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
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INGV, Milano-Roma, aprile 2004, 65 pp, 5 enclosures, 2004
•
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•
T. Kronrod. Estimation of G-R law parameters for strong earthquakes in Italy. Technical report,
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•
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•
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•
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•
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•
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