Beşinci Ulusal Deprem Mühendisliği Konferansı, 26-30

SEISMIC RISK EVALUATION ON A LARGE SCALE:
PROBABILISTIC APPLICATION
François DUNAND 1, Eric FOURNELY2 2,3, and Rostand MOUTOU PITTI2,3
The last events occurring in Haiti, Chile, New-Zealand, Japan..., prove, if necessary, that populations
and built heritage have to be guard against destructive earthquake phenomena. Indeed, despite the low
occurrence of large earthquakes in the French metropolitan territory, located in moderate seismicity
area, significant seismic events can occur like those that occurred in the last century in Chamonix
(1905), in Lambesc in Provence (1909) and Annecy (1996).
This work relates the evaluation of seismic risk to large scales in the Nice-Côte d’Azur
Community (CANCA). In this context, it is proposed an assessment method of seismic risk for the
Agglomeration of Nice Côte d'Azur Community (CANCA), Figure 1 (a). In the case of Nice city, the
vulnerability areas identified during the Risk-UE project (2003) are used. The CANCA community,
located in southeast of France, is composed of 27 municipalities with growing population and an
important economy. In this case, more than 500 000 people live in this region and occupy an area of
394 square kilometres, including the city of Nice and its surrounding.
0 1,5 3
6
9
kilometres
12
local intensity hazard
7,3 – 7,5 reference
return
7,5 – 7,6
7,6 – 7,8 period:
475
7,8 – 7,9
years
7,9 – 8,1
0 1,5 3
6
9
kilometres
12
local seismic hazard
Insignificant
Low
Moderate
High
Figure 1. (a) Seismic regional hazard map in intensity for CANCA territory and a return period of 475 years.
(b) Hazard seismic local map of CANCA territory.
1
Dr, GEOTER Alpes – Fugro Group, Savoie Technolac, Le Bourget du Lac, France, [email protected]
Dr, Clermont Université, Université Blaise Pascal, Institut Pascal, Clermont-Ferrand, France
3
Dr, CNRS, UMR 6602, Institut Pascal, Aubière, France, [email protected],
[email protected]
2
1
Firstly, census data used for the realization of a seismic risk assessment in large scale is conducted,
Figure 1 (b). Two types of data are considered: on one hand, BD-TOPO data from the IGN (French
geographic institute) providing the outline of each building and their geographical location and
allowing the consideration of the local hazard and the vulnerability regions is considered; on the other
hand the census data from 1999 and 2006 of INSE (National institute of statistics and economic
studies) at the level of the town, for an analysis performed by using an uniform random distribution of
the types of structures is taken into account.
The vulnerability of the structures is then estimated using the two precedent approaches. For
analysis by building, the vulnerability is obtained from the distribution of buildings by similar district
vulnerability (downtown, Central Business District, residential areas...), which is based on the
orthophotography study. In the case of statistical analysis at the level of municipalities, the
vulnerability is determined from building typology based on the age and the height of buildings as
well as the type and the size of municipalities (city, village), Table 1.
Table 1. Generic distribution of vulnerability in CANCA
vulnerability level
Typology
appartment buildngs ( more than single dwelling)
individual dwelling
number of storeys
1 to 2
1 to 5
6 to 9
>9
years of built
< 1915
1915 - 1948
1949 - 1967
1968 - 1974
1975 - 1981
1982 - 1989
>1989
< 1915
1915 - 1948
1949 - 1967
1968 - 1974
1975 - 1981
1982 - 1989
>1989
< 1915
1915 - 1948
1949 - 1967
1968 - 1974
1975 - 1981
1982 - 1989
>1989
< 1915
1915 - 1948
1949 - 1967
1968 - 1974
1975 - 1981
1982 - 1989
>1989
less than 600 building
mid size municipalities
municipalties
moderate
moderate
moderate
low
low
low
low
high
high
moderate
moderate
low
low
low
moderate
moderate
low
low
low
low
low
high
high
moderate
moderate
low
low
low
high
high
moderate
moderate
moderate
low
low
high
high
moderate
moderate
moderate
low
low
Nice
moderate
moderate
low
low
low
low
low
high
moderate
moderate
low
low
low
low
high
high
moderate
moderate
moderate
low
low
high
high
moderate
moderate
moderate
low
low
Based on the intensity probabilistic seismic risk curve, and taking into account the local risk, a
probabilistic calculation of seismic risk is carried out. It leads to an evaluation of the annual
probability of various levels of damage, individual annual probability of mortality and hope amongst
victims. The obtained results are compared and analyzed, as well on the level of human losses as the
possible damage probabilities.
REFERENCES
RiskUE (2003) An advanced approach to earthquake risk scenarios with applications to different european towns, Projet
Européen, EVK4-CT-2000–00014.
Giovinazzi S, Lagomarsino S (2006) Macroseismic and mechanical models for the vulnerability and damage assessment of
current buildings, Bulletin of Earthquake Engineering, 4(4): 415-443
Martin C, Secanell R, Viallet E, Humbert N (2008) Consistency of PSHA Models in acceleration and intensity
by confrontation of perspective models to available observations in France, CSNI Workshop on recent findings
and developments in PSHA methodologies and applications, Lyon
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