Introduction to GeophysicsAli Onceloncel@kfupm.edu.saDepartment of Earth SciencesKFU!Seismic Reflection: Acquisiton, Processing, and Waveform AnalysisIntroduction to Geophysics"KFU

!#e$ie%& 'ra$el"'ime (ur$esMeasurable features in the shot record21222 112V VV Vh112VhXcrit (Critical distance) - distance at which first head wave arrive at surfaceXcross (Cross-over distance) - is point at which head wave overtakes direct wave slope is 1/V1 for direct wave and 1/V2 for head wave direct wave travels at velocit V1 and head wave at V2!ntercept ti"e ti - the ti"e at which back-e#trapolated refractor curve intersects ti"e a#is Introduction to Geophysics"KFU

!$i%& '&1 of (illieSeismic #eflection)#efraction and reflection studies are complimentary.)#efraction pro$idin* *ross crustal $elocities and thickness+ )#eflection sho%in* finer details of structure and strati*raphy.Introduction to Geophysics"KFU

!#e,uirements for successful %orks -y #eflection and #efraction#efraction re,uires that recei$ers e.tend to %ell -eyond the /cr+ so that refraction spread len*ths need to -e fi$e to ten times the depth to the deepest refractor of interest.#eflections re,uire usually $ertically arri$in* %hich is less than the /c. 'hen+ reflection spread len*ths therefore appro.imate the depth of the deepest reflector of interest.$i%& '&1 of (illieIntroduction to Geophysics"KFU

!Seismic Reflection)Since it %as de$eloped in the 0123s and 43s as a tool for oil and *as e.ploration 5etty+ 01678. )It has -een used mostly as aGeophysical 'echni,ue for) etroleum Application) In (on9unction %ith #efraction) :and and at Sea ) On a ;ariety of Scales "03