Page 164 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

Seismic sections recorded across a syncline
Portion
Gas Development Corporation, Pakistan.
Unmigrated and migrated
and
Oil
of Pakistan.
1987).
of the
147
al.,
permission
et
the Potwar Plateau
(Lillie
Profiles
Published with
CW-13
6.11
Reflection
FIGURE
of line
in
on

Structures
SYNCLINE
of
Appearance
FOCUS
BURIED
9
a 2 S ee ae thes tgs! hE Vente eth cftoye ect o eee. ma BER rtaiee ise Fe ee eee Sia see Ss Rate ae Rete one BSG Seer == ekg eee Sue (Fig. known are velocities 6.14b). If conversion depth accurately, thick- restores nesses perspective proper their to the On 6.14c). (Fig. the 6.15, Fig. in section time middle about appears layer of the t
iS)
v
(S) aunty janes Aepy -OM{
(s) aus Janel, ABp-OM

of (3) shows on a the diffraction, Seismic from: normal ridge seismic times of move has are section
Profiles Seismic expression line focused hyperbolic diffraction 6.12d). resulting 2) mid-ocean on travel to layer layers time
Reflection Solid the concave-upward part of the structure raypaths results (3’). Dashed line portions of the (1,2) produce crossing events that, together with (Fig. surfaces and wedge; a at appear two-way appear events middle the the though a on
Seismic 6.10 buried focus syncline. results in point; a structure appear as a “bow tie.” seen be created reflections the make 6.14a, Even interval
Of FIGURE that buried (1',2') can hummocky accretionary was a that in changes Fig. in (V,). shorter
Interpretation yjdaq yideq OW] JOABLL OUI] JOABLL «: v lows and reveal the of basement times the differences cause velocity model the layer upper a occupies
ABM-OML
ABM-OML
Tectonic ,wisemeniiie Tie" highs structural often surface oceanic in changes velocity lateral For the of layer
And Tie” 2 ene "Bow “ow that trenches the after cause in thickness, while sections. Changes that than middle
Structural N37 Section "Bow Pe a7 28S Section Collapses Synform so ties deep-sea offsetting soon formed velocities changes time Velocity (V.) the
Model Incidence Time r en, ee, Time to Back = ‘ % bow from faults that Effects in sections. Vertical of equal on down Vertical velocity thickness,
Chapter6 Syncline YW Unmigrated pom ememememememimin, Diffraction Focus Migrated Migration pemememrmenomemimey the cures profiles thrust 1) faults 6.13). (Fig. Velocity Changes layers or up higher equal of

146 V, Normal Buried Buried 2.
a) b) ¢) d)