S51D-1800
Dependency of near field ground motions on the structural maturity of the ruptured fault
M. Radiguet , F. Cotton , I. Manighetti , M. Campillo , J. Douglas
(1)
(1)
(1)
(1)
(2)
contact: [email protected]
(1)Laboratoire de Géophysique interne et de tectonophysique, Univ. J. Fourier, Maison des Géosciences, BP 53, 38041 Grenoble Cedex 9, FRANCE
(2) BRGM - ARN/RIS, 3 avenue C. Guillemin, BP 36009, 45060 Orleans Cedex 2, FRANCE
Goal
Results
1. Residuals for individuals earthquakes
0.5
N. Palm Springs (17)
Coyote Lake (3)
Loma Prieta (29)
Izmit (10)
Landers (12)
San Fernando (18)
USA
India
Turkey
5.6 Reverse 6.8 Reverse buried
6.6 Strike-slip surface
19 28/06/1992 Landers
USA
7.3 Strike-slip surface
20
21
22
23
24
25
26
27
28
USA
Japan
Turkey
Taiwan
USA
Turkey
USA
USA
USA
6.6
6.9
7.6
7.6
7.1
7.1
7.8
6.6
6
17/01/1994
16/01/1995
17/08/1999
20/09/1999
16/10/1999
12/11/1999
03/11/2002
22/12/2003
28/09/2004
Northridge
Kobe
Izmit
Chi-Chi
Hector Mine
Duzce
Denali
San Simeon
Parkfield
Reverse
Strike-slip
Strike-slip
Reverse
Strike-slip
Strike-slip
Strike-slip
Reverse
Strike-slip
buried
surface
surface
surface
surface
surface
buried
-
L(km)
<200
~10
<100
200
> 300
~20
~110
200
~60
~100
~100
~10
<100
15-20
>1000
1000-1500
I-Age D total
Matu
(Ma)
(km) MR (cm/an) rity
6
~0.5
1
<0.1
1
0.01
1
1
24 1.5 +/- 0.4
2
24
1.5-2
2
~ 0.1
1
0.1-0.2
1
24 1.5 +/- 0.4
2
small
1
<0.2
1
0.05-0.12
1
0.1-0.2
1
2-4
10
0.17-0.53
1
0.3
1
<0.1
11-13
~100
1.5-3
-0.5
0.1
1
pga
0.1
1
(e) Mature faults
Erzincan (3)
0.5
0.5
Mammoth Lakes (3)
Parkfield (36)
Hector Mine (4)
Denali (3)
San Simeon (4)
Santa Barbara (4)
Tabas (3)
Residual
Fault name
Transverse Ranges fault zone: San Fernando fault
Sierra Nevada
fault system:small,
secondary
fault
Western
Transverse
range fault zone:
small secondary
fault
North ending of Nayband fault: Tabas fault
Calaveras fault
Imperial Valley fault (south part of San Jacinto fault)
Hilton Creek fault zone
Coalinga thrust fault
Calaveras fault
south Mackenzie Fold Belt: English Chief Anticline
San Gorgonio Fault zone: Banning and Garnet Hill faults
White mountain fault zone
Edgecumbe fault (Whakatane graben)
Transverse Ranges fault zone: Elysian park Thrust
Sargent fault
Transverse Range region, sierra madre fault zone,
Clamshell-Sawpit faults
Main Central Thrust zone
Central section of North Anatolian Fault
Eastern California Schear zone: Johnson Valley-EmersonCamprock fault system
Transverse Ranges fault zone :Northridge fault (eastern
extension of Oak Ridge fault)
Nojima fault
western tip of North Anatolian fault
Chelungpu
fault Shear zone: Lavis Lake fault, Bullion
Eastern
California
fault
western tip of North Anatolian fault
Denali fault system
Oceanic fault or adjacent blind thrust
San Andreas Fault
Morgan Hill (11)
0
0
-0.5
-0.5
Nahanni (3)
pga
0.1
1
(c) Immature faults, number stations < 3
Oroville (1)
0.5
Kobe (2)
Sierra Madre (2)
Edgecumbe (2)
0
-0.5
1
3
3
Uttarkasi (11)
pga
0.1
pga
0.1
1
1
<100 2.3 - 0.5
~10
<5
1000-1500
~5
100-200
0.7
< 200
1000-1500
~5
~2000
> 30
<100
>1000
85
~14
85
~130
>150
0.05-0.1
1
0.1 - 0.5
0.05-0.1
~1.5
1.3 +/-0.5
0.05-0.1
~1.5
0.9-1.3
<0.1
~3
1
1
2
2
1
2
3
1
3
Determination of the fault structural maturity
On immature faults (best constrained plots a and b), the ground motions generated by earthquakes generally exceed the model level, while on "intermediate" and mature faults, the
ground motions are generally lower than the model level.
