at least 3000 19 000 11.09.2001T error attack against W T C , Pentagon andother buildings US A
300 23.10.1983Bombing of US Marine barracksand French paratrooper base in Beirut Lebanon
3 0 0 6 1 2. 0 3. 1 9 93 S eries of 1 3 bomb attacks in M umbai India
270 138 21.12.1988PanA m Boeing 7 4 7 cras hes at Lockerbiedue to bomb explos ion UK
253 07.08.1998T w o s imultaneous bomb attacks on USembas s y c omplex in Nairobi Kenya
166 145 19.04.1995Bomb attack on government building inOklahoma C ity US A
127 45 23.11.1996Hijacked Ethiopian A irlines Boeing 7 6 7-2 6 0ditched at s ea Indian Ocean
118 13.09.1999Bomb explos ion des troys apartmentblock in Mos cow Russia
1 0 0 0 4. 0 6. 1 9 91 A rs on in arms w arehous e in A ddis A baba Ethiopia
100 6 31.01.1999 Bomb attack on Ceylinco House in Colombo Sri LankaVictims^1 Insuredlosses 2(^1) Dead or missing (^2) Excluding liability losses; in USD m, at 2001 price level
Date Event Country
Table 1.5: Insured losses and fatalities due to malevolence in the period 1988 – 2001 (Swiss Re (2001)).
As for the natural hazards, acts of malevolence are of a very localized nature and due to the
circumstances of the events often have significant consequences. In Table 1.6 the estimated
economic losses following the collapse of the World Trade Centre twin towers are
summarized. In the table the scenarios Low and High correspond to different models for
assessing the consequences. However, it is clearly seen that the consequences go far beyond
the direct losses of the buildings and the people inside. Actually the total costs are in the order
of four times higher that the direct loss of the buildings themselves.
Consequence TypeRescue & Clean-Up Low High1.7 1.7
PropertyWTC Towers 4.719.4 19.4
Other Destroyed BuildingsDamaged Buildings 2.04.3
Inventory 5.0
FatalitiesInfrastructure 3.4 5.0 5.0
Lost RentsImpact on Economy 1.27.2 64.31.2
Total(in billion USD) 34.5 91.6
Scenario
Table 1.6: Estimated loss summary for the failures of the WTC twin towers (Faber et al. (2004)).
Risks Due to Structural Failures
Considering structural failures, several studies point to the fact that these on an overall scale
contribute only insignificantly to the fatality rate. In Kvitrud et al. (2004) a study of structural
failures in the offshore sector indicates that the annual probability of structural failures
leading to severe or total losses of facilities is in the order of 73510 ^4 a number which can
be assumed to cover other types of structures of the same importance such as major
infrastructures and power supply facilities. Structural failures not resulting in fatalities or
injuries may be assumed to occur at a somewhat higher frequency than compared to these
numbers, since such events in many countries they do not have to be reported. Furthermore, in
the same study it is found that given a structural failure the probability of a fatality is in the
order of 0.05.
When evaluating the acceptability of risks associated with an engineering system to third
party individuals the inescapable minimum risk that has to be accepted by any individual