Tom Wilson1; Andrew King2; Carol
Stewart1; Graham Leonard2; Natalia
Deligne2; Peter Baxter3; CoUGARS1
1:University of Canterbury, New Zealand
2: GNS Science, New Zealand
Overview
 NZ Research programme
 General context
 Focus on building impacts


Observations from field surveys
Laboratory experiments
 Impacts to urban environments...what is important?
 Agriculture loss modelling - tephra
New Zealand Research Programme
 Mid 1990’s – present
 need to develop a greater evidence-base of volcanic
impacts to enhance preparedness and mitigation
decision making (particularly for ash fall)

1995-96 Ruapehu eruption catalyst
 Riskscape and DEVORA Projects (2010- present)
 Quantitative volcano loss model – initial focus on
Auckland, but intended to build to national coverage
Research Context – Ash Impact Research
•
•
•
Over the past 20 years our New Zealand research
group (and collaborators) have aimed to undertake a
sustained and systematic approach to volcanic impact
assessment
- critical infrastructure: electricity, water supplies,
wastewater, land and air transport,
telecommunications
- ash cleanup and disposal
- primary industries, e.g. agriculture
- social impacts
- emergency management
Reconnaissance trips to impacted areas to bring
lessons home
Followed by laboratory testing of critical infrastructure
components...VAT Lab
Recon Trips: by volcano & year visited
Redoubt 1996; 2010
Eldfell (Heimaey) 2008
Shinmoedake
2011
Etna
2003
Sakurajima
2001
Pacaya
2010
Pinatubo
2007
Merapi
2006
Tungurahua
2005; 2010
Lapevi
2003-05
Ruapehu
1995-96
Puyehue Cordon-Caulle
2012
Hudson
2008
Chaiten
2009
What pops up time after time...
 Volcanic ash falls are often regarded as exotic events
(mysterious) which are rarely planned for
 Health (most important!)
 What does ash do to me….to my children?
 What will ash do to water supplies?
 What impact will it have on food?
 Farming
 What will ash do to my animals and crops?
 How can I remediate the damage?
 How much Fluoride is in the ash?
 Infrastructure
 Clean up – difficult and expensive (time & $$ )
 Didn’t expect those impacts.
 Wish we had planned for this…
 Business Disruption
 Difficult to clean up. Is it safe to remain?
 How do we get the tourists back?
 Government level – what are the losses?
Which hazard intensity?
 Loading?
 Thickness?
 Duration of fall?
 Grainsize?
 Agriculturally available
chemistry?
Building Damage Observations
 Structural damage from ash loading has been
rarely observed by our group
 Acknowledging Rabaul, Pinatubo, etc
 Futaleufú, Chile (Chaiten, 2008)
 75 mm + snow
 Long span roof (gym) began deforming (not
built to snow code)
 Villa La Angostura, Argentina (PCC, 2011)
 75-100 mm + rain
 Non-snow code (pre-1980’s) residential
houses require extra bracing
 Shinmoedake, Japan (Shinmoedake, 2011)
 Long span roof (agricultural feedlot)
collapsed
PUYEHUE
CORDON-CAULLE
CHAITEN
HUDSON
Ash damage to buildings
Structural

Observations rare
2. Envelope: non-structural elements

Gutter damage is very common (when fitted)

Corrosion of metal roofs
3. Fittings : systems which allow building to function

HVAC systems vulnerable to disruption
4. Contents and Plant

Contamination of the interior space

Clean up is expensive + on-going
1.


