ML032730610
| ML032730610 | |
| Person / Time | |
|---|---|
| Site: | Clinton, 05200007, PROJ0718  |
| Issue date: | 09/25/2003 |
| From: | Exelon Generation Co, Exelon Nuclear |
| To: | Office of New Reactors |
| Shared Package | |
| ML032721596 | List:
|
| References | |
| +ReviewedClintonESP, +reviewednvg DEL-096-REV0 | |
| Download: ML032730610 (31) | |
Text
Modified from Obermeier (1996)
B-1-12 Seismic Hazards Report for the EGC ESP Site Flow Chart Showing Seismic and Nonseismic Mechanisms That Create Deformation Features in Sediment s:\\7900\\7935\\7935.000\\03_0303_sectb1\\_fig_b1-12.ai (2003-05-29, 11:07)
Figure
Dike intrudes
~8 feet of loess Dike approaches within 20 inches of ground surface Location of photograph A Note that:
- 1. Dike widens downward.
- 2. Gravelly sand fill fines upward.
- 3. Dike walls are sharp and irregular.
- 4. Dike is roughly tabular.
- 5. Dike occurs in clear association with source material.
- 6. Weathering within dike suggests it is relatively old.
A B
Bank rises approximately 12 feet above water level B-1-13 Seismic Hazards Report for the EGC ESP Site Photographs of Dike 1 at Locality SC 25 s:\\7900\\7935\\7935.000\\03_0303_sectb1\\_fig_b1-13(09,10).ai (2003-05-29, 11:09)
Figure
Detrital plant material Krotovina Filled Krotovina Note that:
- 1. Dike widens downward.
- 2. Sand in filling fines upwards.
- 3. Contacts are sharp and irregular.
- 4. Dike occurs in clear association with source material.
- 5. Dike includes clasts of silty clay, apparently ripped from its walls.
- 6. Maximum dike width is 1.5 in.
B-1-14 Seismic Hazards Report for the EGC ESP Site Photograph of Dike 2 at Locality SC 19 s:\\7900\\7935\\7935.000\\03_0303_sectb1\\_fig_b1-14(07).ai (2003-05-29, 11:10)
Figure
Upward extension of Dike 1 is truncated by the cross-bedded overlying sand unit Vertical portion of Dike 1 passes to the left of knife Gravel lag Cross-bedded, dense, fine sand Fluvial silt, sand and gravel Hard clayey till Cross-bedded, dense, fine sand Covered Covered Dike 1 Note: Knife is 8 in. long A.
B.
B-1-15 Seismic Hazards Report for the EGC ESP Site Photographs of Parts of Dike 1 at Locality M 6 s:\\7900\\7935\\7935.000\\03_0303_sectb1\\_fig_b1-15(13,12).ai (2003-05-29, 11:12)
Figure
Artificial fill Cross-bedded sand and gravel indicates fluvial deposition No liquefaction features were observed in this ~4 ft thick silt layer that overlies thick sequence of fluvial sand and gravel.
