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