Actual loss is dependent on all these elements,
which act as an interdependent system
Role of mitigation? i.e. cleaning?
Chasing D1: Laboratory experiments
 Dynamics ash deposition on roofs – what actually
happens?
 How vulnerable are gutters?
 Are metal roofs vulnerable to roof corrosion?
Behaviour of ash on sheet metal roofs +
gutter vulnerability
Behaviour of ash on sheet metal roofs + gutter
vulnerability
Hampton, S.J., Cole, J.W., Wilson, T.M., Wilson, G., (in prep). Volcanic ash loading on
variable pitch roofs and gutters: implications for risk assessment
Volcanic ash accumulation and shedding relative to roof
pitch (50 mm/40kg/m2 deposition of ash)
Hampton, S.J., Cole, J.W., Wilson, T.M., Wilson, G., (in prep). Volcanic ash loading on
variable pitch roofs and gutters: implications for risk assessment
Sheet metal roof corrosion from ash deposition
Oze, C., Cole, J.W., Scott, A., Wilson, T.M., Wilson, G., Gaw, S., Hampton, S.J., Doyle, C., Li,
Z., (accepted). Corrosion of metal roof materials related to volcanic ash interactions,
Natural Hazards, DOI 10.1007/s11069-013-0943-0
 No significant corrosion
was macroscopically or
microscopically present
on any roofing surfaces
despite the presence of
corrosive salts after a
duration of 30 days
 Suggests ash-leachaterelated corrosion is not a
major or immediate
concern in the short term
(~1 month)
 Ash still present after
brushing – suggesting
power washing might be
required
Oze, C., Cole, J.W., Scott, A., Wilson, T.M., Wilson, G., Gaw, S., Hampton, S.J., Doyle, C., Li,
Z., (accepted). Corrosion of metal roof materials related to volcanic ash interactions,
Natural Hazards, DOI 10.1007/s11069-013-0943-0
NZ approach to ash fragility functions for
buildings?
 Currently
 Very basic: long span vs. short span
 Planned Work (<12 months)
 Direct structural damage from ash and PDC
 Is this really significant? What is the likelihood of ash
deposition which might cause structural losses
 Guided by the NZ snow loading code


Light industrial = problem
Residential = ok
 Building Vulnerability Schema
 Roof structure information
 Indirect impacts
Beyond buildings