B-1-16 Seismic Hazards Report for the EGC ESP Site Photograph of Thick Silt Layer Overlaying Fluvial Deposit at Locality S14 s:\\7900\\7935\\7935.000\\03_0303_sectb1\\_fig_b1-16(14).ai (2003-05-29, 11:14)
Figure
Exhibit 1 to Attachment 1 to the Seismic Hazards Report for the Exelon Generation Company, LLC Early Site Permit Site Safety Analysis Report Appendix B
DEL-096-REV0 B1-E-1 EXHIBIT 1 Radiocarbon Dating
ATTACHMENT 1 TO APPENDIX B - SEISMIC HAZARDS REPORT FOR THE EGC EARLY SITE PERMIT SSAR FOR THE EGC EARLY SITE PERMIT B2-E-2 DEL-096-REV0
SSAR FOR THE EGC EARLY SITE PERMIT ATTACHMENT 1 TO APPENDIX B - SEISMIC HAZARDS REPORT FOR THE EGC EARLY SITE PERMIT DEL-096-REV0 B2-E-3
ATTACHMENT 1 TO APPENDIX B - SEISMIC HAZARDS REPORT FOR THE EGC EARLY SITE PERMIT SSAR FOR THE EGC EARLY SITE PERMIT B2-E-4 DEL-096-REV0
SSAR FOR THE EGC EARLY SITE PERMIT ATTACHMENT 1 TO APPENDIX B - SEISMIC HAZARDS REPORT FOR THE EGC EARLY SITE PERMIT DEL-096-REV0 B2-E-5
ATTACHMENT 1 TO APPENDIX B - SEISMIC HAZARDS REPORT FOR THE EGC EARLY SITE PERMIT SSAR FOR THE EGC EARLY SITE PERMIT B2-E-6 DEL-096-REV0
to the Seismic Hazards Report for the Exelon Generation Company, LLC Early Site Permit Site Safety Analysis Report Appendix B
DEL-096-REV0 B2-1-i Contents
- 1. Recurrence for New Madrid Characteristic Earthquakes............................................B2-1-1 1.1 Estimation of the Time Interval between Prehistoric New Madrid Earthquakes.................................................................................................................B2-1-1 2.1 Estimation of Recurrence Model Parameters.........................................................B2-1-2 2.1.1 Time-Independent (Poisson) Recurrence...................................................B2-1-3 2.1.2 Time-Dependent Recurrence.......................................................................B2-1-4
- 2. References............................................................................................................................B2-2-1
ATTACHMENT 2 TO APPENDIX B - SEISMIC HAZARDS REPORT FOR THE EGC EARLY SITE PERMIT SSAR FOR THE EGC EARLY SITE PERMIT DEL-096-REV0 B2-ii Tables B-2-1 Age Constraints Used for Assessment of Recurrence of New Madrid Characteristic Earthquakes.....................................................................................B2.T-1 B-2-2 Discrete Distributions for Rate of Characteristic New Madrid Earthquakes....... B2.T-3
SSAR FOR THE EGC EARLY SITE PERMIT ATTACHMENT 2 TO APPENDIX B - SEISMIC HAZARDS REPORT FOR THE EGC EARLY SITE PERMIT DEL-096-REV0 B2-1-iii Figures B-2-1 Illustration of Simulation Process for Evaluating Time Intervals Between Characteristic New Madrid Earthquakes B-2-2 Mean Repeat Time for New Madrid Characteristic Earthquakes
DEL-096-REV0 B2-1-1 CHAPTER 1 Recurrence for New Madrid Characteristic Earthquakes This attachment to Appendix B of the Site Safety Analysis Report (SSAR) for the Exelon Generating Company (EGC) Early Site Permit (ESP) Site presents an assessment of the recurrence of characteristic earthquakes on the central faults of the New Madrid seismic zone (NMSZ). Section 2.1.5.2.1 of Appendix B describes the paleoliquefaction investigations that have been conducted in the NMSZ region. These investigations have identified a number of paleoliquefaction features interpreted to have been caused by earthquakes and that have provided estimated age dates for these features. Table 2.1-5 of Appendix B summarizes the age dates for samples taken from these features, including the 95-percent confidence interval on the corrected calendar year for each sample. Various assessments of the paleoliquefaction features have interpreted them to be due to recurrence of characteristic earthquakes on the central faults of the NMSZ. The characteristic earthquake interpretation has been used for the EGC ESP analysis discussed in this Attachment. The first step in the recurrence assessment is to use these age dates and their uncertainties to provide constraints on the dates for prehistoric earthquakes. The intervals between these estimated dates then provide a sample of the repeat times between assumed characteristic earthquakes on the central New Madrid faults. The second step is to use these repeat times to estimate the parameters of appropriate recurrence models for the earthquakes. For this assessment, the uncertainties in the estimated dates were propagated through the estimation process using Monte Carlo simulation.
