Kernel Density Estimation Methods for a Geostatistical Approach in Seismic Risk Analysis: the Case Study of Potenza Hilltop Town (southern Italy) Maria Danese * , **, Maurizio Lazzari * , Beniamino Murgante ** International Conference on Computational Science and Its Applications (ICCSA 2008) - 30June -3July 2008 - Perugia, Italy * National Counsil of Research Archaeological and Monumental Heritage Institute, ** Università degli Studi della Basilicata, Dipartimento di Architettura, Pianificazione ed Infrastrutture di Trasporto
The problem: the seismic approach Program of prevision, prevention and protection Seismic event consequences evaluation and damages quantification Analysis of seismic damage scenarios
Analysis of seismic damage scenarios: instruments European Macroseismic Macroscale 1998 Vulnerability classes Damage levels Historical macroseismic scenarios Relationships between macroseismic intensity and damage levels
Analysis of seismic damage scenarios: limits <ul><li>Seismogeological effects </li></ul><ul><li>Mutual pounding of adjacent buildings </li></ul>Factors that needs a better evaluation “ The increase in shaking due to soil amplification or topographical conditions is part of the effects that intensity is a record of, and part of the hazard to which the built environment is exposed” * * Grünthal, G. G.: European Macroseismic Scale 1998. Conseil de l’Europe Cahiers du Centre Européen de Géodynamique et de Séisomologie, vol. 15 Luxembourg (1998) Importance of the spatial component in seismic damage scenarios
KDE: a method for the right choose of bandwidth Nearest-Neighbor Index Nearest-Neighbor Expected Distance NNI > 1 observed distance is higher than the expected distance; events are more scattered than expected. NNI < 1 observed distance is smaller than expected distance Nearest-Neighbor Observed Distance
The case of study: parameters selection <ul><li>Intensity choice </li></ul><ul><li>Building as autonomous scale (EMS98) </li></ul><ul><li>Relationship within buildings through reciprocal proximity and morphological factors </li></ul>
The case of study: parameters selection Intensity choice 6 5 D5 5 4 D4 3 3 D3 2 2 D2 1 1 D1 Intensity in northern sector Intensity in middle-southern sector Damage level
The case of study: parameters selection Kernel choice Cell size choice 0.1m
The case of study: parameters selection Bandwidth choice 6.8 Nearest neighbour mean calculated for whole point pattern Fixed for whole point pattern 1 KD map t (m) Methods used to estimate t Bandwidth approach Case
The case of study: parameters selection Bandwidth choice Sum of two resultant raster 3.9 6.8 D1-2-3 damage level: average of building’s minimum semi-dimension. D4-5 damage level: nearest neighbour mean calculated for whole point pattern. Two different fixed bandwidths 2 KD map t (m) Methods used to estimate t Bandwidth approach Case
The case of study: parameters selection Bandwidth choice Sum of two resultant raster 1.4÷9.9 6.8 4.1 D1-2-3 damage level: building’s minimum semi- Dimension D4-5 damage level: Building’s area ≤ mean + sd nearest neighbour mean calculated for whole point pattern Building’s area > mean + sd nearest neighbour mean calculated for whole point pattern multiplied by correction. One KDE with Fixed method, one with Adaptive method 3 KD map t (m) Methods used to estimate t Bandwidth approach Case
Conclusions and future developments <ul><li>The use of geostatistics to process historical macro-seismic data is a new field of application of these techniques and represents a new approach to territorial analysis. </li></ul><ul><li>Developments of the spatial analysis </li></ul><ul><ul><li>Considering more parameters that can influence the result </li></ul></ul><ul><li>Fields of application </li></ul><ul><ul><li>Possibility to define urban areas historically most exposed to seismic risk, achieving useful knowledge bases for emergency planning in case of earthquakes. This work could be also a good basis for Civil Defence Plan re-examination concerning the definition of waiting and refuge areas and strategic points of entrance to old town centre. </li></ul></ul><ul><ul><li>Possibility to define monumental heritage and strategic buildings that could be most exposed to seismic risk </li></ul></ul>
A particular slide catching your eye?
Clipping is a handy way to collect important slides you want to go back to later.