Sensitivity of Earthquake Damage Estimation to the Input Data (Soil Characterization Maps and Building Exposure): Case Study in the Luchon Valley, France

Abstract

This article studies the effects of the soil data and exposure data of residential building inventories, as well as their spatial resolution, on seismic damage and loss estimates for a given earthquake scenario. Our aim is to investigate how beneficial it would be to acquire higher resolution inventories at the cost of additional effort and resources. Seismic damage computations are used to evaluate the relative influence of varying spatial resolution on a given damage model, where other parameters were held constant. We use soil characterization maps and building exposure inventories, provided at different scales from different sources: the European database, a national dataset at the municipality scale, and local field investigations. Soil characteristics are used to evaluate site effects and to assign amplification factors to the strong motion applied to the exposed areas. Exposure datasets are used to assign vulnerability indices to sets of buildings, from which a damage distribution is produced (based on the applied seismic intensity). The different spatial resolutions are benchmarked in a case-study area which is subject to moderate-to-average seismicity levels (Luchon valley in the Pyrénées, France). It was found that the proportion of heavily damaged buildings is underestimated when using the European soil map and the European building database, while the more refined databases (national/regional vs. local maps) result in similar estimates for moderate earthquake scenarios. Finally, we highlight the importance of pooling open access data from different sources, but caution the challenges of combining different datasets, especially depending on the type of application that is pursued (e.g., for risk mitigation or rapid response tools).

Impact of exposure spatial resolution on seismic loss estimates in regional portfolios

“…For example, the gridded exposure can be improved by weighting site properties within each grid cell or considering variable grids denser around the main faults and where site properties tend to vary. In addition, while this work has focused on regional scale risk studies, further analysis should be undertaken at sub-regional and urban scale in order to understand where a suitable balance can be struck between exposure resolution, uncertainty characterization and computational cost, when more detailed information may be available (e.g., Fayjaloun et al 2021). Since the effects of data resolution depend strongly on the variation in the hazard (see the discussion), future studies should focus on mitigating the bias at the ground motion level.…”

The Impact of High-Energy Mining-Induced Tremor in a Fault Zone on Damage to Buildings

“…The large difference in horizontal ground vibration PGV Hmod values at the individual station is not explained by the values of vibration amplification coefficient W f at the point of registration. Bearing in mind that seismic waves propagation is affected by lithostratigraphic and topographic local conditions-e.g., [26][27][28][29][30][31][32][33][34], the distribution of the amplification factor W f is shown in Figure 5. The error in determining the value PGV H indicates that the standard deviation S = 0.314.…”

Reduction of Bias and Uncertainty in Regional Seismic Site Amplification Factors for Seismic Hazard and Risk Analysis

“…They concluded that amplification factors are best predicted as a function of V s30 in conjunction with the dominant period of the site and the shear wave velocity gradient. Fayjaloun et al [20] investigated the damage scenario of residential buildings shaken by moderate ground acceleration (200 cm 2 /s) with and without consideration for the site amplification factor of 1.5. It is noted from Régnier et al [21,22] that the EQL analysis should be considered reliable with reference to PGA lower than 0.2-0.3 g.…”