1.1 Estimation of the Time Interval between Prehistoric New Madrid Earthquakes The process used to estimate the time interval between prehistoric New Madrid liquefaction events is illustrated on Figure B-2-1. Part (a) shows an example data set of dates and their 95-percent confidence intervals for samples taken from individual paleoliquefaction features. The various symbols indicate whether the feature is identified to have formed before or after event Y (the earthquake of ~ AD 1450) or event X (the earthquake of ~ AD 900). The first step was to simulate a set of possible dates for each sample using the defined uncertainty limits. A normal distribution for the sample date was for the date estimation error assumed, and the 95-pecent confidence interval was used to define the +/-2 range for the age. Part (b) of Figure B-2-1 shows such a simulation using the data set from part (a).
The possible set of dates for individual samples in part (b) can now be used to constrain the possible ages for the prehistoric earthquakes. The oldest post-liquefaction date and the youngest pre-liquefaction date define the range of possible dates for each paleoearthquake.
For example, the solid circles shown in part (b) of Figure B-2-1 indicate samples taken from features that postdate event Y. The oldest of these is considered to provide an estimate of
ATTACHMENT 2 TO APPENDIX B - SEISMIC HAZARDS REPORT FOR THE EGC EARLY SITE PERMIT SSAR FOR THE EGC EARLY SITE PERMIT B2-1-2 DEL-096-REV0 the youngest date for event Y. The solid squares shown in part (b) of Figure B-2-1 indicate samples taken from features that predate event Y and the youngest of these provides an estimate of the oldest date for event Y. These two sample dates thus provide a date range for event Y, shown by dashed lines. A similar assessment provides an estimated data range for event X.
The actual dates for the individual events were then simulated from these date ranges. The true date was assumed to be uniformly distributed within the possible date range. The uniform distribution represents the maximum uncertainty distribution for a parameter when all that is known is the range of possible values. Part (c) of Figure B-2-1 shows an example simulation result for the dates of the prehistoric earthquakes. The simulated dates for the prehistoric events, along with the 1811 to 1812 earthquake sequence date, define a sample of the time interval between characteristic earthquakes that can be used to estimate the parameters of a recurrence model. This estimation can include the open interval from 1811-1812 to the present.
The uncertainty in estimated time intervals between prehistoric earthquakes was captured through Monte Carlo simulation. One hundred sets of sample ages (part b of Figure B-2-1) were simulated. For each set of simulated sample ages, 100 simulations of prehistoric earthquake dates were created. The resulting 10,000 samples of time intervals between characteristic earthquakes were then used to develop 10,000 estimates of recurrence parameters as described in Section 1.2 of this attachment. The simulations were performed using data from the northeastern portion of the NMSZ where at least three prehistoric earthquake sequences were identified, events Y and X described above and an earlier event W (~ AD 300) (see Figure 2.1-26 of Appendix B). The individual samples used in the analysis are given in Table B-2-1. The statistics of the simulated ages for the prehistoric earthquakes are summarized in the following table.
Statistics of Estimated Dates for Prehistoric NMSZ Characteristic Earthquakes Event Event Date Y
1454 AD+/- 55 years X
917 AD +/- 28 years W
325 AD +/- 252 years 1.2 Estimation of Recurrence Model Parameters Two general types of recurrence models have been used to characterize the occurrence of characteristic earthquakes, time-independent and time-dependent. The time independent or Poisson model is the recurrence model commonly use in probabilistic seismic hazard analysis (PSHA) formulations for earthquakes of all sizes and was the recurrence model used in the Electric Power Research Institute Seismic Owner Group (EPRI-SOG) characterization of earthquake recurrence for all sources. The implication of this model is that the time interval between events is exponentially distributed (with the mode at zero),
and a coefficient of variation of the time intervals is equal to 1.0. The likelihood of
SSAR FOR THE EGC EARLY SITE PERMIT ATTACHMENT 2 TO APPENDIX B - SEISMIC HAZARDS REPORT FOR THE EGC EARLY SITE PERMIT DEL-096-REV0 B2-1-3 occurrence of an earthquake in any time interval is independent of when the previous event occurred. However, the physics of the process of stress accumulation followed by release in characteristic earthquake ruptures on faults has led a number of investigators to consider time-dependent recurrence models for these sources. In the simplest form, time-dependent recurrence models are cast as a renewal model in which the likelihood of the next characteristic event occurring in a specified time interval is dependent only on the elapsed time since the previous characteristic event (e.g., Cornell and Winterstein, 1988; Wu et al.,
1995). These models typically use a skewed distribution, such as the lognormal, Weibull, or gamma, to represent the distribution of times between characteristic earthquakes. Recently the Working Group on California Earthquake Probabilities (Working Group, 2003) has used these types of models to characterize the likelihood of large earthquakes on faults in the San Francisco Bay area. Cramer (2001) used a lognormal distribution to estimate the average repeat time for large earthquake in the NMSZ based on the estimated earthquake dates presented in Tuttle and Schweig (2000). In the following, recurrence model parameters are estimated for characteristic New Madrid earthquakes using both time independent and time-dependent recurrence models.
