2009 AGU Fall Meeting S33D. Research and Development in Nuclear Explosion Monitoring II Implementation of tsunami early warning using earthquake rupture

2009 AGU Fall MeetingS33D. Research and Development in Nuclear Explosion Monitoring II

Implementation of tsunami early warning

using earthquake rupture duration

Implementation of tsunami early warning

using earthquake rupture duration

Michelini A.1 and Lomax, A.2

1.Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy, [email protected] 2. ALomax Scientific, Mouans-Sartoux, France. [email protected]

Michelini A.1 and Lomax, A.2

1.Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy, [email protected] 2. ALomax Scientific, Mouans-Sartoux, France. [email protected]

http://s3.rm.ingv.it/D-E.php









Talk StructureTalk Structure

Problem and earlier work Duration-Exceedance Alarm design and implementation

Data Examples movie of tsunami (and non-tsunami) alerts

Summary

Problem and earlier work Duration-Exceedance Alarm design and implementation

Data Examples movie of tsunami (and non-tsunami) alerts

Summary


Problem and earlier work

Problem and earlier work Rapid tsunami assessment are critical for rapid alerts

and intervention. P-waves can provide very first information on earthquake

size and tsunami potential Tsunami Warning centers, depending whether local or

regional, rely on earthquake location and magnitude and on pre-determined tsunami scenarios for early warning Effective regional warning requires assessment in < 15’

Mwp (Tsuboi et al., 1995) is the quickest methodology at teleseismic distances to determine earthquake size but Accurate up to Mw~7.5 Underestimates Mw>7.5 and tsunami earthquakes because it does not account for long duration ruptures (i.e., later pulses on the waveforms indicative of source duration)

Rapid tsunami assessment are critical for rapid alerts and intervention.

P-waves can provide very first information on earthquake size and tsunami potential

Tsunami Warning centers, depending whether local or regional, rely on earthquake location and magnitude and on pre-determined tsunami scenarios for early warning Effective regional warning requires assessment in < 15’

Mwp (Tsuboi et al., 1995) is the quickest methodology at teleseismic distances to determine earthquake size but Accurate up to Mw~7.5 Underestimates Mw>7.5 and tsunami earthquakes because it does not account for long duration ruptures (i.e., later pulses on the waveforms indicative of source duration)


Problem and earlier work (2)


Duration Magnitudes (e.g., MED, Mwpd, mBc, Mhara) take into account the source duration explicitly, are calibrated against MW

CMT and do not saturate

Theta (i.e., energy to moment ratio) proposed as indicator of tsunami earthquakes (Newman and Okal, 1998)

P-wave duration, To, alone appears to be a reliable indicator of tsunami genesis (Lomax and Michelini, 2009a,b; Bormann and Saul, 2009)

Duration Magnitudes (e.g., MED, Mwpd, mBc, Mhara) take into account the source duration explicitly, are calibrated against MW

CMT and do not saturate

Theta (i.e., energy to moment ratio) proposed as indicator of tsunami earthquakes (Newman and Okal, 1998)

P-wave duration, To, alone appears to be a reliable indicator of tsunami genesis (Lomax and Michelini, 2009a,b; Bormann and Saul, 2009)


raw, velocity seismogram

1.5 Hz, Gaussian-filtered seismogram

ground-displacement seismogram

T0 estimate: smoothed, velocity-squared envelope

M0 estimate: integral of displacement over duration T

0

(Mwpd=8.5)

Duration-amplitude processing steps:12 September 2007,M8.4 Sumatra

Du

rati

onD

ura

tion

Am

plit

ud

e

T0


Tsunamigenic earthquakes: rupture duration To > 50s

(To versus Mw discriminant)

Tsunamigenic earthquakes: rupture duration To > 50s

(To versus Mw discriminant)


Tsunami Early Warningusing Duration - Exceedance

Tsunami Early Warningusing Duration - Exceedance

(from Lomax & Michelini, 2009b; http://s3.rm.ingv.it/D-E.php

2006, Mw7.7,

T0=180s, I

t=18

Indonesia tsunami earthquake

2009, Mw7.6,

T0=39 s, I

t=1

Tonga Islands


Discrimination of tsunamigenic earthquakes

Discrimination of tsunamigenic earthquakes


IMS auxiliary seismic network



IMS primary seismic network

IMS primary seismic network


IRIS SeedLink-realtime station subset

IRIS SeedLink-realtime station subset


QuickTime™ and aYUV420 codec decompressor

are needed to see this picture.

