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Megan R.M. Brown1,2 and Dr. Mian Liu2
1 Department of Geological Sciences, University of Colorado Boulder2 Department of Geological Sciences, University of Missouri – Columbia
Injection-Induced Seismicity in
central Utah
Induced Seismicity
Quarry induced
Mining induced
Reservoir induced
Fluid injection induced
McGarr et al., 2002
National Research Council of the National Academies, 2013
Induced Seismicity
Quarry induced
Mining induced
Reservoir induced
Fluid injection induced
McGarr et al., 2002
National Research Council of the National Academies, 2013
Fluid Injection Induced Earthquakes
Enhanced Recovery
Geothermal
Wastewater Disposal
Ellsworth, 2013
Why Utah?
Seismicity
Oil & Gas Production Underground Coal Mining (< 960 m)
R² = 0.9749
0
100
200
300
May-1979 Jan-1993 Oct-2006 Jun-2020
Eart
hq
uak
es
Date
Area 1: Cumulative Earthquakes
R² = 0.9816
0
20
40
60
80
May-1979 Jan-1993 Oct-2006 Jun-2020
Eart
hq
uak
es
Date
Area 2: Cumulative Earthquakes
R² = 0.8846
0
5
10
15
May-1979 Jan-1993 Oct-2006 Jun-2020
Eart
hq
uak
es
Date
Area 4: Cumulative Earthquakes
Area 4
Variation in seismicity rate
Very small sample size
No conclusions can be made
Significant seismicity rate increase in
late 1990s
Active coal mining area
Seismicity in the area has been
inferred as mining induced seismicity
(MIS)
R² = 0.9066
0
5,000
10,000
15,000
20,000
May-1979 Jan-1993 Oct-2006 Jun-2020
Eart
hq
uak
es
Date
Area 3: Cumulative Earthquakes
Wastewater Disposal Wells
32 Active wells
27 inject into the Navajo aquifer (Navajo Ss, Kayenta Fm, and Wingate Ss)
Is the seismicity entirely mining induced seismicity?
Or, is it induced by the wastewater injection?
0.0E+00
5.0E+07
1.0E+08
1.5E+08
2.0E+08
2.5E+08
3.0E+08
3.5E+08
4.0E+08
4.5E+08
0
5,000
10,000
15,000
20,000
Jul-1979 May-1986 Mar-1993 Jan-2000 Nov-2006 Oct-2013 Aug-2020
Inje
ctio
n V
olu
me
(bb
ls)
Eart
hq
uak
es
Date
Area 3 Cumulative Earthquakes and Injection Volume
Seismicity Injection Volume
Area of Increased
Seismicity
C1
C2
0.E+00
1.E+07
2.E+07
3.E+07
4.E+07
5.E+07
6.E+07
7.E+07
8.E+07
0
750
1,500
2,250
3,000
3,750
May-79 Jan-93 Oct-06 Jun-20
Inje
ctio
n V
olu
me
(bb
ls)
Eart
hq
uak
e C
ou
nt
Date
Cluster 1: Cumulative Earthquakes
and Well Injection Volume
Seismicity
Injection Volume
0.E+00
1.E+07
2.E+07
3.E+07
4.E+07
5.E+07
6.E+07
7.E+07
0
1,000
2,000
3,000
May-79 Jan-93 Oct-06 Jun-20
Inje
ctio
n V
olu
me
(bb
ls)
Eart
hq
uak
es
Date
Cluster 2: Cumulative Earthquakes
and Well Injection Volume
Seismicity
Injection
Volume
Coal Production
R² = 0.993
0.0E+00
1.0E+08
2.0E+08
3.0E+08
4.0E+08
Co
al
Pro
du
ctio
n (
Sh
ort
To
ns)
Year
Annual Coal Production Area 3
R² = 0.9708