1.2.1 Time-Independent (Poisson) Recurrence For the time-independent or Poisson recurrence model, the time interval between earthquakes, t, is exponential distributed with probability density given by:
t e
t f
=
)
(
(Eq. B-2-1) and cumulative probability given by t
e t
F
=1
)
(
(Eq. B-2-2) where is the average rate of characteristic events (1/ is the average time between events).
Given a sample of n time intervals and one open interval, t0, the likelihood function for the observed data set is given by:
{
})
(
1
)
(
)
(
0 1
t F
t f
L n
i i
=
=
(Eq. B-2-3)
The maximum likelihood solution for the mean rate is given by the expression:
0 1
likelihood maximum t
t n
n i
i +
=
=
(Eq. B-2-4)
An empirical uncertainty distribution for the parameter can be determined by computing the likelihood of observing the sample of event inter-arrival times (ti..tn and t0) for a range values of, and then normalizing these likelihoods to form a discrete probability distribution. This process was used to develop a probability distribution for for each set of simulated prehistoric earthquake dates. The resulting 10,000 likelihood distributions were then averaged to produce a composite uncertainty distribution for. Figure B-2-2 shows the resulting cumulative distribution for the average time between events, 1/, estimated from
ATTACHMENT 2 TO APPENDIX B - SEISMIC HAZARDS REPORT FOR THE EGC EARLY SITE PERMIT SSAR FOR THE EGC EARLY SITE PERMIT B2-1-4 DEL-096-REV0 the simulation of times for events W, X, and Y, and the open interval post 1811-1812. This distribution was represented in the hazard analysis by a five-point discrete approximation to a continuous distribution defined by Miller and Rice (1983). This discrete distribution is listed in Table B-2-2.
1.2.2 Time-Dependent Recurrence For the time-dependent renewal recurrence model, there are a variety of distributions that have been used to model the variability in the time between events, such as the lognornmal, Weibull, and gamma distributions. Recently, Matthews et al. (2002) have proposed a model based on the inverse Gaussian distribution for inter-arrival times of repeated large ruptures on a fault. This model, termed the Brownian Passage Time (BPT) model was used by the Working Group (2003) to assess the probabilities of large earthquakes in the San Francisco Bay area. The examples given in Matthews et al. (2002) show that the BPT and lognormal distributions produced very similar estimates of hazard for elapsed times less that the average time between events. The lognormal model was used in this analysis because of its simpler form and the fact that the elapsed time since the 1811-1812 sequence is less than the expected repeat time for large New Madrid earthquakes.
