Investigating possible regional dependence in strong ground motions

John Douglas (1)

1 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)

It is common practice to use ground-motion models, often developed by regression on recorded accelerograms, to predict the expected earthquake ground motions at sites of interest. An important consideration when selecting these models is the possible dependence of ground motions on geographical region, i.e., are median ground motions in the (target) region of interest for a given magnitude and distance the same as those in the (host) region where a ground-motion model is from, and are the aleatory variabilities of ground motions also similar? In this brief article, some of the recent literature with relevance to these questions is summarized. It is concluded that although some regions seem to show considerable differences in shaking it is currently more defensible to use well-constrained models, possibly based on data from other regions, rather than use local, often poorly-constrained, models. In addition, it is noted that the presence of “pseudo-regional dependency” due to differences in, for example, focal depths, average shear-wave velocity profiles or focal mechanisms can lead to apparent variations between areas when these variations could be captured in well-characterized ground-motion prediction equations.

Mots clés: seismic hazard; ground-motion prediction equations; ground-motion models; regional dependency

Domaines: Géophysique [physics.geo-ph]; Géophysique [physics.geo-ph]; Milieux et Changements globaux

John Douglas. Investigating possible regional dependence in strong ground motions. Sinan Akkar, Polat Gülkan, Torild van Eck. Earthquake Data in Engineering Seismology, Springer Science+Business Media B.V., pp.29-38, 2011, Geotechnical, Geological, and Earthquake Engineering, ⟨10.1007/978-94-007-0152-6_3⟩. ⟨hal-00567198⟩