0.E+00
3.E+07
5.E+07
8.E+07
1.E+08
Co
al
Pro
du
ctio
n (
Sh
ort
To
ns)
Year
Annual Coal Production Cluster 1
R² = 0.9821
0.0E+00
5.0E+07
1.0E+08
1.5E+08
2.0E+08
2.5E+08
Co
al
Pro
du
ctio
n (
Sh
ort
To
ns)
Year
Annual Coal Production Cluster 2
Mine Safety and Health Administration
(http://www.msha.gov/OpenGovernmentData/OGIMSHA.asp)
Coal Production,
Injection Volume,
& Seismicity
0
5,000
10,000
15,000
20,000
25,000
0.E+00
1.E+08
2.E+08
3.E+08
4.E+08
5.E+08
Ea
rth
qu
ak
es
Co
al
Pro
du
ctio
n (
Sh
ort
To
ns)
an
d W
ell
Vo
lum
es (
bb
ls)
Year
Area 3
Coal Production
Well Volumes
Seismicity
Steady coal
production rate
since 1983
Injection rate
appears better
correlated with
seismicity rate
variations
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
0.0E+00
2.0E+06
4.0E+06
6.0E+06
8.0E+06
1.0E+07
1.2E+07
1.4E+07
1.6E+07
1.8E+07
Ea
rth
qu
ak
es
Co
al
Pro
du
ctio
n (
Sh
ort
To
ns)
Year
Annual Coal Production
Annual Earthquakes
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
0.0E+00
5.0E+06
1.0E+07
1.5E+07
2.0E+07
2.5E+07
3.0E+07
3.5E+07
Ea
rth
qu
ak
es
Wel
l V
olu
mes
(b
bls
)
Year
Annual Well Volumes
Annual Earthquakes
Coal Production, Injection Volume, & Seismicity
Hypothesis:
Increased seismicity is
injection-induced
seismicity caused by pore-
pressure increase along
pre-existing faults.
Cluster 1
0
500
1,000
1,500
2,000
2,500
3,000
3,500
0.E+00
2.E+07
4.E+07
6.E+07
8.E+07
1.E+08
Ea
rth
qu
ak
es
Co
al
Pro
du
ctio
n (
Sh
ort
To
ns)
an
d W
ell
Vo
lum
es (
bb
ls)
Year
Coal Production
Well Volumes
Seismicity
0
100
200
300
400
500
600
700
800
900
0.E+00
1.E+06
2.E+06
3.E+06
4.E+06
5.E+06
6.E+06
7.E+06
Ea
rth
qu
ak
es
Co
al
Pro
du
ctio
n (
Sh
ort
To
ns)
Year
Annual Coal Production
Annual Earthquakes
0
100
200
300
400
500
600
700
800
900
0.E+00
1.E+06
2.E+06
3.E+06
4.E+06
5.E+06
6.E+06
7.E+06
8.E+06
Ea
rth
qu
ak
es
Wel
l V
olu
mes
(b
bls
)
Year
Annual Well Volumes
Annual Earthquakes
Cluster 2
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
0.0E+00
5.0E+07
1.0E+08
1.5E+08
2.0E+08
2.5E+08
Ea
rth
qu
ak
es
Co
al
Pro
du
ctio
n (
Sh
ort
To
ns)
an
d W
ell
Vo
lum
es (
bb
ls)
Year
Coal Production
Well Volumes
Seismicity
0
200
400
600
800
1,000
1,200
1,400
1,600
0.0E+00
2.0E+06
4.0E+06
6.0E+06
8.0E+06
1.0E+07
1.2E+07
1.4E+07
Ea
rth
qu
ak
es
Co
al
Pro
du
ctio
n (
Sh
ort
To
ns)
Year
Annual Coal Production
Annual Earthquakes
0
200
400
600
800
1,000
1,200
1,400
1,600
0.0E+00
1.0E+06
2.0E+06
3.0E+06
4.0E+06
5.0E+06
6.0E+06
Ea
rth
qu
ak
es
Wel
l V
olu
mes
(b
bls
)
Year
Annual Well Volume
Annual Earthquakes
C1
C2
Spatial Correlation
Spatial Correlation
Pore-Pressure Increase
Can injection raise pore-
pressure sufficiently to induce
the increased seismicity?
