The Piritu cluster is named for a town in the state of Falcón, in
northwestern Venezuela (there are several other towns named Piritu in
other states). It contains one magnitude 6.0 Ms event, the Boca del
Tocuyo earthquake on April 30, 1989, and several events with magnitudes
5.0-5.9. Station distribution for direct calibration is good, but it was
necessary to retain many smaller events that are observed only to
near-regional distances to obtain good statistical power. All events
have depth control, mainly from near-source and local-distance readings,
but earlier, larger events are often constrained by teleseismic depth
phases.
