Earthquake engineering and real-time
early warning: the AMRA perspective.
Iunio Iervolino* and Gaetano Manfredi
*Assistant Professor of Structural Engineering
Department of Structural Engineering, University of Naples Federico II, Italy.
SAFER Project Final Meeting – Potsdam 3-5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Regional Earthquake Early Warning Systems
and the ISNet Irpinia Seismic Network (Italy)
0
25
50 km
Benevento
Caserta
Avellino
Napoli
Potenza
Salerno
1981 – 2002 Seismicity
INGV Seismic Catalogue
Earthquake M>3
Earthquake M<3
1980 Earthquake Ms 6.9
Seismogenetic faults of 1980 Earthquake
Current Seismic Network
Seismic network under construction (2006)
Main City
Urbanized area
Commonly used to give distributed estimates of the ground motion right after the
event: SHAKEMAPS.
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Site-Specific Warning by Regional Networks:
Hybrid EEWS
Structural/non-structural
performance/loss
Seismic
network
EDP (i.e. Maximum
Interstory Drift Ratio)
IM (i.e. PGA)
Epicenter
Source-to-site
distance
Ground
motion at
the site
Signal at the
network
stations
BECAUSE OF REAL-TIME SEISMOLOGY!
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
RTS: Rapid estimation of event magnitude
MT
Seismologists (i.e. Allen & Kanamori, 2003) claim it is possible to estimate the magnitude from
the predominant period () of the first 4 sec of the P-wave velocity recording
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
RTS: Rapid estimation of event location
Epicenter
Triggered
Stations
Other seismologists (i.e. Zollo et al., 2007) claim it is possible to locate the hypocenter with
negligible uncertainty within 4 sec from the event origin time
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Real-Time Probabilistic Hazard Analysis
(RTPSHA) for Hybrid EEWS
PDF of distance due
to rapid localization
method
Ordinary
Attenuation
relationship
f  PGA |   
  f  PGA | m, r  f
M |1 , 2 ,..., 
 m |   f R|s , s ,..., s  r | s  dr dm
1
2

M R
Distribution of PGA at
the site conditional on
the measures of the
seismic instruments
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
PDF of magnitude
conditional on the
measures of the
seismic instruments
Negligible
uncertainty
Iervolino et al., 2006.
Convertito et al., 2008.
2nd year: Engineering Issues
3rd year: Structural Applications
Magnitude’s distribution


 

2
2
 2 log   ln  τi   
 2
log  
log 



 i1




e
f m |  

M MAX



 

2
2
 2 log   ln  τi   
 2
log  
log 



 i1



e
Iervolino et al., 2007.
e  m

 f m |

e  m dm
M MIN
Gutenberg-Richter
Measurements
[s]
The mean of the tau network
measurements is all we need to estimate
the magnitude!
f(M)
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
3
Magnitude
SAFER Project Final Meeting
– Potsdam, 3 – 5 June 2009
3,5
4
4,5
5
5,5
6
M
Magnitude
6,5
7
7,5
8
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
M=6 R=110km Event Simulation
t = 5s
6s
9s
11s
12s
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
30
232
28
8 stations
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Simulazione Hazard M=6; R=110km
11
stazioni
25
41stazioni
stazione
27
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Real-Time Probabilistic Seismic Hazard Analysis
(RTPSHA) - Summary
Naples
Estimation
of Distance
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Estimation of
Magnitude
Estimation of
PGA at the site
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Is the Bayesian estimator appropriate also if it
tends to underestimate the magnitude?
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iervolino et al., 2009.
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
False and Missed Alarm Probabilities
MA : no Alarm  PGATrue  PGAC 

 FA :  Alarm  PGATrue  PGAC 
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iervolino et al., 2006.
2nd year: Engineering Issues
3rd year: Structural Applications
When to activate security measures?
Decisional Rules
SABETTA E PUGLIESE M=6 E R=120 km
1
0,9
Alarm if P [ PGA  PGAC ]  PC
0,8
0,7
P[PGA>PGAc]
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
0,6
0,5
ALARM ! Because the
probability that PGA exceeds
the limit value is too high
0,4
Pc
0,3
0,2
0,1
PGAc
0
0
0,1
0,2
0,3
0,4
2
PGA [m/s ]
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
0,5
0,6
0,7
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Time-Dependent Uncertainty in Early Warning
Estimation of
PGA at the site
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iervolino et al., 2009.
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Which uncertainty really matters in prediction
of engineering ground motion parameters?
Estimation of
PGA at the site
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iervolino et al., 2009.
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Design Targets
Lead Time
Medium Perception
Impact (e.g.Trasportation
Interruption
Low Perception
Impact (e.g.
Elevator)
High Perception
Impact (e.g. Lifelines
Interruption )
False Alarm
Probability
Performances/
Consequences
SAFER Project
Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Engineering Requirements of EEWS
• Quantitative real-time assessment of seismic
risk (losses for specific application)
• Time dependent decision making
(quantification of trade-off between lead-time
and costs of missed/false alarms)
• Automated decision for structural control
system
Consequence-based approach
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Lead-time maps for the case-study region can be superimposed to real-time
risk reduction actions for specific structural systems. These security
measures can be classified according to the time required to be carried out.
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Application of RTPSHA on our school of engineering
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Developed with the group of Aldo Zollo
Operating since July 25 2008 http://143.225.72.209:5800/ - ID: “utente” PW: “ergo”
Event Detection
Real-Time estimation of
Magnitude and Location
Regional alert Map
Structure Specific Alert
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Event detected on 19/11/2008 – 8.17 PM
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
2nd year: Engineering Issues
3rd year: Structural Applications
A school classrom equipped with an EEWS
terminal: how to set the alarm threshold
Let’s consider a simple school class equipped with a ringer and suppose that the
students are trained to shelter under the desks when the alarm is issued.
Desk
6m
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
Lighting
36 m2
7m
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
What causes loss?
a) Structural collapse (DS)
b) No structural damage, but collapse of lighting (NDS)
a) No structural damage, no lighting damage (loss due to
false alarm)
Total expectaion theorem: The total expected loss is the
summation of the expected losses corresonding to these
three cases!
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Real-Time loss assessment
Extending the hazard approach it is possible to determine the
expected losses condiotioned to the measurements of the seismic
network in the case of alarming or not
E L |    
 