≥ 0.01 MPa may induced
seismicity (King et al., 1994)
Approximately 1 m change
in hydraulic head
10 – 12 km
1 – 5 year time gap
Analytical Model
Theis Solution
Numerical Model
Groundwater Modeling
System (GMS)
MODFLOW 2000
Theis (1935) Equation
Isotropic, homogeneous flow
Confined aquifer
Injection well – constant
injection rate
Use published transmissivity
and storativity values
Use change in hydraulic head
to calculate change in pore
pressure
Δh – change in hydraulic head
r – distance from the well
t – time since injection started
Q – injection rate
T – transmissivity
S – Storativity
u – dimensionless time parameter
x – variable of integration
∆h r, t =Q
4πT u
∞ e−xdx
x
𝑢 =𝑟2𝑆
4𝑇𝑡
Analytical Groundwater Model
Theis Analytical Solution
Transmissivity (T) values and storativity (S) values are (A) T = 125 m2 day-1, S = 0.0003; (B) T = 125 m2
day-1, S = 0.008; (C) T = 400 m2 day-1, S = 0.0003; and (D) T = 400 m2 day-1, S = 0.008.
Numerical Groundwater Model
One layer, 3° dipping
grid model
GMS
MODFLOW 2000
Isotropic, homogeneous
flow
Confined aquifer
Parameters same as in
analytical solution
Results shown in down-
dip direction
Magnitude Distribution
0
1
2
3
4
-0.5 0 0.5 1 1.5 2 2.5 3
Lo
g(N
)
Magnitude
Testing for changes in background seismicity
Temporal changes in the magnitude-frequency relationship (Gutenberg & Richter, 1944) prior to and following the start of injection. b-value can be used as a stress indicator
Log10(N) = a - bM
N = number of cumulative events of magnitude M or larger
a and b are constants
b-values
Area 3
Increase in b-value post-injection
y = -1.1438x + 5.2203
R² = 0.9609
0
1
2
3
4
-0.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5
Lo
g(N
)
Magnitude
Area 3: Pre-Injection
y = -1.4873x + 5.8332
R² = 0.9502
0
1
2
3
4
5
-1 0 1 2 3 4 5
Lo
g(N
)
Magnitude
Area 3: Post-Injection
Cluster 1
Significant increase in b-value
following the start of injection
y = -1.3706x + 5.2689
R² = 0.9884
0
1
2
3
0 1 2 3 4 5
Lo
g(N
)
Magnitude
Cluster 1: Pre-Injection
y = -2.3154x + 6.4687
R² = 0.9926
0
1
2
3
4
-0.5 0 0.5 1 1.5 2 2.5 3
Lo
g(N
)
Magnitude
Cluster 1: Post-Injection
b-values
Cluster 2
Consistent b-value pre- and post-
injection
y = -1.5583x + 6.0108
R² = 0.9896
0
1
2
3
4
0 1 2 3 4
Log(N
)
Magnitude
Cluster 2: Pre-Injection
y = -1.5167x + 4.8925
R² = 0.8581
0
1
2
3
4
-1 0 1 2 3 4
Log (
N)
Magnitude
Cluster 2: Post-Injection
b-values
Conclusion
Based on:
the temporal and spatial correlations,
groundwater modeling results, and
temporal changes in b-value,
We conclude the increased seismicity in
Area 3, and particularly Cluster 1, is
mining induced seismicity and
wastewater injection induced seismicity
caused by increased pore pressure
along pre-existing faults.
Questions?
Ellsworth, W. L. (2013), Injection-Induced Earthquakes, Science, 341(6142), 1225942.
Gutenberg, B., and C. F. Richter (1944), Frequency of earthquakes in California, Bulletin of the Seismological
Society of America, 34(4), 185-188.
King GCP, Stein RS, Lin J (1994) Static stress changes and the triggering of earthquakes. Bulletin of the
Seismological Society of America, 84, 935-953.
McGarr, A., D. Simpson, and L. Seeber (2002), 40 Case Histories of Induced and Triggered Seismicity,
International Geophysics Series, 81, 647-661.
National Research Council of the National Academies (2013), Induced Seismicity Potential in Energy
Technologies, 300 pp., The National Academies Press, Washington, DC.
Theis, CV (1935) The relation between the lowering of the piezometric surface and the rate and duration
of discharge of a well using ground water storage. Transactions American Geophysical Union, 2, 519-524.
References
Thank You!