Probabilistic seismic hazard analysis

There are two different methods for quantifying the seismic hazard - based on deterministic approach and probabilistic approach. The deterministic seismic hazard analysis (DSHA) does not consider the uncertainties involved in the earthquake occm-rence process like the recurrence rate, magnitude uncertainty, attenuation characteristics of seismic waves etc. and gives the worst scenario of ground acceleration. Probabilistic seismic hazard analysis (PSHA) incorporates the uncertainties involved in the earthquake occurrence process. Since the uncertainty in earthquake occurrence is fully accounted in this method, this method is being widely followed for the evaluation of seismic hazard. The PSHA method adopted in this study... 

Steidl, J. H. (2000). Site response in southern California for probabilistic seismic hazard analysis. 

In the past 20 to 30 years the use of probabilistic concepts has allowed uncertainties in the size, location and rate of recurrence of earthquakes and in the variation of ground motion characteristics with earthquake size and location to be explicitly considered in the evaluation of seismic hazards. Probabilistic seismic hazard analysis (PSHA) provides aframe-work in which these uncertainties can be identified, quantified, and combined in a rational mannerto provide amore complete picture of seismic hazard. The proper performance of a PSHA requires careful attention to the problems of source characterization and ground motion parameter prediction and to the mechanics of the probability computations. 

Budnitz, R. J., Apostolakis, G., Boore, D. M., Cluff, L. S., Coppersmith, K. J., Cornell, C. A., Morris, P. A. (1997). Recommendations for probabilistic seismic hazard analysis guidance on uncertainty and use of experts. U.S. Nuclear Regulatory Commission Report NUREG/ CR- 6372. 

Kijko, A., Graham, G. (1998). Parametric-historic procedure for probabilistic seismic hazard analysis. Part I Estimation of maximum regional magnitude Mmax. Pure and Applied Geophysics, 152,413-442. doi 10.1007/ S000240050161... 

Steidl, J. H. (2000). Site response in southern California for probabilistic seismic hazard analysis. Bulletin of the Seismological Society of America, 90, S149-S169. doi 10.1785/0120000504... 

Currently, the assessment of seismic capacity is being carried out to comply with the relevant IAEA recommendations. In addition, a probabilistic seismic hazard analysis is included in the Temelin PSA Project scope in order to address the contribution from earthquake induced accident sequences to the overall CDF of the plant. The seismic hazard curves for the Temelin site has been developed and seismic fragility analysis has been performed for the structures and components. Based on the preliminary results (annual frequency of O.lg PGA (SSE) earthquake is lE-6/year), it is expected that the contribution of seismic events and the consequential accident sequences to the overall CDF will be negligible (i.e. less then 1% of overall CDF). The independent review of this PSA task is to be carried out in the framework of the 2nd IAEA IPERS (Level 1 - external initiating events) in August/September 1995. 

Site selection. In this phase only limited studies are performed (Probabilistic Seismic Hazard Analysis [PSHA], geohazards studies, etc.). They are based on existing data. The main references to define the seismic characteristics of the site are DS433 and SSG-9. 

U.S. NRC, United States Nuclear Regulatory Commission, 1997. Recommendations for Probabilistic Seismic Hazard Analysis Guidance on Uncertainty and Use of Experts. CR-6372 UCRL-ID-122160, Vols. 1 and 2. 

The lognormal is ubiquitous in probabilistic seismic hazard analysis (PSHA) and probabilistic seismic risk analysis (PSRA). To understand it, consider first the normal (not the lognormal) distribution. If a quantity X is normally distributed with mean fi and standard deviation scalar value in -00 < X < 00. Its cumulative distribution function (CDF) can be expressed as follows ... 

Seismic hazard is quantified many ways. One is through a hazard curve, commonly depicted on an x-y chart where the x-axis measures shaking intensity at a site and the y-axis measures either exceedance probability in a specified period of time or exceedance rate in events per unit time. See Fig. 3 for an example Cornell (1968) applied the theorem of total probability to create a hazard curve. What follows here is a summary of current procedures to perform probabilistic seismic hazard analysis (PSHA), but is conceptually identical to Cornell s work. 

