{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}


L19_SeismicRefractionII-page3 - is the difference between...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Applied Geophysics – Refraction II Phantom arrivals 1. Shoot a long-offset shot, S L 2. The head wave traveltime curves for both shots will be parallel, offset by time T 3. Subtract T from the S L arrivals to generate fictitious 2 nd layer arrivals close to S – the phantom arrivals 4. The intercept point at S can then be determined: T i 5. Use the usual formula to determine perpendicular layer thickness beneath S 1 2 2 1 2 2 2 V V V V h T s i = Applied Geophysics – Refraction II Separation of delay times Delay time is the difference between
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: is the difference between the slant path traveltime (AB) and the traveltime along the refractor beneath (A’B) Delay time below shotpoint S: 1 2 2 1 2 2 2 1 2 1 tan cos ' V V V V h T V i h i V h T V B A V AB T A S c A c A S S − = ∆ − = ∆ − = ∆ 1 2 2 1 2 2 V V V V h T D D − = ∆ Likewise, beneath D: The delay time is related to the perpendicular depth beneath the geophone. If we know the delay time, V 1 and V 2 then we can calculate the depth....
View Full Document

{[ snackBarMessage ]}