UNDER THE CLOUD
Tom Wilson
University of Canterbury
Managing Volcanic Ashfall Impacts
Outline




Volcanic Risk
Impact mapping
Evac analysis
Exercise – cost/benefit with a scenario
Volcanic Risk Management

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
Eruptions of high risk volcanoes are usually
preceded by a phase of unrest.
Sound management of this phase may help save
many lives and reduce the economic impact of
eruptions
At present, a wide variety of qualitative or semiquantitative strategies are used, and there is not yet
a commonly accepted quantitative and general
strategy.
Marzocchi W., Newhall C., Woo G., (2012) The Scientific Management of
Volcanic Crises. Journal of Volcanology & Geothermal Research 247-248
(2012) 181-189
Naughty Volcanoes


“Pre-eruptive processes are extremely complicated,
with many degrees of freedom nonlinearly coupled,
and poorly known, so scientists must quantify eruption
forecasts through the use of probabilities. On the
other hand, this also forces decision-makers to make
decisions under uncertainty.”
Marzocchi W., Newhall C., Woo G., (2012) The Scientific Management of Volcanic
Crises. Journal of Volcanology & Geothermal Research 247-248 (2012) 181-189
Intensity of monitoring parameters
Challenge: Forecastability
Major Eruption
(Mount St. Helens, 1980;Pinatubo 1991)
Decision Window when civil
officials/emergency managers face critical
decisions about public safety – before the
volcanic outcome is known.
Time
C.D. Miller, USGS
Intensity of monitoring parameters
Challenge: Forecastability
Decision
Window
MAJOR ERUPTION:
MSH 1980, Pinatubo
1991, Chaiten, 2008
EVENTUAL ERUPTION:
Soufriere Hills 1995
(Montserrat)
Variable unrest &/or
small eruptions
RETURN TO QUIET:
Akutan 1996,
Cotopaxi 2002
Time
RETURN TO QUIET:
Guadeloupe 1976-77
Long Valley CA
C.D. Miller, USGS
NEEDS REWORDING


The choice to take or not to take a mitigating action
is typically based on qualitative information and
personal judgment during a crisis, rather than on
fully quantified information including all
uncertainties and the quantified pros and cons of
each planned mitigation action.
While a qualitative approach can be workable for
low to moderate risk volcanoes, the decision-making
for high risk events requires a more objective and
quantitative approach
Volcano shows signs of unrest. As an emergency manager,
what is your best short-term risk reduction strategy?
Mt Unzen,
Japan
Volcano Evacuations

Typically due to proximal hazards
 Pyroclastic
flow, lava flow, lahar
To evacuate or not to evacuate...?

In times of volcanic crisis, decisions on societal risk
mitigation have to weigh the safety benefits of
evacuation against the socio-economic costs of an
evacuation process that may last for weeks or
months (or years).
 Cost-benefit
analysis (CBA)
Principle of CBA




C = cost of protection
L = loss
L>C in adverse hazard
P = probability of adverse hazard state occurring in
time frame
Take mitigative action if P > C/L
 Do not take mitigative action if P < C/L




Optimal economic policy
P from hazard research that has been done
C and L from VRM
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CBA using VRM
C = cost of protection
L = loss to decision maker
R = average socioeconomic loss per capita
N = number of people involved in evacuation call
ν = cost of human life
E = proportion of people at risk who would owe their
lives to the evacuation call
Context – Ash Impacts
•
•
Volcanic ash is the most likely volcanic hazard to affect the most
people during an explosive eruption
Typically disruptive, rather than destructive
•
•
Although can potentially create a variety of unique impacts
Due to the wide range of potential ash sources and
characteristics it becomes complicated estimating what impacts
will be…
•
Thickness, grainsize, leachate, etc.
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 each time...
Mysterious, exotic and rarely planned for
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
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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?

What will ash do to my crops?

How can I remediate the damage?

How much Fluoride is in the ash?
Infrastructure

Unexpected. Exotic…

Wow – this ash stuff was hard to clean up.

More time & $$ than expected

Didn’t expect those impacts. Can we mitigate?

