Sensitivity of Parameters for Probabilistic Seismic Hazard Analysis Using a Logic Tree Approach

Abstract

The sensitivity of different parameters used in probabilistic seismic hazard calculation is investigated by different logic tree runs with alternative magnitude sets, source zone models and attenuation relations, and with different sets of values for the seismicity parameters and the σ-value. Also the influence from the different parameters on the hazard uncertainty, represented by fractiles, is investigated. The calculations are made for peak ground acceleration at a site near Aachen in the Lower Rhine Embayment. The model where the site is located in a larger source zone gives lower hazard values. This is typical for the case where the seismicity near the site is high relative to its surrounding. The hazard curves for the different attenuation functions are similar, an effect of the similarity of the functions themselves. However, a large sensitivity of this parameter is indicated for small mean return periods. An increased σ-value implies a moderate increase of the hazard at long mean return periods. The hazard is increasing for decreased focal depth, decreased ß-value and increased maximum expected magnitude, respectively. However, the effects are noteworthy only at low hazard levels for variations in the focal depth and to some extent in the maximum expected magnitude. Finally, decreasing the minimum magnitude thought to be of engineering relevance causes a drastic increase of the hazard at small mean return periods.

The probabilistic seismic hazard assessment of Germany—version 2016, considering the range of epistemic uncertainties and aleatory variability

“…A considerable number of methods are in use that attempt to extend the conceivable range of M max up to its possible upper range. We employ here, as in all our previous studies on PSHA in Europe north of the Mediterranean region since Grünthal and Wahlström (2001) and Grünthal (2000, 2001), a Bayesian approach based on the ergodic principle; i.e. the substitution of temporal limitations in the observational record using observations of the same phenomenon taken from a larger spatial domain.…”

“…those by Ahorner and Rosenhauer (1978) for SW Germany, who apply the generalized Gumbel distribution of magnitudes on the basis of Monte-Carlo simulations (Ahorner and Rosenhauer 1975), which was later updated with the focus on western Germany (Ahorner and Rosenhauer 1986) and modified for the Lower Rhine embayment (Rosenhauer and Ahorner 1994). For the latter area, Grünthal et al (2004Grünthal et al ( , 2006 calculated PSHA with an advanced consideration of uncertainties by applying logic trees and distributions of aleatory variability as our standard approach since Grünthal and Wahlström (2001) and Grünthal (2000, 2001).…”

Probabilistic Seismic Hazard Assessment (Horizontal PGA) for Fennoscandia Using the Logic Tree Approach for Regionalization and Nonregionalization Models

“…A general survey of the uncertainty of various input parameters and assumptions in seismic hazard calculation is provided by Bender and Perkins (1993). Grünthal and Wahlström (2001) investigated the sensitivity of individual input parameters.…”

“…According to Equation (1), this corresponds to M L (UPP) = 4.9. The minimum magnitude is the smallest magnitude contributing to the calculated seismic hazard, and the choice of this value has impact on the hazard at small mean return periods, i.e., the larger the minimum magnitude, the narrower the range of contributing magnitudes and thus the smaller the hazard (e.g., see Bender and Perkins, 1993;Grünthal and Wahlström, 2001).…”

Site-specific response spectra from the combination of microzonation with probabilistic seismic hazard assessment—An example for the Cologne (Germany) area

“…A formal method of handling this uncertainty is the logic tree approach [2][3][4]. Applications of the logic tree approach for the area of the present study were performed by Grünthal and Wahlström [5][6][7]. Another approach to treat uncertainties is the Monte Carlo technique (e.g.…”