EGU General Assembly
EGU2010-10413
Emergency preparedness: communitybased short-term eruption forecasting at
Campi Flegrei
J. Selva, W. Marzocchi, P. Papale, L. Civetta, E. del Pezzo
INGV-DPC Project UNREST
Vienna, 05/05/2010
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
Emergency Preparedness
definition in advance of tools to assist decision makers
Short-term eruption forecasting keys:
1.
to recognize anomalous signals and relate them to
physical processes
 ELICITATIONS
2.
to assign probability values
 STATISTICAL MODEL
3.
to quickly provide answers to unexpected phenomena
 TRAINED COMMUNITY
 ONLINE TOOLS
Vienna, 05/05/2010
RESULTS
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
RESULTS
VOLCANOLOGICAL KNOWLEDGE
different interpretations
different expertise
big community
+
STATISTICAL MODELS
expert on volcanic process
≠
expert in statistics
=
INDERECT ELICITATIONS
the community of experts set the
parameters of the statistical model
STATISTICAL MODEL
VOLC. COMMUNITY
FORECASTING TOOL
FORECASTING TOOL
must be community based
must be quickly reviewable
Vienna, 05/05/2010
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
Statistical model: Bayesian Event Tree
for Eruption Forecasting (BET_EF)
Vienna, 05/05/2010
RESULTS
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
RESULTS
UNREST
MAGMATIC
UNREST
ERUPTION
VENT
LOCATION
ERUPTION
SIZE
NODE 1
NODE 2
NODE 3
NODE 4
NODE 5
unrest
no unrest
magma
no magma
eruption
no eruption
loc #1
loc #2
…
loc #700
lava dome
small expl.
medium expl.
large expl.
NODE 1-2-3
- identification of anomalies indicating each “event” (node)
- definition of the “state of anomaly” through thresholds
 evaluation of the probability at node from the
“state of anomaly” of all informative parameters
Vienna, 05/05/2010
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
PARAMETERS
THRESHOLD 1
Anomaly:
THRESHOLD 2
z
Information:
z
M
O
D
E
L
Probability:
1 - e-S{w z}
BACKGROUN
D
Gray Area
ANOMALY
measure
Vienna, 05/05/2010
RESULTS
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
Volcanological interpretation: setting
BET_EF through repeated elicitations
Vienna, 05/05/2010
RESULTS
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
DELPHI METHOD
structured process for collecting and distilling knowledge from a
group of experts, facilitating the formation of a group judgement:
• structured information flows
• feedback of participants
• anonymity of participants
EXPERT GROUP
• 30 researchers within 2 projects from 2005
• 5 elicitations sessions
• scores of experts reflecting their consideration within the group
• consensus is formed during general discussions
GOAL: AGREED GROUP OPINION
• pre-eruptive node and tools
• group of experts trained to ET and elicitation procedures
Vienna, 05/05/2010
RESULTS
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
RESULTS
COMMUNITY-FORMING PROCESS
Pre-elicitation meetings (seminars, meetings, internet forum):
statistical model, tools for the elicitation, discussions on the monitoring network, studies/models
(cross-feedback), interpretations (consensus-seeking)
Elicitation sessions: physical meetings --> internet session
score the other experts, selection of parameters and thresholds
Post-elicitation meetings (moderated discussions sessions):
consequence of choices and performance of the model, general discussions on single parameters,
measures and definitions, etc.
Vienna, 05/05/2010
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
RESULTS
ONLINE ELICITATION – http://bet.bo.ingv.it/elicitazione/elicitations.html
DURING ELICITATION
- Predefined lists of experts and parameters
- Online forms to
-selected parameters
-assign thresholds
-vote the other experts
- Online forum
ANALYSIS OF THE RESULTS
- Automatic analysis
- Stability check through differentiated
statistical analyses
- Automatic publication of results
Vienna, 05/05/2010
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
Results for Campi Flegrei
(project INGV-DPC UNREST)
Vienna, 05/05/2010
RESULTS
Index:
Emergency preparedness at Campi Flegrei
BACKGROUN
D
ELICITATION V
VT (M > 0.8)
LP/VLP/ULP
Rate uplift
Uplift
T Pisciarelli
VLP/ULP
Deep VT (M > 0.8)
Deep LP (> 2 Km)
Disp. Hypocenters
Tremor
Deep Tremor (>3.5
Km)
Acc. seismic events
Acc. RSAM
New fractures
Macr. (dm)
variation in def.
