Presentation by Dr. A. Magrin
Transcript
Presentation by Dr. A. Magrin
8 july 2013 - ERES 2013 Earthquake recurrence and seismic hazard assessment: a comparative analysis over the Italian territory A. Peresan, A. Magrin, A. Nekrasova,V.G. Kossobokov & G.F. Panza Dipartimento di Matematica e Geoscienze ICTP SAND Group www.ictp.it Introduction •Rigorous and objective testing of seismic hazard assessments against the real seismic activity must become the necessary precondition for any responsible seismic risk estimation. •NDSHA is based on the realistic modelling of ground motion. •PSHA and NDSHA maps for Italy are cross-compared and tested against the real seismicity. NDSHA • physical modeling of generation and propagation of seismic waves • different scale: 6˚ 7˚ 8˚ local scale national scale MOH - AMPLIFICAZIONE 9˚ 10˚ 11˚ 12˚ 13˚ 14˚ 15˚ 16˚ 17˚ 18˚ 19˚ 20˚ 48˚ 48˚ 47˚ 47˚ 46˚ 46˚ 45˚ 45˚ 44˚ 44˚ 43˚ 43˚ 42˚ 41˚ scenario earthquakes synthetic seismograms 42˚ DGA (g) 0.488 41˚ 0.300 0.150 40˚ hazard map 40˚ 0.080 39˚ 39˚ 0.040 0.020 38˚ 38˚ 0.010 0.005 37˚ 37˚ 36˚ 36˚ 6˚ 7˚ 8˚ 9˚ 10˚ 11˚ 12˚ 13˚ 14˚ 15˚ 16˚ 17˚ 18˚ 19˚ 20˚ national Thursday, 17 November 2011 local (Panza et al. 2001, Panza et al., 2012) 14 NDSHA: national scale Regional polygons Earthquake catalogue Seismogenic zones Structural models Cellular sources Receivers Synthetic events Synthetic seismograms Extraction of significant ground motion parameters Seismogenic nodes National scale: Sources Historical seismicity Tectonic setting 6˚ 7˚ 8˚ Seismogenic nodes 9˚ 10˚ 11˚ 12˚ 13˚ 14˚ 15˚ 16˚ 17˚ 18˚ 19˚ 20˚ 48˚ 48˚ 938 937 47˚ 905 902 901 47˚ 204 903 261 201 260 904 46˚ 907 909 908 45˚ 906 203 259 46˚ 262 263 257 911 913 910 44˚ 915 916 921 43˚ 264 912 254 44˚ 255 917 919 918 253 252 920 265 923 922 42˚ 45˚ 256 914 924 928 41˚ 43˚ 251 42˚ 925 927 41˚ 926 931 40˚ 929930 39˚ 934 38˚ 933 40˚ 39˚ 932 936 38˚ 935 37˚ 37˚ 36˚ 36˚ 6˚ 7˚ 8˚ 9˚ 10˚ 11˚ 12˚ 13˚ 14˚ 15˚ 16˚ 17˚ 18˚ 19˚ 20˚ ZS9 (Gruppo di Lavoro., 2004) (CPTI04, 2004; Zivcic et al., 2000; Markus et al., 2000) (Gorshkov et al., 2002, 2004) National scale: Structures 6˚ 7˚ 8˚ 9˚ 10˚ 11˚ 12˚ 13˚ 14˚ 15˚ 16˚ 17˚ 18˚ 19˚ 20˚ 48˚ 48˚ 47˚ 47˚ 14 46˚ 13 11 46˚ 252 16 10 12 45˚ 45˚ 9 44˚ 44˚ 8 7 43˚ 43˚ 6 42˚ 41˚ 42˚ 5 4 40˚ 3 39˚ 2 38˚ 41˚ 40˚ 39˚ 38˚ 1 37˚ 15 36˚ 37˚ 36˚ 6˚ 7˚ 8˚ 9˚ 10˚ 11˚ 12˚ 13˚ 14˚ 15˚ 16˚ 17˚ 18˚ 19˚ 20˚ (Costa et al., 1993) National scale: Results PGD PGV (Panza et al., 2012) DGA Introduction of recurrence in NDSHA Regional polygons Earthquake catalogue Seismogenic nodes Seismogenic zones Structural models Seismic sources Receivers Synthetic events Recurrence polygons Synthetic seismograms Extraction of significant ground motion parameters Recurrence of maximum ground motion Ground motion maps for specified return periods 1. characterization of sources in terms of recurrence to; 2. all events from minimum up to maximum magnitude of the source must be computed. (Peresan et al., 2013) Sources recurrence: G-R estimation The regions for definition of G-R parameters (“a-zones”) for strong earthquakes. (Kronrod, 2011) Recurrence of maximum ground motion: DGA (Peresan et al., 2013) Ground motion maps with fixed return period T=475 (Peresan et al., 2013) T=2475 Comparison with probabilistic maps: T=475 anni Neo-deterministic DGA vs. probabilistic PGA, T = 475 years 0.6 0.5 PGA [g] 0.4 0.3 0.2 0.1 0 0 0.1 0.2 0.3 0.4 DGA [g] http://zonesismiche.mi.ingv.it/mappa_ps_apr04/italia.html 0.5 0.6 Comparison with probabilistic maps: T=2475 anni Neo-deterministic DGA vs. probabilistic PGA, T = 2475 years 0.6 0.5 PGA [g] 0.4 0.3 0.2 0.1 0 0 0.1 0.2 (Meletti, Montaldo, 2007) 0.3 0.4 DGA [g] 0.5 0.6 Comparison of the seismic hazard maps and real seismicity for the Italian territory (a) Iobs (d) I DGA (b) I PGA10% (e) I DGA10%(c) I PGA2% (d) I DGA (f) I DGA2% DBMI04 (Stucchi et al., 2007) V V VI VII VIII IX X XI Relation between IMCS, PGA(g) and DGA(g) (Panza et al. 2001) Comparison of the seismic hazard maps and real seismicity for the Italian territory I PGA10% (%) PGA2% (%) DGA (%) XI 100.00 33.75 28.06 X 81.45 73.87 50.92 IX 89.35 90.82 81.56 VIII 102.58 100.07 98.14 Sum of prediction errors (Peresan et al., 2013) Conclusions • the introduction of a return period causes a systematic underestimation of the expected ground motion • the predictions (DGA, PGA2%, PGA10%) provide rather conservative estimates • the NDSHA maps appear to outscore the PSHA ones in terms of efficiency in predicting ground motion References • G. Costa, G.F. Panza, P. Suhadolc, and F. Vaccari. Zoning of the Italian territory in terms of expected peak ground acceleration derived from complete synthetic seismograms. Journal of applied geophysics, 30(1):149–160, 1993. • A.I. Gorshkov, G.F. Panza, A.A. Soloviev, and A. Aoudia. Morphostructural zonation and preliminary recognition of seismogenic nodes around the Adria margin in peninsular Italy and Sicily. Journal of Seismology and Earthquake Engineering, 4(1):1–24, 2002. • A.I. Gorshkov, G.F. Panza, A.A. Soloviev, and A. Aoudia. Identification of seismogenic nodes in the Alps and Dinarides. Bollettino della Società geologica Italiana, 123(1):3–18, 2004. • Gruppo di Lavoro. Redazione della mappa di pericolosità sismica prevista dall’Ordinanza PCM 3274 del 20 marzo 2003. 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