La gestione del tempo nella prevenzione dei rischi naturali

Paolo Gasparini
Dipartimento di Scienze Fisiche
Università di Napoli “Federico II”
CRdC – AMRA
Le tecnologie
dell’allarme precoce
e la gestione
dei rischi naturali
“Le tecnologie dell’allarme precoce e la
gestione dei rischi naturali”
“La gestione del tempo nella prevenzione dei rischi naturali”
Venerdì 28 Novembre 2003
Institut français de Naples “Le Grenoble”
Le tecnologie
dell’allarme precoce
e la gestione
dei rischi naturali
EARLY WARNING
All the actions which can be
carried out during the lead time
of a catastrophic event in order
to mitigate its effects.
Le tecnologie
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LEAD TIME
The time elapsing from the moment
when the occurrence of a catastrophic
event is reasonably certain till the
moment the event really occurs.
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Event Source
Considered area
Propagation Path
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TYPICAL LEAD TIMES
MOST SIGNIFICANT ACTIONS
EARTHQUAKES: seconds to tens of seconds
AUTOMATIC
TSUNAMIS: minutes to hours
ALERT + INFORMATION
METEROLOGICAL EVENTS: hours to days
ALERT + INFORMATION
FLOODS AND LANDSLIDES: hours to days
COPING CAPACITY
VOLCANIC ERUPTIONS: hours to weeks
COPING CAPACITY
SEISMIC EARLY WARNING
CHRONOLOGY
1855: Palmieri seismograph
1868: The Concept of an early warning system was proposed by J.D. Cooper for San Francisco.
1880 Milne seismograph
1885 Theory of Rayleigh surface waves
1899 Oldham and Wiechert identify P and S waves as elastic waves
1910 Reid elastic rebound theory for the 1906 San Francisco earthquake
1911 Theory and identification of Love surface waves
1935 Richter Magnnitude scale
1965: Japan national railways installed an instrumental early warning system to
protect the Tohoku Shinkansen line (threshold at PGA = 0.04 g at 5 Hz)
1982: Implementation of the improved UrEDAS system (detection of P-waves) to
protect the Tokado Shinkansen line and since 1992 in California (1994 Northridge earthquake)
1992: Implementation of Seismic Alert System for Mexico City
1994: CUBE and REDI seismic warning systems in Southern and Northern California
1996: Implementation of the Taiwan Rapid Earthquake Information System
Le tecnologie
dell’allarme precoce
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Le tecnologie
dell’allarme precoce
e la gestione
dei rischi naturali
SYSTEMS IN PROGRESS
-
TRINET Project in Southern California
-
Feasibility study for Istanbul
-
Feasibility study for Bucharest
-
Feasibility study for Armenia
Le tecnologie
dell’allarme precoce
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Le tecnologie
dell’allarme precoce
e la gestione
dei rischi naturali
TYPICAL LEAD TIMES
Japan Shinkansen lines = 0 to 10 s
Mexico City = 65 - 72 s
Taiwan = tens of s
Istanbul = 0 to 70 s
Bucharest = 25 s
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PUBLIC WARNING
Schools - Media
Business centres - Hospital
INDUSTRY
TRASPORTATION
Sensitive industries - Life lines
Bridges – metro
Computer facilities - High tech industry
Trains - Aeroplanes
Emergency services
Disaster Management
Relief Organisations
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SEISMIC EARLY WARNING
INSTRUMENTS
Seismic network to detect the signals;
- Data processing system to identify
location and magnitude of the
earthquake;
- Warning information transmitter;
- Warning information receiver and processor;
- Automatic system.
Le tecnologie
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Le tecnologie
dell’allarme precoce
e la gestione
dei rischi naturali
Japan:
Protecting Bullet Trains
I. Alarm seismometers
• installed along all rail tracks
• shut off power when horizontal
acceleration exceeds a threshold
Front detection: deployed along coast
 gives ~15 sec warning
II. UrEDAS
• event parameters determined from
the P-arrival
Japan: Protecting Bullet Trains
II. UrEDAS
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…switching to event parameter determination from the P-arrival
1.
2.
3.
4.
Trigger on P-arrivals
Use predominant period in first 3 seconds to determine magnitude
Knowing the magnitude and amplitude, epicentral distance is estimated
Azimuth of P-arrival and epicentral distance gives event location
 At P-arrival + 3 sec have an estimate of event location and magnitude
5. S minus P time used to improve the epicentral distance estimate
Le tecnologie
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Seismic Alert System: Mexico City
“Front detection”
•
developed in 1989 in the wake
of the 1985 Michoacan
earthquake
•
12 stations along coast
•
station data transmitted to
central processing in Mexico
City
•
warning issued when two
stations indicate an event
greater than magnitude 5
•
~300 km allows ~60 sec
warning
300 km
Le tecnologie
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Le tecnologie
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e la gestione
dei rischi naturali
Guerrero earthquake
September 14, 1995
• magnitude 7.3
• event successfully
detected and an alert
issued
• 72 sec warning
• no real damage in
Mexico City
Taiwan:
Earthquake early warning
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Use classical network processing
approach:
• P-arrival used for event
detection and conformation
• S-arrival needed for magnitude
determination
 use sub-nets to reduce
wait time (circles on map)
System processing time:
20-30 seconds
Wu and Teng, 2002
Chi-Chi earthquake:
warning times
Le tecnologie
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- September 20, 1999
- magnitude 7.6
- 2,456 casualties
Example of how the system
would have worked for this
event:
Warning issued after 22 sec
Useful for regions more than
75km from epicenter
Triangles represent
population distribution
Wu and Teng, in press
1. Seismic infrastructure
TriNet
135 available
stations with:
• broadband and
strong motion
sensors
• capable of on-site
processing
• parameter transit
times < 1sec
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Earthquake alarm system
ElarmS timeline
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Summary:
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ElarmS capabilities
We are currently testing ElarmS, it will:
• provide 0 to 2 seconds warning of peak ground motion to
people directly above the earthquake epicenter
• provide approx. 10 seconds warning to people 30 km from
the epicenter
The certainty of the predicted ground motion
increases as the warning time decrease.
• users must decide their uncertainty tolerance
and their sensitivity to warning time
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ISTANBUL
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Potential Sources for Earthquakes larger than M 5.5 in Italy
Integrated Seismogenic Source dataset and Tectonic Lineaments
CRdC-AMRA
MULTICOMPONENT SEISMIC NETWORK
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Accelerometers and high frequency seism
Accelerometers and broad band seism
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Lion’s Gate Bridge
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Rete Nazionale dei Gasdotti
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Ignalina nuclear power plant
(Lithuania)