Impact of Rupture Geometry Uncertainty on Rapid Earthquake Impact Assessment: A Case study

After a devastating earthquake, especially during the blind hours, compiling the geometry of the seismic rupture is challenging due to difficulties in constraining its geometry. However, this is a key component to initiate rapid earthquake impact assessment. Modeling seismic ruptures as a point-source approximation is often performed in the minutes or hours after the event, but it introduces errors and bias in the loss estimation due to the rough estimate of the site-to-source distances for all the elements exposed to the ground shaking. In this study, the effects of different rupture modeling approaches on ground shaking intensity measurement and impact estimates (economic loss, fatality and number of completely damaged buildings) are investigated for the Mw 7.7 Kahramanmaraş earthquake scenario that affected southern Turkey on February 6, 2023. The rupture modeling approaches followed in this study, corresponding to different uncertainty levels, include the point source approach (a), planar rupture (b), rupture based on an existing hazard model for Türkiye (c), and a complex finite rupture (d). The complex finite rupture results are used here as the benchmark losses. This study serves to quantitatively evaluate the error rate range corresponding to different rupture models and to understand the effectiveness of the proposed rupture modeling approach (c), which can lead to an increase in the accuracy and reliability of rapid impact estimates.