For the lognormal model, the time interval between earthquakes, t, is distributed with probability density given by:
t t
t e
t t
t f
t
µ
=
ln 2
2 ln 2
2
)
(ln exp
)
(
2 ln (Eq. B-2-5) and cumulative probability given by
=
t dt t
f t
F
)
(
)
(
(Eq. B-2-6) where µlnt and lnt are the mean log inter-arrival time and its standard deviation, respectively. The mean inter-arrival time, t is given be the expression:
(
)
2
/
exp 2
ln 2
ln t t
t
µ
+
=
(Eq. B-2-7)
Given a sample of n time intervals and one open interval, t0, the likelihood function for the observed data set is again given by equation (B-2-3) with f(t) and F(t) replaced by equations (B-2-5) and (B-2-6). The maximum likelihood solution must be found by numerical methods. Because of the very limited data set, the estimate of the standard deviation is highly uncertain. Therefore, the standard deviation has been constrained for the assessment described in this Attachment to values reported from examination of larger data sets. Based on examination of a number of data sets, the Working Group (2003) developed an uncertainty distribution for the coefficient of variation of for the BTP model consisting of three weighted values of 0.3 (0.2), 0.5 (0.5), and 0.7 (0.3). (The standard deviation of ln(t) is approximately equal to the coefficient of variation for lnt<1.) The Working Group (2003) weighted distribution was adopted to constrain the standard deviation of lnt.
SSAR FOR THE EGC EARLY SITE PERMIT ATTACHMENT 2 TO APPENDIX B - SEISMIC HAZARDS REPORT FOR THE EGC EARLY SITE PERMIT DEL-096-REV0 B2-1-5 The process described in Section 1.2.1 of this Attachment was repeated to develop an empirical distribution for µlnt, given a specified value of lnt. Dates were simulated for events X and Y. Event W was not used in estimating the parameters for the renewal process because of the limited information to constrain its timing. For each simulated set of dates for the prehistoric New Madrid earthquakes, equations (B-2-3), (B-2-5), and (B-2-6) were used to compute the likelihood of observing the sample for a range of values of µlnt. These likelihoods were normalized to define a discrete distribution for µlnt. The estimation process was repeated for each of the 10,000 simulated sets of dates and the resulting distributions averaged to produce a composite distribution for µlnt. These distributions are plotted on Figure B-2-2 where equation (B-2-7) has been used to convert µlnt into t, the average time between events, for comparison with the Poisson values of 1/. These distributions were represented in the hazard analysis by the five-point discrete approximations to a continuous distribution listed in Table B-2-2.
For the renewal recurrence model, the probability of an earthquake in the next time interval t is given be the expression:
)
(
1
)
(
)
(
)
to in time event
(
0 0
0 0
0 t
F t
F t
t F
t t
t Prenewal
+
=
+
(Eq. B-2-8)
The basic PSHA formulation used to assess the site hazard assumes that the occurrence of individual earthquakes conforms to a Poisson process. In order to combine the hazard from earthquakes defined by a renewal process into the total hazard, an equivalent Poisson rate is defined such that a Poisson process will given a probability of at least one earthquake in time interval t is that is equal to the probability given by equation (B-2-8). The equivalent Poisson rate, renewal, is given by the expression:
[
]
t t
t t
Prenewal renewal
+
=
/
)
to in time event
(
1 ln 0
0
(Eq. B-2-9)
A time period of 50 years was chosen as the time period of interest for the ESP application.
The corresponding estimates of renewal are listed in Table B-2-2.
The last column of Table B-2-2 lists the average equivalent repeat time for characteristic earthquakes derived from the discrete distributions for or renewal. The values in bold are the inverse of the weighted average event frequency for each model. Assigning equal weight to the Poisson and renewal models, the resulting weighted average frequency of characteristic events is 1/465 events per year.
DEL-096-REV0 B2-2-1 CHAPTER 2 References Cornell, C.A., and S.R. Winterstein. Temporal and Magnitude Dependence in Earthquake Recurrence Models. Bulletin of the Seismological Society of America. Vol. 78, No. 4. pp. 1522-1537. 1988.
Cramer, C.H. A Seismic Hazard Uncertainty Analysis for the New Madrid Seismic Zone.
Engineering Geology. Vol. 62. pp. 251-266. 2001.
Kelson, K.I., R.B. Van Arsdale, G.D. Simpson, and W.R. Lettis. Assessment of the Style and Timing of Surficial Deformation along the Central Reelfoot Scarp, Lake County, Tennessee.
