Earthquake engineering and real-time early warning the AMRA

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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd year: Structural Applications 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. SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009

Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd year: Structural Applications Real-Time Probabilistic Hazard Analysis (RTPSHA) for Hybrid EEWS 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 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.

Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd year: Structural Applications Magnitude’s distribution Iervolino et al. , 2007. Measurements Gutenberg-Richter [s] The mean of the tau network measurements is all we need to estimate the magnitude! Magnitude SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Magnitude

1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd year: Structural Applications Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP 3 perspective. M=6 R=110 km Event Simulation t = 5 s 6 s 11 s 9 s 12 s SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 30 stations 28 23 stations 2 8

Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd year: Structural Applications Simulazione Hazard M=6; R=110 km 11 stazione 254 stazioni 1 27 stazioni SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009

Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd year: Structural Applications False and Missed Alarm Probabilities SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009 Iervolino et al. , 2006.

Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd year: Structural Applications When to activate security measures? Decisional Rules ALARM ! Because the probability that PGA exceeds the limit value is too high Pc PGAc SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009

Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd year: Structural Applications Event detected on 19/11/2008 – 8. 17 PM SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009

Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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. SAFER Project Final Meeting – Potsdam, 3 – 5 June 2009

Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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 Expected Loss 1. Loss probability 2. Structural damage 3. Seismic response depending on the probability depending onprobability depending alarming decision 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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)

2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis Alarm [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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd year: Structural Applications Early Warning and Structural Control ü Passive Control: to modify, the stiffnes and/or the damping so as to achieve a better structural response; ü Semi-Active Control: to modify just-in-time the dynamic characteristics of the structure as to achieve the optimal response; ü 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd year: Structural Applications Real-Time performance analysis 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. , 2009 b.

Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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. , 2009 b.

Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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. , 2009 b.

Iunio Iervolino – Structural engineering and real-time early warning: the SAFER-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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. 1029/2008 GL 036644, 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-WP 3 perspective. 1 st year: Real-Time Risk Analysis 2 nd year: Engineering Issues 3 rd 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