First International Conference on MOLDAVIAN RISKS – FROM ...

<strong>First</strong> <strong>International</strong> <strong>Conference</strong> on MOLDAVIAN RISKS - FROM GLOBAL TO LOCAL SCALE
16-19 May 2012, Bacau, Romania
A SEISMIC RISK ANALYSIS FOR VRANCEA AND BACAU
COUNTIES, BASED ON SELENA AND GIS SOFTWARE
Dragos Toma Danila
National Institute for Earth Physics, Magurele, Ilfov, Romania
Corresponding author: Dragos Toma Danila, toma@infp.ro
Abstract: In the last years, thanks to the implementation of the ShakeMap software in realtime
at the National Institute for Earth Physics (NIEP) and within the DACEA Project, a
system that computes damage and loss estimates in (near) real-time for the Romanian-
Bulgarian border region was installed at NIEP, producing data and maps, on Romanian
side - for 7 counties. But the system was also designed so that it has the capability to allow
extending and upgrading the database, for all Romanian counties and taking into
consideration the permanent evolution of building stock and population. The main purpose
of this paper is to present both the integration mode and the results obtained by adding new
counties into the implemented system, and also to present best ways for a GIS
representation of the estimated damage. Of great interest is that the new counties –
Vrancea and Bacau, are right on top of the active seismic area of Vrancea, compared to the
previous analyzed 7 counties that are more than 100 km away from the epicentral area. For
damage computation it was used the open-source software SELENA (Seismic Loss
Estimation using a Logic Tree Approach), with the real-time module based on PGA and Sa
values at 0.3 and 1.0 seconds, provided by a 10 by 10 km grid produced by ShakeMap. Of
course, for results were simulated significant previously recorded earthquakes: the ones on
4 march 1977 (Mw 7.4), 30 august 1986 (Mw 7.1) and 30 may 1990 (Mw 6.9). The static
database included number of buildings from the 2002 census, at UAT (administrativeterritorial
unity) level. Buildings were classified in 55 individual types, each with a specific
capacity and fragility curve. The method used to obtain damage probabilities was the more
recent Improved Displacement Coefficient Method (I-DCM). The spatial characteristic of
the generated output provided a good basis for the use of GIS tools, which added important
contribution to how data is visualized and used for planning and intervention purposes.
There are many practical sides of the paper: first of all is that based on past events it is
illustrated how the damage might look like nowadays in a very exposed area and what are
the risks to be dealt with. Also, the certain accuracy of the loss assessment is validated, so
that the new counties can be included in the real-time damage estimation system at NIEP.
Key words: seismic risk, Selena software, Bacau & Focsani counties, damage estimation, GIS.
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