Seismological Research Letters. Vol. 63, No. 3. pp. 349-356. 1992.
Kelson, K.I., G.D. Simpson, R.B. Van Arsdale, C.C. Haraden, and W.R. Lettis. Multiple Late Holocene Earthquakes along the Reelfoot Fault, Central New Madrid Seismic Zone. Journal of Geophysical Research. Vol. 101, No. B3. pp. 6151-6170. 1996.
Li, Y., E.S. Schweig, M.P. Tuttle, and M.A. Ellis. Evidence for Large Prehistoric Earthquakes in the Northern New Madrid Seismic Zone, Central United States. Seismological Research Letters. Vol. 69. pp. 270-276. 1998.
Matthews, M.V., W.L. Ellsworth, and P.A. Reasenberg. A Brownian Model for Recurrent Earthquakes. Bulletin of the Seismological Society of America. Vol. 92. No. 6. pp. 2233-2250.
2002.
Miller, A.C., and T.R. Rice. Discrete Approximations of Probability Distributions.
Management Science. Vol. 29, No. 3, pp. 352-362. 1983.
Tuttle, M.P. Late Holocene Earthquakes and their Implications for Earthquake Potential of the New Madrid Seismic Zone, Central United States. Ph.D. Dissertation. University of Maryland. 250 pp. 1999.
Tuttle, M.P. The Use of Liquefaction Features in Paleoseismology: Lessons Learned in the New Madrid Seismic Zone, Central United States. Journal of Seismology. Vol. 5. pp. 361-380.
2001.
Tuttle, Martitia P. M. Tuttle & Associates. Written (Electronic) Communication. February 27, 2003.
Tuttle, M.P., and E.S. Schweig. The Earthquake Potential of the New Madrid Seismic Zone. American Geophysical Union, EOS Transactions. Vol. 81, No. 19, p. S308. 2000.
Tuttle, M.P., and E.S. Schweig. Towards a Paleoearthquake Chronology for the New Madrid Seismic Zone. Collaborative Research, M. Tuttle & Associates and Eastern Region Hazards Team, U.S. Geological Survey. Annual Report Submitted to the U.S. Geological Survey.
USGS External Project No. 1434-99HQGR0022. 18 pp. 2001.
ATTACHMENT 2 TO APPENDIX B - SEISMIC HAZARDS REPORT FOR THE EGC EARLY SITE PERMIT SSAR FOR THE EGC EARLY SITE PERMIT B2-1-2 DEL-096-REV0 Tuttle, M.P., and L.W. Wolf. Towards a Paleoearthquake Chronology for the New Madrid Seismic Zone. Progress Report Submitted to the U.S. Geological Survey NEHRP. USGS External Project No. 1434-01HQGR0164. 36 pp. 2003.
Tuttle, M.P., J.D. Sims, K. Dyer-Williams, R.H. Lafferty III, and E.S. Schweig III. Dating of Liquefaction Features in the New Madrid Seismic Zone. U. S. Nuclear Regulatory Commission Report NUREG/GR-0018. 42 pp. (plus appendices). 2000.
Working Group on California Earthquake Probabilities (Working Group). Earthquake Probabilities in the San Francisco Bay Region: 2002-2031. U.S. Geological Survey Open-File Report 03-214. 2003.
Wu, S.-C., CA. Cornell, and S.R. Winterstein. A Hybrid Recurrence Model and Its Implication on Seismic Hazard Results. Bulletin of the Seismological Society of America. Vol.
85, No. 1. pp. 1-16. 1995.
