1. Mortality Patterns in
Earthquakes: the Example
of L'Aquila, 6 April 2009
David Alexander
University College London

2. "Now, what I want is, facts. Teach
these boys and girls nothing but Facts.
Facts alone are wanted in life. Plant
nothing else, and root out everything
else. You can only form the minds of
reasoning animals upon Facts: nothing
else will ever be of any service to
them. This is the principle on which I
bring up my own children, and this is the
principle on which I bring up these
children. Stick to Facts, sir!"
Thomas Gradgrind in Hard Times
by Charles Dickens

3. Towards an evidence-based approach
to earthquake epidemiology

4. The earthquake
03.32 hrs, Monday 6 April 2009
Magnitude: Mw 6.3
Duration: circa 25 sec.
Acceleration on hard rock: 0.3g
Acceleration on sediments: 0.7-1.0g
Part of an earthquake swarm
that began in October 2008.

5. Deaths: 308
Injuries: 1,500
(202 serious,
& 898 triaged)
Homeless people:
67,000
Tent camps: 171
Tents: 5,700 (for
8 people each)

6. Deaths in the L'Aquila earthquake:-
• dominated by age groups 20-29 and 70+
• an excess of females, especially
in age groups 30-39 and 70-79
• the excess of females cannot be
explained purely by demographics
• if mortality had followed the M/F and
age-group distribution of the population,
it would have been 168, not 308.

7. Deaths in the L'Aquila earthquake:-
• death/injury ratio = 0.20 (low)
• case fatality rate = 0.17 (low), 0.41-
0.60 for serious injuries (rather high)
• ratio of serious to all injuries = 0.13
(50-70% of the expected value).

8. Fatal
injuries
Serious high ratio
injuries
low ratio
All
injuries low ratio

9. After more than 30 years of study,
the relationship between injury and
damage patterns is still poorly understood.

10. Characterising
damage

11. Typical forms of damage in RC
Column breakage
Incipient collapse of intermediate floors
caused by lack of stiffness in structure.

12. Typical forms of damage in RC
Two deaths
Collapse of intermediate floor caused
by battering by adjacent retaining wall.

13. Typical forms of damage in RC
Compressed
ground floor
Collapse of 'soft storey' ground
floor which had insufficient stiffness.

14. Typical forms of damage in RC
Racking
failure
Detachment, fragmentation
and expulsion of infill walls.

15. Typical forms of damage in URM
Load-bearing walls disintegrate at angles.

16. Typical forms of damage in URM
Excessively heavy roof in RC: subsides.

17. Mid-floor damage to multi-occupancy bldg:
Intertia effect
Interaction = damage
Lack of stiffness in frame
Basal acceleration

18. Unexpected earthquake
Mild Severe Catastrophic
impact impact impact
Very Fall of
Partial Total
limited heavy
collapse collapse
damage objects
Remain Seek
Seek in situ potential
place of Rush cavity
refuge outside
Lightly Seriously
Uninjured Killed
injured injured
Absolute immobility Frantic egress

19. Detachment of façade elements
and fall of roof tiles.

20. Algeria 2003 L'Aquila 2009
Stairwell
collapse

21. Q E
Poor quality Proximity
Injuries
Q building
(low seismic
to epicentre
and fault E
resistance) rupture Deaths
Concentration
T S
of casualties
T Topographic
amplification
Sedimentary
amplification S C
C = f { E,Q,S,T }

22. A practical earthquake epidemiology
Focus Potential benefit to...
Self-protective
How, where behaviour
and why
people died; Urban search
who they were; and rescue
how they (USAR)
reacted to
the earthquake Hospital
mass-casualty
response

23. Behavioural influence on casualties
Active behaviour:
• journey to and from work
• recreational activities, etc.
• family life at home
Passive behaviour:
• sleeping at night
• role, efficiency and rapidity of
search and rescue and medical
assistance after the earthquake.

24. The ratio of deaths to collapsed
buildings varies from 8:100 to 32:100
Entrapment increases the risk
of death by 35-100 times
• respiratory difficulties caused by
pressure of fallen objects on the thorax
or ingestion of large amounts of dust
• 2-6 hours after the earthquake fewer
than half of trapped people are still alive.

25. Percentage of people trapped alive
under the rubble of collapsed buildings
0
100
50
Hours
0.5 1 3
12
Critical period
Survival time
Days
1 2 3 45 7 10 15
Source: Coburn and Spence (2002)

26. These are the people
who died in the
6th April 2009
L'Aquila (central Italy)
earthquake

36. Abruzzo Region
Preturo L'Aquila
Tempera Province
L'Aquila Paganica
Epicentre
Poggio
Bazzano San
di Roio
Roio Gregorio
Piano Pianola Onna
Poggio
Bagno Picenze
Tornimparte Fossa San Demetrio
Lucoli ne' Vestini San Pio
Villa delle Camere
Sant'Angelo
10 km

37. Location of deaths (by town), n=308
1
8
5
202
2 1 1
2 39 8
5
1 1
2 4
1 3 5
17

38. Deaths
Sant'Angelo di Bagno
Poggio di Roio
Civita di Bagno
Tornimparte
Pianola
Fossa
Poggio Picenze
Tempera
Villa Sant'Angelo
L'Aquila
0 50 100 150 200

41. Null hypothesis: no factors of age
or gender increased the probability
of being killed in the earthquake.

47. Average Age of Victims (by town), n=308
73.0
66.5
56.8
51.1
66.5 57.0 74.0
69.5 60.6 60.6
22.8
8.0 77.0
83.0 52.7 56.0
26.0 26.0 61.6
57.5

51. L'Aquila City: location of deaths of 30-39-yr olds
6
1
5
2
2
2 2
2
4 2
4
1 Total collapse of house, single death: 3F
2 2 Collapse of house kills entire family: 6F/2M
2 3 Total collapse of house: slow death: 1F
Male 1 1 4 Partial collapse of house: 2M
Female 3 5 Crushed by beam: 1F
6 Not known: 1F

53. Area of roof and Area of
stairwell collapse: comparatively
limited casualties light damage
and no
casualties
Area of Area of sporadic
topographic damage and
amplification, few casualties
with major
damage and
casualties
500 m

54. To NE:
unreinforced
masonry
All victims in
buildings
L'Aquila city To SW:
centre area reinforced
n=186 concrete
buildings
Male
Female

57. Pensioners'
disaster area
Students' Topographic
amplification
disaster area
Roof and
stairwell collapse
Sporadic
damage
Light damage
(no deaths)

60. Older people were more
aware of the danger but less
willing or able to react to it.
Females, especially old ladies, were
more inclined to passive behaviour.
Males, especially old men, were more
inclined to try to get out of the building.
Old people were more
inclined to behave passively.

61. Implications
• self-protection potentially saves lives
• inability or unwillingness to
react increases the danger
• women more inclined to
treat house as refuge
• old men better at self
protection than old ladies?.

62. Conclusions

63. Disproved hypotheses:-
• men and women were doing
different things when quake struck
• clustering of male and female deaths
• people died more readily
in URM than RC buildings
• average age of victims
higher in small settlements
• women died trying to save
children and men did not.

64. In the L'Aquila data set, above
the age of 70 there were 19-24%
more deaths than predicted by local
demographic profiles, amounting
to 59-74 individuals out of 308.
Old people - calculated excess
over the demographic predictor:-
• Women: 40 (13% of total mortality)
• Men: 19 (6.2% of total mortality).

66. "More research is needed"

67. Thank you
very much
for
listening!
David.Alexander@ucl.ac.uk
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