land seismic-enying ridge region
Post on 06-Jan-2016
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Land Seismic-Enying Ridge Region
Processing• Plus Minus Method
• Minus time, T- =tAG-tBG
• Plus time, T+ =tAG+tBG-tAB
• Depth, 21
22
21
2 VV
VVTZ
Refraction
Reflection
Interpretation•No Correlation with Resistivity data.•Layer 1 is likely to be unconsolidated soil.•Topography caused by erosion, which did not affect
the refracted layer.
Conclusion•The Aim of the Refraction survey was to compare the subsurface structure to the topography. The results suggested that the two are not correlated. The topography is likely to be an erosional structure, rather than a result of tectonic activity.
•The 500m reflection survey revealed, a SSW dipping basement horizon from 45 to 75m depth.
Interpretation•Gravity and Magnetic gradients correlate to the dip of the reflector. This indicates that
the basement rock is shallower at the NNE end. •Depth of bright reflector correlates well with the depth of the basement from the
borehole.•Some sediment onlap onto the basement.
VLF
Roisin McGee1
Brioch Hemmings1
Ali Al-Ibrahim1
Deák Attila2
Komoróczi Zoltán2
Line 1&2(R&R)
Line 3&4(R&R)
Line 6 (Refraction)
Line 7(Reflection)
Line 5(Refraction)
Introduction
Processing - ProMax
Results (Line 6)•Change in Velocity at 20m depth•Unlikely correlation with topography.•Slight lateral variation in Velocity
105
110
115
120
125
130
135
140
145
150
155
0 100 200 300 400 500 600
Distance (m)
Hei
gh
t ab
ove
sea
leve
l (m
)
topography
Refractor topoV1=0.37 V1=0.37 V1=0.42 V1=0.43 V1=0.40 V1=0.42
V2=1.82 V2=1.75 V2=1.93 V2=1.51 V2=1.77 V2=1.65
ENE WSW
Method
Method
Bj38
Ref
lect
ion
lin
e 7
Results (Line 7)•Bright Reflector found at about 75m•Dipping to the SSW•No topographic correlation
SSW
Load data
Geometry
Edit
Amplitude Recovery
Mute
Elevationstatics
Filter test & Velocity Hyperbola
CDP sort
Brute Stack
Velocity Analysis
Stack
Bore hole data
Magnetics
-8
-7
-6
-5
-4
-3
-2
0 100 200 300 400 500 600 700
Distance.m
Mag
netic
s/n
T
Gravity
3.5
3.7
3.9
4.1
4.3
4.5
4.7
4.9
5.1
5.3
5.5
0 100 200 300 400 500 600 700
Distance/m
Gravit
y/m
Gal Gravity gradient
Magnetic gradient
•The first aim was to learn the methods of seismic Reflection and Refraction surveying, processing and interpretation.
•Refraction was used at the fields near Enying, to image the geological structure and relate it to the topography.
•Reflection survey was implemented at an area North-East of Enying Ridge, to inspect the structure of the basement.
NNE
1.Leeds University, 2.Eötvös University
A
B
1
2
3
1
2
3
• The Aim of the Refraction survey was to compare the subsurface structure to the topography, and it was proven that the two are not correlated.
• The Basement was imaged, using a reflection survey, and the shallow geological structure was revealed.
• Basement is at ….depth
V1
V2
Dep
th
Shot point
Geophone
Dep
th V1
V2
A BG
SP1SP2
24 geophones
24 geophones1
2
Load data
Geometry
Edit
Amplitude Recovery
Mute
Elevationstatics
Filter test & Velocity Hyperbola
CDP sort
Brute Stack
Velocity Analysis
Stack
Load data
Geometry
Edit
Amplitude Recovery
Mute
Elevationstatics
Filter test & Velocity Hyperbola
CDP sort
Brute Stack
Velocity Analysis
Stack
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