DEL-096-REV0 B2.T-1 TABLE B-2-1 AGE CONSTRAINTS USED FOR ASSESSMENT OF RECURRENCE OF NEW MADRID CHARACTERISTIC EARTHQUAKES Seismic Hazards Report for the ECG ESP Site Name of Site Lab Sample Number1 Material Time Relationship of Sample to Liquefaction 14C Age, years BP +/- 1-sigma Calibrated Age 2-sigma (95% Probability)2 Age Estimate Based on Ceramics and Points Maximum Age Range (published correlation, comments)
Estimated Event Correlation Reference Beta-133006 (T2-C14)
Charcoal (top of lower sand blow)
Preliquefaction (event 2)
Postliquefaction (event 1) 240 +/- 50 AD 1520 to 1590 AD 1620 to 1690 AD 1740 to 1810 AD 1930 to 1950 NA Beta-133005 (T2-C13)
Charcoal (19 cm below sand blow)
Preliquefaction (event 1) 920 +/- 40 AD 1020 to 1210 NA Amanda Artifacts, including diagnostic ceramics Preliquefaction (event 1)
NA NA AD 800 to 1400 (Early and Middle Mississippian)
Event in trench T2, followed by event in trench T1, occurred during or soon after AD 1000 to 1400 (Middle Mississippian)
Two events:
1811-1812 and event Y, 1450 +/- 150 yr.
Tuttle et al.
(2000)
Burkett TR-6 Artifacts-Burkett phase Preliquefaction (event 3)
NA NA
~ 400 BC to AD 330 Early-Middle Woodland (radiocarbon dating of horizon by Prentice Thomas)
Event 3 probably occurred at end of Burkett phase (AD 300 +/- 200 yr.)
Event W AD 300 +/- 200 yr.
May be same event as older Towosaghy S1 event Tuttle and Schweig (2001)
Tuttle (M.
Tuttle and Associates, electronic commun. to Kathryn
- Hanson, February 27, 2003).
Beta-102500 Charcoal and ceramics Postliquefaction 1150 +/- 50 AD 780 to 1000 AD 400 to 1000 Late Woodland Hillhouse Beta-102499 Charcoal Preliquefaction 1140 +/- 50 AD 790 to 1010 NA AD 790 to 1000 Event X 900 +/- 100 yr.
Tuttle (1999)
Johnson 5 Beta-102505 Soil Preliquefaction 1110 +/- 80 AD 770 to 1040 AD 800 to 1000 Late Woodland-Early Mississippian AD 770 to 1670 Minimum age not well constrained; probably formed during Late Woodland-Early Mississippian. Soil development suggests sand blow formed prior to 1811 and was exposed at the surface for at least 670 years Event X 900 +/- 100 yr.
Tuttle (1999)
Beta-49608 Charcoal Post-monoclinal folding; colluvium AD 1430 to 1650 NA K1 Champey Pocket Beta-49609 Charcoal Pre-monoclinal folding AD 1220 to 1390 NA Event Y AD 1220 to 1650; ~AD 1400 Event Y (1450 +/- 150 yr.)
Kelson et al.
(1992 and 1996)
TABLE B-2-1 CONSTRAINTS USED FOR ASSESSMENT OF RECURRENCE OF NEW MADRID CHARACTERISTIC EARTHQUAKES Seismic Hazards Report for the ECG ESP Site DEL-096-REV0 B2.T-2 Name of Site Lab Sample Number1 Material Time Relationship of Sample to Liquefaction 14C Age, years BP +/- 1-sigma Calibrated Age 2-sigma (95% Probability)2 Age Estimate Based on Ceramics and Points Maximum Age Range (published correlation, comments)
Estimated Event Correlation Reference Beta-48553 Charcoal; artifacts Postliquefaction AD 430 to 890 AD 800 to 1000 Close minimum (third most recent event)
Event X AD 780 to 1000 Event X 900 +/- 100 yr.
CAMS-13559 Charcoal Pre-scarp formation and re-development of graben (event Y) 660 +/- 60 AD 1260 to 1410 NA Event post-dates AD 1260 Event Y (1450 +/- 150 yr.)
CAMS-13540 Charcoal Post-graben formation (event X) 960 +/- 60 AD 980 to 1220 NA Event X AD 780 to 1000; close minimum K2 Proctor City CAMS-13537 Charcoal Pre-graben formation (event X) 1110 +/- 60 AD 780 to 1030 NA Close maximum Event X 900 +/- 100 yr.