McGuire RK (1995) Probabilistic seismic hazard analysis and design earthquakes closing the loop. Bull Seismol Soc Am 85(5) 1275-1284... 

Probabilistic seismic hazard analysis (PSHA) aims at estimating the probability that grotmd... 

McGuire RK, Arabasz WJ (1990) An introduction to probabilistic seismic hazard analysis. In Ward SH (ed) Geotechnical and environmental geophysics, vol 1. Society of Exploration Geophysics, Tulsa,... 

Seismic hazard analysis can be performed using two approaches, namely, deterministic seismic hazard analysis (DSHA) and probabilistic seismic hazard analysis (PSHA). Both use similar information to determine the design earthquake, while other hazard levels can also be established. Basic elements of deterministic analysis are also included in the probabilistic approach. The main difference is that the probabilistic approach takes into account the uncertainties and the likelihood of an actual earthquake exceeding the design ground motion. Examples of the outcome of the two approaches are as follows (FEMA-451B 2003) ... 

Probabilistic seismic hazard analysis The earthquake hazard for the examined site is a peak ground acceleration (PGA) of 0.50 g with a 2 % probability of being exceeded in a 50-year period. ... 

Probabilistic seismic hazard analysis (PSHA) was introduced by Cornell (1968). In contrast to DSHA, it assumes many scenarios, in which it... 

Kiinitzsky EL (1995) Deterministic versus probabilistic seismic hazard analysis for critical structures. Eng Geol 40 1-7... 

The strong-motion databases are also employed to select records that match a target spectrum and that can represent a response spectrum for a scenario event computed from a ground motion prediction equation or which may be derived from probabilistic seismic hazard analysis and presented as a uniform hazard spectrum (UHS) or which may be developed from building code provisions. The selected records, conveniently scaled to fit the target spectrum, are then used as input into numerical simulations for structural analysis and response site study. Several methods... 

Deterministic seismic hazard analysis Earthquake geology Earthquake hazard analysis Paleoseismology Probabilistic seismic hazard analysis Seismic hazard analysis Seismic hazard assessment... 

Importance of paleoseismic data in seismic hazard assessment has been recognized since the late 1970s. There are well-established methodologies developed for integrating the paleoseismic data in probabilistic seismic hazard analysis, which usually involve extending the earthquake catalog... 

Main IG (1995) Earthquakes as critical phenomena implications for probabilistic seismic hazard analysis. Bull Seismol Soc Am 85(5) 1299-1308... 

There is an ample spectrum of physics-based simulations available in the literature. Most of them have been published over the last two decades after supercomputing centers open for pubUc research became available in the mid- to late 1990s and early 2000s, which boosted the capacity of modelers to cmiduct regional-scale simulations at resolutions not possible before parallel computer codes were developed and tested. Some of these simulations have already been cited to ihus-trate the various aspects involved in physics-based simulation. However, they cannot all possibly be covered here, thus only a small selection is addressed next. The selection includes examples of scenario and real earthquake simulations that have been used in verification and validation studies those are the simulations of the Great Southern California ShakeOut and the 2008 Chino Hills, California, earthquake. Also covered here to a lesser extent is the application of physics-based simulation as a tool to construct a physics-based framework for probabilistic seismic hazard analysis, as it is done in the CyberShake project of the Southern California Earthquake Center. 

The SCEC CyberShake project is an effort to develop a framework for probabilistic seismic hazard analysis that incorporates explicitly the... 

Probabilistic Seismic Hazard Analysis History, Method, and Outputs... 

Progression from Deterministic to Probabilistic Seismic Hazard Analysis... 

Fig.1 The four steps of probabilistic seismic hazard analysis (After Cornell 1968)...

Critique on seismic hazard analysis Limitations on seismic hazard analysis Preference of DSHA over PSHA Problems with probabilistic seismic hazard analysis... 

Kliigel J-U (2007) Error inflation in probabilistic seismic hazard analysis. Eng Geol 90 18 192 Kossobokov V, Nekrasova A (2012) Global seismic hazard assessment program maps are erroneous. Seism Jnstrum 48 162—170... 

---