Analysis
We compare the observed ground motions spectral amplitudes to the ground motions prediction equations proposed by Boore et al. (1997).
Residual = log10(PSAobserved/PSABoore)
To compare the influence of fault structural maturity with other source parameters, we classify
the recorded ground motions according to: (i) the structural maturity of the broken faults, (ii)
the faulting mechanism, (iii) the existence or absence of significant surface slip. For each category defined, we averaged the residuals with two different methods:
'simple', not weighted average of residuals (following Somerville 2003)
Bias: average of residuals weighted by the number of recording stations (following
Spudich et al. 1999)
Mature
0.2
Immature
0.1
0.1
0
0
-0.1
-0.1
-0.2
-0.2
pga
0.1
(b)
1
0.2
pga
0.1
(e)
1
0.2
Strike-slip
0.1
0.1
0
0
-0.1
-0.1
-0.2
-0.2
pga
0.1
(c)
pga
1
0.2
0.1
(f)
1
Buried
0.2
Surface
0.1
0
-0.1
-0.1
-0.2
-0.2
pga
0.1
1
Period (second)
pga
0.1
1
Average of residuals
0.2
Strike-slip Mature
0.1
0.1
0
0
-0.1
-0.1
-0.2
-0.2
pga
0.1
1
Period (second)
pga
0.1
1
-0.3
The earthquakes rupturing immature faults generate ground motions larger by a factor of 1.5 than earthquakes on mature faults. By comparison, reverse faulting earthquakes generate motions 1.35 times
higher than strike-slip faulting earthquakes, and buried rupture earthquakes generate motions 1.25
times larger than surface rupturing ones.
The fault structural maturity is thus the parameter having the most influence on ground motions since it
generates the largest differences and the lowest standard deviations.
Style of faulting and fault maturity are not independent parameters: we studied the influence of fault
maturity for a constant style of faulting. When only strike slip earthquakes are considered, the earthquakes rupturing mature faults still generate ground motions higher by a factor of 1.25 than earthquakes rupturing immature faults.
Period (second)
Figure 3. Influence of fault maturity with a constant style of faulting (strike-slip). (a) Unweighted average
of residuals (approach of Somerville et al.); (b) Weighted average of residuals (approach of
Spudich et al.).
We suggest that the effect on ground motions commonly attributed to the faulting mechanism more
likely results from the fault maturity control.
Conclusions
Earthquakes rupturing mature faults produce ground motion 1.5 times higher than earthquakes on mature faults.
Among the source parameters studied, the fault structural maturity is the one having the
most influence on ground motions.
-0.3
Period (second)
0.3
Strike-slip Immature
-0.3
0.3
(b)
0.2
-0.3
0.3
Reverse
3. Influence of fault maturity for a constant style of faulting
(a)
The structural maturity is an integrated parameter determined from the following information:
total length of the long-term fault
initiation age of the fault
maximum cumulative displacement on the fault
long-term slip rate
This caused us to classify the broken faults into the three classes proposed by Manighetti et al.
(2007): (1) immature, (2) intermediate, and (3) mature.
0.3
0
Figure 1. Ratio of the response spectral amplitude
of individual eathquakes (averaged over recording
stations) to that of the GMPEs of Boore et al (1997).