Kelson et al.
(1996)
L2 (Site WD)
Beta-71234 Soil (dispersed carbon)
Postliquefaction (event 1) 1140 +/- 60 AD 770 to 1040 NA Two sand blows, 1811-1812 and 900 +/- 100 yr.
Lower sand blow exposed at surface
~ 800 +/- 100 yr. prior to burial by younger sand blow 1811-1812 (event 2)
Event X 900 +/- 100 yr.
(event 1)
Li et al. (1998)
Beta-146738 Wood W2 collected from silt deposit above sand blow Postliquefaction 230 +/- 40 AD 1530 to 1550 AD 1640 to 1680 AD 1740 to 1810 AD 1930 to 1950 NA Obion 200 Beta-146737 Wood W1 collected within 1 cm of base of sand blow Preliquefaction 590 +/- 40 Close maximum AD 1300 to 1420 NA Before AD 1810 and After AD 1300 (based on probability distribution)
Event Y (1450 +/- 150 yr.)
Tuttle and Schweig (2001)
Beta-152008 Wood (W2 from outer 1 cm of horizontally bedded log buried by sand blow)
Preliquefaction 800 +/- 60 AD 1060 to 1080 AD 1150 to 1290 NA Obion 216 Beta-152009 Wood (W4 from outer 1 cm of tree trunk in growth position in clay deposit beneath sand blow.
Preliquefaction 730 +/- 60 AD 1160 to 1300 NA Event soon after AD 1300 (based on probability distribution)
Event Y (1450 +/- 150 yr.)
Tuttle and Schweig (2001); Tuttle and Wolf (2003)
Towosaghy (re-excavate S1 site)
Dating underway Artifacts Postliquefaction (event 1)
NA NA Late Woodland to Early Mississippian (AD 400 to 1000) above sand blow; few artifacts below sand blow Evidence for event 1 but not event 2 of Saucier May correlate to event W AD 300 +/- 200 yr.
(event 1)
Tuttle and Wolf (2003) 1 BetaBeta Analytic, Inc. (Miami, FL); CAMSCenter for Accelerator Mass Spectrometry (Livermore, CA) 2 Intervals that can be eliminated based on stratigraphic or historical evidence are shown in italics.
DEL-096-REV0 B2.T-3 TABLE B-2-2 DISCRETE DISTRIBUTIONS FOR RATE OF CHARACTERISTIC NEW MADRID EARTHQUAKES Seismic Hazards Report for the ECG ESP Site Recurrence Model 1/
(events/year) exp(µlnt)
(years)
Event Frequency or renewal (events/year)
Weight Equivalent Average Repeat Time (years) 186.6 0.005359 0.10108 187 294.1 0.003400 0.24429 294 442.5 0.002256 0.30926 443 704.2 0.001420 0.24429 704 1388.9 0.000720 0.10108 1,389 Poisson 401 294.3 0.004273 0.10108 234 365.3 0.001420 0.24429 704 435.7 0.000430 0.30926 2,323 515.4 0.000104 0.24429 9,638 644.9 0.000010 0.10108 101,591 Renewal (Lognormal lnt = 0.3) 1,066 233.3 0.006478 0.10108 154 334.5 0.003102 0.24429 322 446.2 0.001390 0.30926 720 590.6 0.000503 0.24429 1,988 846.7 0.000091 0.10108 10,988 Renewal (Lognormal lnt = 0.5) 506 189.5 0.006080 0.10108 164 313.7 0.003246 0.24429 308 464.5 0.001676 0.30926 597 693.1 0.000691 0.24429 1,447 1147.8 0.000155 0.10108 6,453 Renewal (Lognormal lnt = 0.7) 474
Figure B-2-1 Seismic Hazards Report for the EGC ESP Site Illustration of Simulation Process for Evaluating Time Intervals between Characteristic New Madrid Earthquakes Non-GDS
Figure B-2-2 Seismic Hazards Report for the EGC ESP Site Mean Repeat Time for New Madrid Characteristic Earthquakes Non-GDS