1. n. [Geophysics]
The earliest arrival of energy propagated from the energy source at the surface to the geophone in the wellbore in vertical seismic profiles and check-shot surveys, or the first indication of seismic energy on a trace. On land, first breaks commonly represent the base of weathering and are useful in making static corrections.
See related terms: base of weathering, check-shot survey, first break, static correction, suppression, vertical seismic profile