. Chiou
AU  - Robert Graves
AU  - Nancy Collins
AU  - Paul Somerville
PY  - 2004
DO  - 10.3133/ofr20041268
UR  - https://pubs.usgs.gov/publication/ofr20041268
ID  - ofr20041268
ER  -