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Earthquake engineering and real-time early warning: the AMRA perspective. Iunio Iervolino* and Gaetano Manfredi *Assistant Professor of Structural Engineering.

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Presentation on theme: "Earthquake engineering and real-time early warning: the AMRA perspective. Iunio Iervolino* and Gaetano Manfredi *Assistant Professor of Structural Engineering."— Presentation transcript:

1 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

2 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Regional Earthquake Early Warning Systems and the ISNet Irpinia Seismic Network (Italy) Commonly used to give distributed estimates of the ground motion right after the event: SHAKEMAPS.

3 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Source-to-site distance Seismic network Ground motion at the site IM (i.e. PGA) Structural/non-structural performance/loss EDP (i.e. Maximum Interstory Drift Ratio) Epicenter Signal at the network stations Site-Specific Warning by Regional Networks: Hybrid EEWS BECAUSE OF REAL-TIME SEISMOLOGY!

4 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 RTS: Rapid estimation of event magnitude MTMT 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

5 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 RTS: Rapid estimation of event location 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 Triggered Stations Epicenter

6 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 PDF of magnitude conditional on the measures of the seismic instruments PDF of distance due to rapid localization method Ordinary Attenuation relationship Distribution of PGA at the site conditional on the measures of the seismic instruments Real-Time Probabilistic Hazard Analysis (RTPSHA) for Hybrid EEWS Negligible uncertainty Iervolino et al., Convertito et al., 2008.

7 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Magnitudes distribution Gutenberg-Richter Magnitude Measurements [s] The mean of the tau network measurements is all we need to estimate the magnitude! Iervolino et al., 2007.

8 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June stations t = 6s 23 stations t = 9s 28 stations t = 11s 30 stations t = 12s M=6 R=110km Event Simulation 2 stations t = 5s

9 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June stazioni25 stazioni 27 stazioni 4 stazioni 1 stazione Simulazione Hazard M=6; R=110km

10 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Real-Time Probabilistic Seismic Hazard Analysis (RTPSHA) - Summary Naples Estimation of Distance Estimation of PGA at the site Estimation of Magnitude

11 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Is the Bayesian estimator appropriate also if it tends to underestimate the magnitude? Iervolino et al., 2009.

12 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 False and Missed Alarm Probabilities Iervolino et al., 2006.

13 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 PGAc Pc ALARM ! Because the probability that PGA exceeds the limit value is too high When to activate security measures? Decisional Rules

14 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Estimation of PGA at the site Time-Dependent Uncertainty in Early Warning Iervolino et al., 2009.

15 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Estimation of PGA at the site Which uncertainty really matters in prediction of engineering ground motion parameters? Iervolino et al., 2009.

16 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Design Targets False Alarm Probability Lead Time Performances/ Consequences Low Perception Impact(e.g. Elevator) Low Perception Impact (e.g. Elevator) Medium Perception Impact (e.g.Trasportation Interruption High Perception Impact (e.g. Lifelines Interruption )

17 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 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

18 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 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.

19 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Application of RTPSHA on our school of engineering

20 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Event Detection Structure Specific Alert Regional alert Map Real-Time estimation of Magnitude and Location Developed with the group of Aldo Zollo Operating since July ID: utente PW: ergohttp:// :5800/

21 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Event detected on 19/11/2008 – 8.17 PM

22 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 A school classrom equipped with an EEWS terminal: how to set the alarm threshold Lets 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.

23 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 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!

24 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 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 Expected Loss 1. Loss probability depending on the alarming decision 2. Structural damage probability depending on buildings seismic response 3. Seismic response probability depending on hazard 4. Real-time hazard analysis Iervolino et al., 2009.

25 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June Loss functions No alarm loss Alarm loss (reduced because of security action) No shelteringSheltering of students under desks

26 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Expected loss as a function of the seismic instruments measures Expected Loss [] [s] No alarm Alarm Optimal Alarm threshold Iervolino et al., 2009.

27 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Early Warning and Structural Control Passive Control: to modify, the stiffnes and/orthe 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.

28 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 This model may be used to study other systems… A structure equipped with a semi-active control device activable by the EEWS: feasibility.

29 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 PASSIVE DEVICE Variable-Orifice Viscous Dampers

30 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Real-Time performance analysis 3. Seismic response probability depending on hazard 4. Real-time hazard analysis Expected Structural performance Iervolino et al., 2009b.

31 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Benefit of The EEWS in terms of reduction of Drift Response Iervolino et al., 2009b.

32 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Benefit of The EEWS in terms of reduction of Peak Floor Acceleration Iervolino et al., 2009b.

33 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Response improvement in respect to the structure without the EEWS

34 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 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;

35 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 References 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: /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.

36 Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP3 perspective. 1 st year: Real-Time Risk Analysis2 nd year: Engineering Issues3 rd year: Structural Applications SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 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.


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