Wish we had planned for this…
Can we begin to
forecast impact
thresholds for urban
areas?
What does heavy ash fall
mean?
 Newactually
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
Esquel
Futaleyufu
Trevelin
HUDSON
Puerto Ibanez
2008 Chaiten Eruption
• 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
Perito Moreno
50°S
2011 Puyehue Cordon-Caulle
Eruption
• VEI 4
• ~4.5 km3 bulk volume
• 150,000km2 affected
• Rhyodacite
Tres Cerros
Puerto San Julian
References:
• PCC: Villarosa et al. unpub
data
• Chaiten: Watt et al. 2009;
Alfano et al. 2011
• Hudson: Scasso et al. 1994

Going forward from here


Need detailed understanding of what will
be the likely impacts at varying levels of
hazard intensity
 Heading to the lab...
 Wardman (talk and poster – this session)
Current ‘recon trip’ methodology doesn’t
allow for in-depth analysis.
 Developing local capacity = key
Thank you. Any questions?
Agricultural Impacts Overview
Soil
Physical
Impacts
Tephra
permeability
can influence
soil gas and
water
exchange
Cementation
of tephra
Radiation can
be reflected
lowering the
soil
temperature
Can also have
a positive
mulching
effect
Vegetation
Chemical
Impacts
Physical
Impacts
Increasing soil
acidity
Complete
burial of the
plant structure
Low cation
exchange
capacity (CEC)
and lack of
organic material
Overloading
of plant
causing
breakages
Can add
beneficial
amounts of some
elements
Photosynthesis
prevented
Addition of elements from
soluble salts coating tephra
and continued weathering of
the tephra
Animal Health
Chemical
Impacts
Chemical burns
Possible
uptake of any
elements in the
soil and air
that could
accumulate to
toxic levels in
plants
Could cause
damage to
root apex
Physical
Impacts
Rumen
blockages
Feed and
water sources
become
unpalatable
Tooth abrasion
Chemical
Impacts
Fluorosis from
ingestion of
tephra main risk
causing:
1. Dental lesions
2. Porous bones
3. Calcification
of tendons
4. Weight loss
Agricultural Impacts Overview
Soil
Physical
Impacts
Tephra
permeability
can influence
soil gas and
water
exchange
Cementation
of tephra
Radiation can
be reflected
lowering the
soil
temperature
Can also have
a positive
mulching
effect
Vegetation
Chemical
Impacts
Increasing soil
acidity
Low cation
exchange
capacity (CEC)
and lack of
organic material
Can add
beneficial
amounts of some
elements
Physical
Impacts
Complete
burial of the
plant structure
Overloading
of plant
causing
breakages
Photosynthesis
prevented
Addition of elements from
soluble salts coating tephra
and continued weathering of
the tephra
Animal Health
Chemical
Impacts
Chemical burns
Possible
uptake of any
elements in the
soil and air
that could
accumulate to
toxic levels in
plants
Could cause
damage to
root apex
Physical
Impacts
Rumen
blockages
Feed and
water sources
become
unpalatable
Chemical
Impacts
Fluorosis from
ingestion of
tephra main risk
causing:
1. Dental lesions
2. Porous bones
3. Calcification
of tendons
4. Weight loss
Acid burns from tephra to
Toothtomato
abrasion plants after the
2006 Merapi eruption
Agricultural Impacts Overview
Soil
Physical
Impacts
Tephra
permeability
can influence
soil gas and
water
exchange
Cementation
of tephra
Radiation can
be reflected
lowering the
soil
temperature
Can also have
a positive
mulching
effect
Vegetation
Chemical
Impacts
Increasing soil
acidity
Low cation
exchange
capacity (CEC)
and lack of
organic material
Can add
beneficial
amounts of some
elements
Physical
Impacts
Chemical
Impacts
Complete
burial of the
plant structure
Overloading
of plant
causing
breakages
Photosynthesis
prevented
Addition of elements from
soluble salts coating tephra
and continued weathering of
the tephra
Animal Health
Chemical burns
Possible
uptake of any
elements in the
soil and air
that could
accumulate to
toxic levels in
plants
Physical
Impacts
Rumen
blockages
Feed and
water sources
become
unpalatable
Chemical
Impacts
Fluorosis from
ingestion of
tephra main risk
causing:
1. Dental lesions
2. Porous bones
3. Calcification
of tendons
4. Weight loss
Tooth abrasion
Could cause
damage to
root apex
Flueck, W. (2013). Effects of fluoride intoxication on teeth of livestock due
to recent volcanic eruption in Patagonia, Argentina. Online Journal of
Veterinary Research, 14(4), 167–176.
Measuring volcanic risk
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Rationalise decision-making in situations of uncertainty
(unrest)
Scientists provide probability of the threatening event
Decision makers act through a Boolean logic (YES,NO)
The probability is a continuous number in the range 0,1
and it has to be mapped in a Boolean logic (YES,NO)
One strategy to build this mapping, linking the
probabilistic forecasting with a cost-benefit analysis
(CBA)
Sandri & Marzocchi 2013
Principle of CBA (cost benefit analysis)




