Bard, Pierre-Yves

Site-Specific Psha: Combined Effects of Single Station Sigma, Host-To-Target Adjustments and Non-Linear Behavior.

Abstract eng:
Several recent dramatic events drew the attention on the need to carefully reassess the very rare, high-impact, seismic hazard for large urban centers and critical facilities. Following this aim, the present trend all over the world is to more and more rely on probabilistic approaches to estimate seismic hazard, and determine annual exceedance probabilities for various ground-motion levels (down to very low probability levels). Most developments regarding the probabilistic seismic hazard assessment ("PSHA") methods have been concentrated on rock sites, although many cities are located on soft soil sites, which can significantly affect the shaking. In most PSHA studies, the amplification of the soil at the site is taken into account in a crude way, where hazard estimates can be both under-estimated (e.g. resonance effects are ignored) or overestimated (nonlinear effects are ignored). Critical facilities designed neglecting local site effects within the framework of PSHA may thus have unknown safety margins, with the possibility of under-design. This work contributes to provide recommendations for the incorporation of site response in PSHA estimates. We present a methodology on how to account for site-specific characterization, single station sigma, host-to-target adjustments and non-linear behavior of a soil column. In this study, we estimate the soil hazard for a 5000 years return period at the middle of the EUROSEISTEST valley, using different methods to account for site effects. We perform single station sigma hazard calculations, we apply host to target adjustments when required, we implement 1D linear and non-linear ground motion wave propagation, to finally describe the epistemic uncertainties related to the selected site-specific approach, and its impact on a probabilistic seismic hazard estimates.

Contributors:

Aristizábal, Claudia

Conference Title:

Proceedings of the 16th World Conference on Earthquake Engineering

Conference Title:

16th World Conference on Earthquake Engineering

Conference Venue:

Santiago (CL)

Conference Dates:

2017-01-09 / 2017-01-13

Rights:

Text je chráněný podle autorského zákona č. 121/2000 Sb.