Migr. max uplift
Ext degassing
Magm. comp. gases
HF - HCl - SO2
Phreatic activity
Gray
area
[ev/day]
5
15
2
10
0.7
1.3
2
100
6
110
[ev/day]
[ev/day]
BET_EF
Gray
area
UNREST
[ev/month
]
[cm/month
]
[cm]
INTRO
ELICITATIONS
MAGM.
UNREST
6
15
1
2
3
5
20
20
Gray
area
1
[Km]
RESULTS
YES
ERUPTION
3
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
LEGENDA:
YES
YES
YES
Boolean parameters are represented by “YES”
“Gray areas” correspond to variable probability of
being in the adjacent states, depending on the
measured values
Vienna, 05/05/2010
YES
YES
Index:
Emergency preparedness at Campi Flegrei
INTRO
BET_EF
BOOLEAN
QUANTITATIVE
To UNREST
3 (0.40)
5 (0.60)
To MAGMATIC UN.
6 (0.60)
4 (0.40)
To ERUPTION
8 (0.90)
1 (0.10)
ELICITATIONS
RESULTS
SEISMICITY
DEFORMATION
GASES
To UNREST
2 (0.25)
3 (0.37)
3 (0.37)
To MAGMATIC UN.
5 (0.50)
3 (0.30)
2 (0.20)
To ERUPTION
4 (0.45)
3 (0.33)
2 (0.22)
Vienna, 05/05/2010
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
SEISMICITY
To UNREST
counting VT, LP/VLP/ULP
basic observations
To MAGMATIC UN.
deep VT, deep LP
tremor
depth, wave forms
To ERUPTION
acceleration
dispersion hypocenters
macroscopic variations
Vienna, 05/05/2010
RESULTS
Index:
Emergency preparedness at Campi Flegrei
INTRO
BET_EF
ELICITATIONS
DEFORMATION
To UNREST
uplift, uplift rate
Less sensitive:
To MAGMATIC UN.
uplift
Too many interpretations
heard?
To ERUPTION
surf. fractures
macroscopi variations
migr. of maximum uplift
macroscopic variations
Vienna, 05/05/2010
RESULTS
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
GASES
To UNREST
T fumarole
Ext. degassing struct.
No chemistry: delayed
response of gases
To MAGMATIC UN.
Acidic gas
Magm. component
 directly into eruption
Smaller changes
controlled by hydroth.
system
To ERUPTION
Acidic gas
Phreatic explosions
macroscopic variations
Vienna, 05/05/2010
RESULTS
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
Seismicity:
Highest sensitivity
Deformation:
Macroscopic changes
Gases:
Macroscopic changes
RESULTS
In Favour of Seismicity:
Longest sesmic record and experience, exceptional sequence largely
documented in 1982-84, more developed network, rapidity of information,
effective higher sensitivity, …
Against Deformation and Gases:
Interpretations too model-dependent, many contrasting interpretations, large
control of hydrothermal system, delayed gas-related signals, …
Vienna, 05/05/2010
Emergency preparedness at Campi Flegrei
Index:
INTRO
BET_EF
ELICITATIONS
SUMMARY
• Statistical model (BET_EF) and volcanological interpretation are kept separated:
• separate validations are possible
• experts asked for volcanological interpretation only
• an automatic and easily reviewable tool for eruption forecasting is set
• The 5 yrs long elicitation process provided
• a global picture of the confidence on the various volc. interpretations
• clues to guide future implementations in the monitoring network and
research investments
• trained a community of experts to quickly answer to crises
Vienna, 05/05/2010
RESULTS