D-E for September 29, 2009 Mw=8.2 Samoa

D-E for September 29, 2009 Mw=8.2 Samoa


QuickTime™ and aYUV420 codec decompressor

are needed to see this picture.

D-E for September 30, 2009 Mw=7.7

Sumatra

D-E for September 30, 2009 Mw=7.7

Sumatra


SummarySummary Tsunami warning should rely on different tools in order to issue alerts

Real time data at global scale such as those provided through the SeedLink protocol implemented at IRIS can be used for dedicated tsunami warning procedures

Duration-Exceedance, D-E, can be used as fast and reliable discriminant of tsunami occurrence

D-E is visualized in real-time on the INGV seismic center video-wall and the procedure is available at http://s3.rm.ingv.it/D-E.php

Tsunami warning should rely on different tools in order to issue alerts

Real time data at global scale such as those provided through the SeedLink protocol implemented at IRIS can be used for dedicated tsunami warning procedures

Duration-Exceedance, D-E, can be used as fast and reliable discriminant of tsunami occurrence

D-E is visualized in real-time on the INGV seismic center video-wall and the procedure is available at http://s3.rm.ingv.it/D-E.php














AcknowledgementsAcknowledgements

This work has been funded by the Italian Civil Protection (project INGV-DPC 2007-2009 S3 contract)

The data have been obtained from IRIS accessing the realtime DMC SeedLink server

The plots are made with GMT (http://gmt.soest.hawaii.edu).

This work has been funded by the Italian Civil Protection (project INGV-DPC 2007-2009 S3 contract)

The data have been obtained from IRIS accessing the realtime DMC SeedLink server

The plots are made with GMT (http://gmt.soest.hawaii.edu).





Earliest tsunami warnings: Primarily Magnitude (Mwp) at US tsunami centers (PTWC and WCATWC; T ~ 5-10’)

JMA/Japan warnings based on Magnitude and predetermined scenarios (T ≤ 3’)

GITEWS/German-Indonesian based on magnitudes (e.g., mB, mBc) alone ( T≤ 5’)

Australian Tsunami Warning System based on magnitude (T ≤ 15’)

Earliest tsunami warnings: Primarily Magnitude (Mwp) at US tsunami centers (PTWC and WCATWC; T ~ 5-10’)

JMA/Japan warnings based on Magnitude and predetermined scenarios (T ≤ 3’)

GITEWS/German-Indonesian based on magnitudes (e.g., mB, mBc) alone ( T≤ 5’)

Australian Tsunami Warning System based on magnitude (T ≤ 15’)


To versus Mw discriminantTo versus Mw discriminant


The duration-amplitude procedure produces rapidly an earthquake moment magnitude Mwpd from P-wave recordings at teleseismic distances (30-90º)

Mwpd available within < 20 minutes after OT. For large earthquakes Mwpd (with moment scaling) matches MwCMT typically within ±0.2 magnitude units.

Mwpd does not exhibit saturation for the largest events.

Mwpd equals or is better than other procedures for rapid moment magnitude determination.

Duration, T0, seems to be a robust indicator for tsunamigenic earthquakes (i.e., T0 ≥ 50 s)

The Duration-Exceedance proxy to T0, produces rapid estimates (5-10 minutes) for tsunamigenic earthquakes

From Lomax and Michelini, 2009a





It - Tsunami importance based on water height, h, and 0-4 descriptive indices, i, of tsunami effects (deaths, injuries, damage, houses destroyed)

(NOAA/WDC Historical Tsunami Database (NGDC, 2008)

€

I t = h + ideaths + iinjuries + idamage + ihousesdestroyed

Tsunami importance, It, and Duration, T0, for identification of tsunami earthquakes

From Lomax and Michelini, GJI, 2009a

Documents

2009 AGU Fall Meeting S33D. Research and Development in Nuclear Explosion Monitoring II Implementation of tsunami early warning using earthquake rupture