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The earthquakes that struck eastern Türkiye and Syria on 6 February 2023 force us to evaluate the models of seismic hazard and risk developed at the European scale for the region, specifically the 2020 European Seismic Hazard Model (ESHM20, Danciu et al.. 2021) and European Seismic Risk Model (ESRM20, Crowley et al.. 2021).We first verified that the ruptures associated to the two main earthquakes are present within the inventory of ruptures within the source model (the earthquake rupture forecasts or ERFs) for the East Anatolian Fault (first event) and Sürgü-Cardak Fault (second event. Ruptures close in magnitude and dimension to those observed were present in the ESHM20 ERFs.Preliminary ground motion observations were found to be consistent in their prediction of the expected shaking and its attenuation. Recorded near-fault ground motions also suggest strong pulse-like behaviour, indicating the need for such phenomena to be better captured in the GMMs.We have finally run scenario risk calculations using the ESRSM20 site, exposure and vulnerability models for the two main earthquakes. Expected fatalities were lower than those reported at the time of writing; however, many factors contribute to this. Further analysis is on-going to understand the difference, but critical areas for future improvement to the risk models should include state-dependent fragility, modelling of further epistemic uncertainty in exposure and vulnerability, and inclusion of spatial- and temporal correlations in ground motions across a region.List of ESHM20 and ESRM20 core team members (all co-authors of this abstract) on www.efehr.com, The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

To design user-centred and scientifically high-quality outreach products to inform about earthquake-related hazards and the associated risk, a close collaboration between the model developers and communication experts is needed. In this contribution, we present the communication strategy developed to support the public release of the first openly available European Seismic Risk Model and the updated European Seismic Hazard Model. The backbone of the strategy was the communication concept in which the overall vision, communication principles, target audiences (including personas), key messages, and products were defined. To fulfil the end-users’ needs, we conducted two user testing surveys; one for the interactive risk map viewer and one for the risk poster with a special emphasis on the European earthquake risk map. To further ensure that the outreach products are not only understandable and attractive for different target groups but also adequate from a scientific point of view, a two-fold feedback mechanism involving experts in the field was implemented. Through a close collaboration with a network of communication specialists from other institutions supporting the release, additional feedback and exchange of knowledge was enabled. Our insights, gained as part of the release process, can support others in developing user-centred products reviewed by experts in the field to inform about hazard and risk models.

When new seismic hazard models are published it is natural to compare them to existing models for the same location. This type of comparison routinely indicates differences between the assessed hazards in the various models. The question that then arises is whether these differences are scientifically significant, given the large epistemic uncertainties inherent in all seismic hazard models, or practically important, given the use of hazard models as inputs to risk and engineering calculations. A difference that exceeds a given threshold could mean that building codes may need updating, risk models for insurance purposes may need to be revised, or emergency management procedures revisited. In the current literature there is little guidance on what constitutes a significant or important difference, which can lead to lengthy discussions amongst hazard analysts and end users. This study reviews proposals in the literature on this topic and examines how applicable these proposals are for several sites considering various seismic hazards models for each site, including the two European Seismic Hazard Models of 2013 and 2020. The implications of differences in hazard for risk and engineering purposes are also examined to understand how important such differences are for potential end users of seismic hazard models. Based on this, we discuss the relevance of such methods to determine the scientific significance and practical importance of differences between seismic hazard models and identify some open questions. Finally, we make some recommendations for the future.