Buildings are only a small portion of the problem.
Agriculture
Clean up
Tourism




Aviation...
Business continuity impacts


Critical infrastructure disruption
Impacts to the built
environment from large
silicic tephra falls
 New Zealand and
Patagonia share similar:
 Latitude
 Volcanoes
 Climate (esp. west)
PUYEHUE
CORDON-CAULLE
CHAITEN
HUDSON
Jaccobacci
40°S
PCC
Villa La Angostura
Bariloche
CHAITEN
Chaiten
Futaleyufu
Esquel
Trevelin 2008 Chaiten Eruption
•
•
•
•
HUDSON
Puerto Ibanez
VEI 4
0.5-1.0 km3 bulk volume
150,000km2 affected
Rhyolite
1991 Hudson Eruption
• VEI 5
• 4.3 km3 bulk volume
• 100,000km2 affected
• Trachyandesite-rhyodacite
Chile Chico
Los Antiguos
References:
• PCC: Villarosa et al. unpub
data
Tres Cerros
• Chaiten: Watt et al. 2009;
Puerto San Julian
Alfano et al. 2011
• Hudson: Scasso et al. 1994
Perito Moreno
50°S
2011 Puyehue Cordon-Caulle
Eruption
• VEI 4
• ~4.5 km3 bulk volume
• 150,000km2 affected
• Rhyodacite
2008 Chaiten eruption, Chile
75 mm of ash fall induced infrastructure failure in
Futaleufu, Chile (2,000 residents - temporary
evacuation)
• Water supply compromised
• Power supply cut
• Roads disrupted by thick ashfalls
• Health concerns
Compounded effects
Evacuation duration: 1-12 months
Eruption
HUDSON 1991
PUYEHUE CORDONCAULLE 2011
CHAITEN 2008
Town Affected
Puerto
Ibanez
Chile Chico
Los
Antiguos
Perito
Moreno
Tres
Cerros
Distance from Vent
(km)
90
120
125
175
473
Puerto
Chaiten Futaleyufu Trevelin
San Julian
545
11
75
100
Esquel
110
Villa La
Bariloche Jaccobacci
Angostura
44
90
231
Thickness of
ash fall (mm)
Ground
common
20
100
80
20transportation:
40
5
20most30
15
10
150
40
35
Ash hazard Duration of
and often longest disruption.
character- main ash fall 4 days 4 days 4 days 4 days 2-4 days 2-4 days 3 days 6 days 4 days 2-3 days 5-6 days 5-6 days 5-6 days
istics
Roads (and properties) require clean up 
Remob of
5-10
5-10
0.5-4
6-18
6-18
6-12
6-12
>18
costly
and
ash
15 years 15 years 15
years 15
yearstime consuming
1-2 years
years
years
years
months months months months months
(duration)
Power
Water
Critical
Infrastructure
Ground
Transport
Waste-water
& Sewage
Telecom
Municipal
Cleanup
Undertaken
Duration
DURATION
Official Evac
Hour(s)
Evacuation Self evac –
of Day(s)
immediate
population Self evac long term
Month(s)
Year(s)
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes Yes Yes Yes Yes Yes
Electrical + Water: high
dependence  high disruptive
Yes
Yes
No
No
No
No
No
impact
SEVERETY
No
No
No
No
No
Few isolated issues
<50% <50% <30% <25% >75% <5% 100% >50% <5% <5% <20% <5% <20%
Widespread outages
design
<50% Yes
Yes
Yes >75% Yes >50% System
----key factor
???
--Total disruption
Yes
General findings for infrastructure
 Loose relationship with ash thickness/load, but strongly
influenced by:
 system design
 level of planning
 adaptive capacities + mitigation actions (clean ash off
roof)
 The complex characteristics of volcanic ash can create a
range of possible direct and indirect impacts
 Possibly leading to complex, cascading effects
 Individual case-by-case assessment approach probably
most appropriate
Kaharoa
Eruption Model
• Based on 1315 A.D.
Kaharoa Eruption from
Tarawera Volcano
Exposed Dairy Farms
Volcanic Fragility Functions for Pastoral Farming
Fragility functions
Relate hazard
intensity (X) and
fragility (Y)
Probability can be
loss, replacement,
etc.
Link is then made
between hazard and
inventory via
fragility function
Seasonal Vulnerability
• Dairy farms carry out
different activities
throughout the year
• Creates variable
vulnerability throughout
the year
Seasonal Vulnerability
• Seasonality Coefficient
– only applicable to production
loss
•
•
•
Red = highly vulnerable (1.0)
Yellow = moderately vuln. (0.75)
Green = some vuln. (0.5)
Estimated Losses
Eruption Scenario
Number of
Exposed Dairy
Farms
Estimated Loss
High Vulnerability
Low Vulnerability
Kaharoa
8,760
$2,970 million
$2,440 million
Inglewood
4,884
$1,120 million
$911 million
Ruapehu
2,368
$1.34 million
$0.91 million
(trace ash included)
• Compare to 1 in 100 year Manawatu flood loss estimates
of $32.7 million (assessed loss immediately after event)
Volcanic Ash Testing Lab
 Identified some components/systems are
vulnerable, or might be vulnerable
 Laboratory testing in controlled
environment




Electricity – flashover (AELG-19)
Water – coag/floc
Computers – damage & function loss
GenSets – filter fragility/replacement
Contaminated with
3mm ash
Contaminated with 3mm ash
Clean String
Indirect impacts -- Evacuations
 Official evacuations rare
Anxiety of ash
contamination
of water
supplies
Airborne ash
= anxiety of
respirable
hazard
 But self-evacuation very
common
 Persistence of ashy
conditions (direct or
reomob) will influence
duration of evacuation
 Few evacuation from fear
of roof collapse
 insufficient ash loads
Evacuation
following
Ash Falls
Critical
Infrastructure
failure
(power, water,
etc.)
Anxiety of ash
contamination
of food
supplies
 Remobilisation of ash (esp. on regional scale) is just as
disruptive as primary fall as it extends duration of impact
 Infrastructure networks (electricity, road, water)
 Agriculture (highly sensitive)