| 10 Apr 2026
Operational damage misclassification in scenario-based ShakeMaps: evidence from station-updated ground-motion fields in a deep-basin urban environment
Abstract. Near-real-time ShakeMap-based damage assessments are widely used to support rapid post-earthquake decision-making. However, their operational reliability depends on how accurately ground-motion fields represent local site and basin effects. This study investigates the potential for operational damage misclassification arising from purely scenario-based ShakeMap representations in deep-basin urban environments.
The 30 October 2020 Samos earthquake was analysed for the Mansuroğlu Neighborhood (Bayraklı District, Izmir, Türkiye) using a two-stage framework: (i) a scenario-based rapid damage estimation and (ii) a station-updated near-real-time configuration incorporating strong-motion recordings from Disaster and Emergency Management Authority of Türkiye (AFAD) stations located within a 3 km radius.
Results show that the scenario-based configuration systematically underestimates intermediate-period spectral demand (T = 0.6–1.0 s), which governs the response of the predominantly mid-rise reinforced concrete building stock. These discrepancies propagate into cumulative damage exceedance probability estimates. While the scenario-based approach largely confines the {Moderate + Extensive + Collapse} exceedance probability to the 0–10 % range, station-based updating increases this range to approximately 15–30 % in critical zones.
This shift represents a transition across an operationally meaningful threshold with direct implications for response categorization and resource prioritization during the early post-earthquake phase. The findings demonstrate that misclassification risk in rapid damage assessment arises not only from modelling uncertainty but also from threshold-sensitive distortions in exceedance estimation.
Even a limited number of spatially proximal strong-motion stations can substantially enhance the robustness of ground-motion representation. The study therefore highlights ShakeMap calibration as a governance-relevant intervention in seismic risk management rather than merely a technical refinement.
The Samos earthquake, which occurred offshore of Samos Island, Greece, on 30 October 2020 represents a key reference event for earthquake engineering studies in Türkiye, and merits the ground motion study undertaken by the author. The limitations of GMPEs are well-known, so the difference between scenario-based and observation-supported analyses will be large in deep-basin urban environments.
The author states that near-real-time ShakeMap-based damage assessments are widely used to support rapid post-earthquake decision
making. It is pointed out that in densely built urban districts such as Mansuroğlu, cumulative damage exceedance levels approaching 15–30% may increase the likelihood of localized road obstruction due to debris accumulation, thereby challenging uniform accessibility
assumptions embedded in emergency response planning. Under such conditions, the author states that response strategies may require area
specific prioritization.
Given the time elapsed of almost six years since the Samos earthquake, the author should address some key issues in post-earthquake decision making. In what specific ways can updated shaking maps improve post-earthquake response? How could updated shaking maps have contributed operationally to the rapid response on 30 October 2020, beyond immediate first-responder engagement?
Another key risk mitigation issue raised by this paper is the local level of code compliance. What data on code compliance is readily available to first responders?