The zero line represents the model of Boore et al.
(1997). 0.1 units of common logarithm equals a
factor of nearly 1.26.
Period (second)
<200
0.2
0.1
Period (second)
Biais
16 28/06/1991 Sierra Madre
17 19/10/1991 Uttarkashi
18 13/02/1992 Erzincan
Country Mw
USA
6.6
USA
6
USA
5.8
Iran
7.3
USA
5.7
USA
6.5
USA
6.2
USA
6.3
USA
6.1
Canada
6.7
USA
6
USA
6.2
USA
6.5
USA
5.9
USA
6.9
Duzce (8)
-0.5
Residual
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Date
09/02/1971
01/08/1975
13/08/1978
16/09/1978
06/08/1979
15/12/1979
25/05/1980
02/05/1983
24/04/1984
23/12/1985
08/07/1986
21/07/1986
02/03/1987
01/10/1987
18/10/1989
Chi-Chi (51)
(b) Immature faults, number stations 3-10
Table 1. List of the analyzed earthquakes, Style
with
the
characteristics
of
the
broken
faults
and
their
structural
maturity
of
EQ#
0
pga
Chalfant Valley (5)
ruptur
e
surface
surface
surface
buried
surface
buried
0
Whittier Narrows (12)
We analysed near field ground motions for 28 large (Mw 5.3-7.8) crustal earthquakes.
We considered records on rock and stiff soil sites. In total 375 records.
Style of
faulting
Reverse
Normal
Reverse
Reverse
Strike-slip
Strike-slip
Normal
Reverse
Strike-slip
Reverse
Reverse
Strike-slip
Normal
Reverse
Reverse
Imperial Valley (2)
0.5
Figure 2. (a-b-c) plots
show the unweighted
average of residuals
for events, (d-e-f) plots
show weighted average of residuals and
standard
deviation.
The source parameters considered are the
fault maturity (a-d), the
style of faulting (b-e),
and the existence of
abscence of surface
break (c-f).
(d)
(a)
The reduction of ground motions with increasing fault maturity is coherent with a lower stress
drop for earthquakes on mature faults than on immature faults. The stress drop difference would
result from the reduction of the strength and friction on the fault plane as the fault accumulates
more slip.
References
Anderson, J. G., S. G. Wesnousky, and M. W. Stirling (1996). Earthquake size as a function of fault slip rate, Bull. Seism. Soc. Am. 86, 683–690.
Kagawa, T., K. Irikua, and P. G. Somerville (2004). Differences in ground motion and fault rupture between the surface and buried rupture earthquakes, Earth Planets Space 56, 3–14.
Manighetti, I., M. Campillo, S. Bouley, and F. Cotton (2007). Earthquake scaling, fault segmentation, and structural maturity, Earth Planet. Sci. Lett. 253, 429–438.
Somerville, P. G. (2003). Magnitude scaling of the near fault rupture directivity pulse, Phys.Earth Planet. Interiors 137, 201–212.
Spudich, P., W. B. Joyner, A. G. Lindh, D. M. Boore, B. M. Margaris, and J. B. Fletcher (1999). SEA99: a revised ground motion prediction relation for use in extensional tectonic regimes, Bull. Seism. Soc. Am. 89, 1156–1170.
Biais
Data and Analysis
(d) Intermediate faults
Average of residuals
Coalinga (34)
Northridge (82)
Earthquake
name
San Fernando
Oroville
Santa Barbara
Tabas
Coyote Lake
Imperial Valley
Mammoth Lake
Coalinga
Morgan Hill
Nahanni
North Palm
Spring
Chalfant Valley
Edgecumbe
Whittier Narrows
Loma Prieta
2. Comparision of fault maturity with other source parameters
(a) Immature faults, number stations > 10
Residual
Examine the influence of long-term fault properties on earthquakes ground motions:
Influence of the structural maturity of faults on ground motions.
Comparison with other sources parameters: style of faulting and blind versus surface
rupturing earthquakes.