C = cost of protection
L = loss
L>C in adverse hazard
P = probability of adverse hazard state occurring
in time frame
 Take
mitigative action if P > C/L
 Do not take mitigative action if P < C/L
Woo 2008; Marzocchi and Woo 2009



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C = cost of protection
R = average socioeconomic loss per capita
N = number of people involved in evacuation call
ν = cost of human life
E = proportion of people at risk who would owe their
lives to the evacuation call
Courtesy of Jan Lindsay
Exercise: “Saving Daisy”

UNREST at Taranaki Volcano
Should we make a precautionary evacuation of dairy
cows from Taranaki for a large eruption (VEI 4-5)?

Method we will use is semi-quantitative (at best...)

Why worry?


New Zealand exports ~95% of the dairy products
it produces
‘Fonterra Ltd.’ – accounts for ~30% of global dairy
trade
Financial Times
21 March 2013
Eruptive history of Taranaki Volcano

Types of eruption
Merapi style
 Plinian Style

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
138 separate ash fall-producing
eruptions between 96 and 10,150
years B.P. from Taranaki
Probability of 0.52 for an eruption
occurring in the next 50 years
(annual eruption probability:1.6%)

Turner et al. 2009


25 km
500,000 dairy cows
~0.3% of NZ GDP
Large Eruption
from Taranaki
Volcano
50 mm
100 mm
200 mm
300 mm
Stylised Isopachs from
5700 BP Inglewood
eruption
Damage States
Damage Loss of pasture (feed)
State
0
None
1
2
3
4
5
Effect on Livestock Wellbeing Death rate Tephra
E
if no evac. Thickness
None
0
0 mm
0
Pasture covered but rapidly (hours to Nuisance only
days) washes or falls off
Pasture covered but should eventually Risk of poisoning. Supp. feed
clear supplementary feed required required for 2 weeks
for days to weeks
Pasture smothered, 3 month recovery Starvation if no supp. feed.
High risk of poisoning
Pasture smothered, rehab of pasture Starvation if no supp. feed.
required (>3-6 month recovery)
High risk of poisoning
Pasture smothered, rehab of pasture Starvation if no supp. feed.
required (>12 month recovery)
0
>1 mm
0
0% >10 mm 0.00
1
25% >50 mm 0.25
50% >100 mm
0.5
100% >300 mm
1
Exposure Cells

12 cells around the volcano
Each cell has 25,000 dairy cows on 100 farms
Must be either evacuated or not

Additional Vulnerability:


 Southern
 >10
Cells (9 – 12) are vulnerable to loss of water
mm of ash on southern flanks of volcano will close WTP
 Death to cows within 5 days
1
2
3
4
6
5
10
7
9
12
25 km
8
11
Based on: Hurst, T. & Smith, W. (2010)
Volcanic ashfall in New Zealand –
probabilistic hazard modelling for multiple
sources, New Zealand Journal of Geology
and Geophysics, 53:1, 1-14
25 km
128mm/10,000 years
Northwest
West
North
25
20
15
10
5
0
Northeast
East
96mm/10,000 years
Southwest
South
64mm/10,000 years
Southeast
GeoNet: Probability of Eruption
simple(!) expert elicitation
Week
Eruption Size
Probability of
an eruption in
the next 7 days
Probability of an
eruption in the
next 30 days
1
Probability of an
eruption in the
next 90 days
Large Eruption (VEI 5)
0.10%
1%
1%
2
Large Eruption (VEI 5)
2%
5%
8%
3
Large Eruption (VEI 5)
10%
15%
20%
1
50 mm
2
3
100 mm
4
200 mm
300 mm
6
5
10
7
9
12
8
11
Northwest
West
North
25
20
15
10
5
0
Northeast
East
25 km
Southwest
Southeast
South
64mm/10,000 years
1
96mm/10,000 years
2
3
4
128mm/10,000 years
6
5
25 km
10
7
9
12
8
11
Northwest
West
North
25
20
15
10
5
0
Southwest
Northeast
East
Southeast
South
Evacuation constraints/rules


It will take 30 days to evacuate one cell
Taranaki farmers only have 5-10 days worth of
supplementary feed available (hard winter & start
of spring)
Value of your cows (V)


Presently, a dairy cow = $1,500 ea
But is this their true worth?
 Taranaki
dairy cow produces ~334kg/year milk solids
 Milk solids price ~$7/kg
 Cow production per year: $2,338
 Cow milking life of 8 years: $18,700
 This
is used as the equivalent of annual GDP/capita for humans

Key variables
 What
way does the ash blow?
 How much do we value our livestock?

Limitations/frustations of this semiquantitative/qualitative approach highlight the
value of a fully quantitative approach


Doesn’t consider the expense of maintaining cows in
receiving farms
Moving lactating cows
Stress = health problems
 Reduce or cease lactation = loss remaining season’s income



Map from Sandri et al. (2012) showing short-term P
of base surge and CBA-determined evacuation
zones (magenta) in AVF for Exercise Ruamoko
March 13.
Map from Marzocchi and Woo showing a Booleanlogic representation of a CBA-determined
evacuation zone for Campi Flegrei Caldera, Italy
50 mm
100 mm
200 mm
300 mm
Modeled Isopachs from
5700 BP Inglewood
eruption
Exercise Ruaumoko, media inject 12 March 2008
Jan Lindsay
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
transportation:
and
20
100
80
20
40
5 most
20 common
30
15
10
150
40
35
Ash hazard Duration of
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
timeyears
consuming
ash
15 years 15 years 15
years and
15 years
1-2 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
SEVERITY
No
No
No
No
No
Few isolated issues
<50% <50% <30% <25% >75% <5% 100% >50% <5% <5% <20% <5% <20%
Widespread outages
design
key
<50% Yes
Yes
Yes >75% Yes >50% System
---- factor
???
--Total disruption
Yes
General findings for infrastructure

Disruptive rather than catastrophically damaging

Most infrastructure systems will tolerate volcanic ash...up to a point

Loose relationship with ash thickness/load, but strongly influenced by:




system design
level of planning
adaptive capacity
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
Evacuations




Official evacuations rare
Airborne ash
= anxiety of
respirable
hazard
Anxiety of ash
contamination of
water supplies
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
Summary 1: Thresholds


Evidence supports the view of ‘cities’
as complex self organising systems
(e.g. Alesch & Siembieda 2012)
Hypothesis of establishing a critical
threshold of ash hazard intensity for
common levels of disruption across
city is probably null
 But
we can use it as a guide
Summary 2 – Thresholds?
Ash
Thickness
Urban Infrastructure Systems
Evacuation considerations
1 mm
Mostly nuisance
Public health concerns
10 mm
Some limited impacts to infra.
systems. Depends on system design
Some self evacuation.
75 mm
Widespread disruption to infra.
systems.
Self evacuations likely, may extend up
to months depending on ‘ashy’
conditions & residual functionality
400 mm
Not observed – but likely to result
in widespread disruption and
damage to systems
Livelihoods compromised  long term
evacuation likely.

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)