GEOL 412 Lecture Notes - Lecture 6: Refraction, Seismic Source, Tx1

• School: College of Charleston
• Department: Geology and Environmental Geosciences
• Course: GEOL 412
• Professor: Jaume'

Document Summary

Trfr= (2h1cos ic/v1) + x/v2 h1= thickness of 1st layer. Ic= critical angle x = total horizontal distance. Trfr= (2h1cos i/v1) + (2h2cos ic/v2) + x/v3 h1& h2= layer thickness. Ic= critical angle btw v2& v3 x = total horizontal distance. Just add another (2hxcos i/vx) for each new layer! To find layer thickness h2, first solve for h1, then use 2nd intercept time ti2ti2= (2h1cos i/v1) + (2h2cos ic/v2) Let tx1= (2h1cos i/v1) h2= {(ti2 tx1) v2} / 2 cos ic. If layer boundaries are not horizontal, the apparent velocity of the lower layer will be faster/slower than the real velocity. Seismic refraction survey with a source on both ends of line. The apparent velocity for v2 will be different depending upon whether source is at e or g. Apparent velocity of v2is faster in up-dip direction(v2u) and slower in down-dip direction(v2d) However, total travel time from one end of the line to the other (reciprocal time)