l f  l d , g    f  d edp  f  edp pga  f  pga |   dL dD dEDP dPGA
L D EDP PGA
Expected
Loss
1. Loss probability
depending on the
alarming decision
2. Structural damage 3. Seismic response
probability depending probability depending
on building’s seismic
on hazard
response
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
4. Real-time
hazard analysis
Iervolino et al., 2009.
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
1. Loss functions
No sheltering
No alarm loss
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Sheltering of students
under desks
Alarm loss
(reduced because
of security action)
2nd year: Engineering Issues
3rd year: Structural Applications
Expected loss as a function of the seismic
instruments measures
No alarm
Expected Loss [€]
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
Alarm
τ̂
[s]
Optimal Alarm threshold
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iervolino et al., 2009.
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Early Warning and Structural Control
 Passive Control:
to modify, the stiffnes and/or the damping so as to achieve a
better structural response;
 Semi-Active Control:
to modify just-in-time the dynamic characteristics of
the structure as to achieve the optimal response;
 Active Control:
based on the availability of large force actuators able to
counterbalance inertial forces due to seismic excitation.
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
A structure equipped with a semi-active control
device activable by the EEWS: feasibility.
This model may be used to study other systems…
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Variable-Orifice Viscous Dampers
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
 PASSIVE DEVICE
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Real-Time performance analysis
ON if P[EDPuncontrolled  EDPc | ]  Pc
Device ON or OFF 
OFF if P[EDPuncontrolled  EDPc | ]  Pc
E  EDP   
  edp f  edp | pga  f  pga   dEDP dPGA
EPD PGA
Expected
Structural
performance
3. Seismic response
probability depending
on hazard
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
4. Real-time
hazard analysis
Iervolino et al., 2009b.
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Benefit of The EEWS in terms of reduction of
Drift Response
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iervolino et al., 2009b.
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Benefit of The EEWS in terms of reduction of
Peak Floor Acceleration
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iervolino et al., 2009b.
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Response improvement in respect to the
structure without the EEWS
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Design and Feasibility issues for the engineering
use of EEWS for structural “control”
• Maximization of the lead time is not the only design
target, in some case it is not even the principal
design objective;
• The uncertainties related to the real-time
estimations of earthquake features have to be
integrated with the models of seismic response of
facilities to protect;
• False and missed alarm probabilities have to be
optimized;
• The alarm thresholds have to be set on the basis of
expected losses;
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
References
http://www.saferprojct.net/publications
• Iervolino I., Giorgio M., Galasso C., Manfredi G. (2009) Uncertainty in early warning
predictions of engineering ground motion parameters: what really matters? Geophysical
Research Letters, DOI:10.1029/2008GL036644, in press.
• Convertito V., Iervolino I., Giorgio M., Manfredi G., Zollo A. (2008). Prediction of
response spectra via real-time earthquake measurements. Soil Dyn Earthquake Eng,
28: 492–505.
• Iervolino I., Convertito V., Giorgio M., Manfredi G., Zollo A. (2006). Real-time risk
analysis for hybrid earthquake early warning systems. Journal of
earthquake
Engineering, 10: 867–885.
• Iervolino I., Giorgio M., Manfredi G. (2007). Expected loss-based alarm threshold set for
earthquake early warning systems. Earthquake Engn Struct Dyn, 36: 1151–1168.
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009
Iunio Iervolino – Structural engineering and real-time
early warning: the SAFER-WP3 perspective.
1st year: Real-Time Risk Analysis
2nd year: Engineering Issues
3rd year: Structural Applications
Early Warning Special Issue
•
Tentative Title: Prospects and applications of earthquake early
warning, real-time risk management, rapid response and loss
mitigation;
•
Topics: Risk analysis, system performance evaluation and feasibility
studies, design of earthquake engineering applications of EEW, civil
protection via EEW;
•
SDEE Editor in chief: Mustafa Erdik; Guest editors: Iunio Iervolino and
Aldo Zollo;
•
Expected publication date: Jan 2010.
SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009