Page 160 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

143
Profiles
hyperbolic pattern.
Reflection
on
Structures
OUIL] JOABLL
ABM-OM],
ABM-OML
of

Appearance
Section
Migrates
@
Point
Time
ee
Hyperbolic hs
to
Diffraction
Unmigrated
Back
&) Seismic expression 6.7 FIGURE of the Model Diffraction Source Point is equivalent sphere top of a very small to diffraction, producing a source point a yideq Raypaths Incidence Normal b) yideq Diffraction Section Time Migrated OUI] JOABLL Small Very subsurface the in point A Diffraction) (Point-Source Sphere can be normal sphere, leading to small very a
c)
d)

Profiles (semicircle arcs swinging by defined relationships of point each migrated the 3) points; is event make to inci- normal its from cuts it and has event shortens, steepens, interfaces. Seismic expression of line) connecting interfaces (dashed lines).
Reflection hemisphere 6.5a). as is segment Notice 1) 6.5c): the of point migrated unmigrated tends thus shorter. The downdip be, should the where horizontal (solid
Seismic a (Fig. envisioned the 6.5b). (Fig. the 4) profile become Interfaces appears it than gap a touch. Migration the 6.6 dipping interface two horizontal
Of on event be can of position (Fig. arcs event corresponding corresponding event; seismic and event time is there FIGURE ay
Interpretation anywhere from the through segment migrated of the the of the than migrated a Migrating steepen, Horizontal dipping a in deeper is direction, should it belongs, connecting yideq yjdeq OUI] JOABLL OUI] JOABLL
ACM-OML
ABf-OM 1
Tectonic been drawn reflection event. The each to positions from downdip deeper are the than event. updip, shallow, Two Connecting that illustrate event updip event it where anaziisieestaal Vp

And have structure) linear the tangent migrated is points steep 6.6 unmigrated the In horizontal to updip
Structural trace could a of along running and event unmigrated less is event migrated move Interface Fig. in events. the from event Model Section

seismic two-dimensional Migration points segment unmigrated the segments raypaths position. The horizontal the Interface Time
6 unmigrated 2) than Dipping away moves
Chapter the on for through line the the of the event; unmigrated longer reflecting dence actual across moved and Dipping Vy Normal Unmigrated

142 a) b) c)