A hybrid model for mapping simplified seismic response via a GIS-metamodel approach

In earthquake-prone areas, site seismic response due to lithostratigraphic sequence plays a key role in seismic hazard assessment. A hybrid model, consisting of GIS and metamodel (model of model) procedures, was introduced aimed at estimating the 1-D spatial seismic site response in accordance with spatial variability of sediment parameters. Inputs and outputs are provided and processed by means of an appropriate GIS model, named GIS Cubic Model (GCM). This consists of a block-layered parametric structure aimed at resolving a predicted metamodel by means of pixel to pixel vertical computing. The metamodel, opportunely calibrated, is able to emulate the classic shape of the spectral acceleration response in relation to the main physical parameters that characterize the spectrum itself. Therefore, via the GCM structure and the metamodel, the hybrid model provides maps of normalized acceleration response spectra. The hybrid model was applied and tested on the built-up area of the San Giorgio del Sannio village, located in a high-risk seismic zone of southern Italy. Efficiency tests showed a good correspondence between the spectral values resulting from the proposed approach and the 1-D physical computational models. Supported by lithology and geophysical data and corresponding accurate interpretation regarding modelling, the hybrid model can be an efficient tool in assessing urban planning seismic hazard/risk. © Author(s) 2014

Multihazard susceptibility assessment: A case study – Municipality of Štrpce (Southern Serbia)

The municipality of Štrpce (Southern Serbia) is an area located within Šar Mountain National Park, which is of great ecological importance. Due to the vicinity of settlements, it is necessary to analyze the terrain's susceptibility to natural hazards. The main goal of this research was to determine locations that are highly vulnerable at times of natural hazards (such as earthquakes, erosion, torrential flooding, snow avalanches, and forest fires). The first step in this research was to analyze seismic hazards for a 475 years return period (VII–VIII MCS for the observed area), which was possible by means of Geographic Information Systems. The second step was to determine the intensity of erosion and total sediment production using the Erosion Potential Model. The third step was related to the analysis of the potential of torrential floods using the Flash Flood Potential Index. The Avalanches Potential Index method was used as the fourth step. The fifth step included the analysis of a terrain susceptibility to the occurrence of forest fires. Following the five criteria analysis, weight coefficients were assigned to each of the analyzed parameters by using the Analytical Hierarchy Process (AHP), which provided results of the total susceptibility to natural hazards of the territory of Štrpce. Results indicated that over 45% of the municipality is highly or very highly susceptible to various natural hazards. This article represents a significant step toward a better understanding of natural hazards and it provides a unique knowledge basis for establishing the management and mitigation guidelines and measures, not only within the researched area but at regional and national levels as well