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Geology 492/692 Field Project. Hoping to put Fernley and Hazen on the Fault Map ReMi Data. Re fraction Mi crotremor (ReMi) Method. Developed to provide quick an easy site specific shaking hazard assessment. Uses microtremor noise as source. - PowerPoint PPT Presentation
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Geology 492/692 Field Geology 492/692 Field ProjectProject
Hoping to put Fernley and Hazen on the Hoping to put Fernley and Hazen on the Fault MapFault Map
ReMi DataReMi Data
ReRefraction fraction MiMicrotremor (ReMi) Methodcrotremor (ReMi) Method
• Developed to provide quick an easy site specific shaking hazard assessment.
• Uses microtremor noise as source.• Rayleigh-wave phase-velocity dispersion curves are
picked to determine the slowest surface wave velocities at any given frequency.
• Forward modeled to produce a shear-velocity-depth sounding.
• Can estimate shear velocity with 20% accuracy to depths of up to 100m.
• Average V30 can be estimated.
Using ReMi to Find Faults?Using ReMi to Find Faults?
• Theoretically possible if fault offset displaces units with observably different shear wave velocities.
• Might be able to detect rubble zones or flower structures.
• Likely not a marketable method for fault hunting.
This StudyThis Study
• Characterized V30 at 20 sites.
– 8 Northern Fernley Hills– 12 Hazen Flat
• Fernley studies conducted with 24 channel, 10 m spacing, Bison line.
• Hazen Studies conducted with a 20 Texan, 10 m spacing array.
Results (Fernley)Results (Fernley)V30 vs. Northing (Fernley: West access road)
0
100
200
300
400
500
600
700
800
4380500 4381000 4381500 4382000 4382500 4383000
Northing (m)
V3
0 (
m/s
)
V30 vs Northing (Fernley: East access road)
0
100
200
300
400
500
600
700
4380600 4380650 4380700 4380750 4380800 4380850 4380900
Northing (m)
V3
0 (
m/s
)
Results (Hazen)Results (Hazen)
V30 vs Easting (Hazen: West of canal)
0
100
200
300
400
500
600
700
800
323300 323400 323500 323600 323700 323800
Easting (m)
V3
0 (
m/s
)
V30 vs. Northing (Hazen: North section of main access road)
0
100
200
300
400
500
600
700
4377000 4377500 4378000 4378500 4379000
Northing (m)
V3
0 (
m/s
)
Data Comparison (Fernley West)Data Comparison (Fernley West)Magnetics and ReMi vs. Northing (Fernley)
50900
51000
51100
51200
51300
51400
51500
4380500 4381000 4381500 4382000 4382500 4383000 4383500
Northing (m)
Ma
gn
eti
sm
(n
T)
0
100
200
300
400
500
600
700
800
V3
0 (
m/s
)
Magnetics
ReMi
Gravity vs. ReMi (Fernley)
2548.6
2548.8
2549
2549.2
2549.4
2549.6
2549.8
2550
2550.2
2550.4
2550.6
4380500 4381000 4381500 4382000 4382500 4383000 4383500
Northing (UTM)
Bo
ug
ue
r A
no
ma
ly (
mG
al)
0
100
200
300
400
500
600
700
800
V3
0 (
m/s
)
Gravity
ReMi
EM and ReMi Data vs. Northing
0
50
100
150
200
250
300
4380500 4381000 4381500 4382000 4382500 4383000 4383500
Northing (m)
Ap
pa
ren
t R
es
isti
vit
y (
Oh
m m
)
0
100
200
300
400
500
600
700
800
V3
0 (
m/s
)
EM
ReMi
Data Comparison (Fernley East)Data Comparison (Fernley East)Magnetics and ReMi vs. Northing
51700
51800
51900
52000
52100
52200
52300
52400
52500
4379500 4380000 4380500 4381000 4381500 4382000 4382500 4383000 4383500
Northing (m)
Ma
gn
eti
sm
(n
T)
0
100
200
300
400
500
600
700
v3
0 (
m/s
)
Magnetics
ReMi
EM and ReMi vs. Northing (Line 2)
0
50
100
150
200
250
4380000 4380500 4381000 4381500 4382000 4382500 4383000 4383500
Northing (m)
Ap
pa
ren
t R
es
isti
vit
y (
Oh
m m
)
0
100
200
300
400
500
600
700
V3
0 (
m/s
)
EM
ReMi
Gravity vs. ReMi (Fernley East)
2549
2549.5
2550
2550.5
2551
2551.5
2552
2552.5
4379500 4380000 4380500 4381000 4381500 4382000 4382500 4383000 4383500
Northing (UTM)
Bo
ug
uer
An
om
aly
(mG
al)
0
100
200
300
400
500
600
700
V30
(m
/s)
Gravity
ReMi
Data Comparison (Hazen South)Data Comparison (Hazen South)
Gravity vs. ReMi (Hazen South)
2558.4
2558.5
2558.6
2558.7
2558.8
2558.9
2559
2559.1
2559.2
2559.3
323300 323400 323500 323600 323700 323800 323900 324000
Easting UTM (m)
Sim
ple
Bo
ug
ue
r A
no
mo
ly (
mG
al)
0
100
200
300
400
500
600
700
800
V3
0 (
m/s
)
Gravity
ReMi
EM vs ReMi (Hazen South)
0
50
100
150
200
250
300
350
323300 323400 323500 323600 323700 323800 323900
Easting (m)
Ap
pa
ren
t R
es
isti
vit
y (
Oh
m-m
)
0
100
200
300
400
500
600
700
800
V3
0 (
m/s
)
EM
ReMi
Magnetics vs ReMi (Hazen South)
0.0
200.0
400.0
600.0
800.0
1000.0
1200.0
1400.0
1600.0
1800.0
2000.0
323200 323300 323400 323500 323600 323700 323800 323900 324000 324100
Easting (m)
Ma
gn
eti
sm
(n
T)
0
100
200
300
400
500
600
700
800
V3
0 (
m/s
)
Magnetics
ReMi
Data Comparison (Hazen North)Data Comparison (Hazen North)
Gravity vs. ReMi (Hazen North)
2555
2555.5
2556
2556.5
2557
2557.5
2558
2558.5
2559
2559.5
2560
4376500 4377000 4377500 4378000 4378500 4379000 4379500
Northing (m)
Sim
ple
Bo
ug
ue
r A
no
mo
ly (
mG
al)
0
100
200
300
400
500
600
700V
30
(m
/s)
Gravity
ReMi
Magnetics vs ReMi (Hazen North)
0.0
500.0
1000.0
1500.0
2000.0
2500.0
4377000 4377200 4377400 4377600 4377800 4378000 4378200 4378400 4378600 4378800 4379000 4379200
Northing (m)
Ma
gn
eti
sm
(n
T)
0
100
200
300
400
500
600
700
V3
0 (
m/s
)
Magnetics
ReMi
EM vs. ReMi
0
50
100
150
200
250
300
350
4377000 4377500 4378000 4378500 4379000 4379500
Northing (m)
Ap
pa
rre
nt
Re
sis
tiv
ity
(O
hm
-m)
0
100
200
300
400
500
600
700
V3
0 (
m/s
)
Magnetics
ReMi