Tsunami early warning within 5 minutes... ...and true size of large earthquakes within 10 minutes Anthony Lomax ALomax Scientific, Mouans-Sartoux, France
Alberto Michelini Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy
1. Tsunami size, seafloor uplift and seismic moment 2. Tsunamigenic earthquakes: the Td∙T0, Td∙T50Ex discriminant 3. Mwpd – rapidly gives true size of large earthquakes 4. Examples: Tohoku 2011, Mentawai 2010 5. Conclusions
Tsunami size depends on seafloor uplift
→ tsunami → ocean displacement
→ seafloor uplift
earthquake rupture
Seafloor uplift not directly related to seismic moment
re 1 u t p ru
z moment M01 ≈ M02 “seismic” faulting model
p ru
e t ur
2
Seafloor uplift not directly related to seismic moment
loor f a e s re 1 u t p ru
z moment M01 ≈ M02 “seismic” faulting model
t uplif
if t l p ru o o fl sea
p ru
e t ur
2
Dominant period Td and apparent duration T0, T50Ex Tsunamigenic
P broadband
2006, Mw7.7
Td
P+60s
50s
Indonesia tsunami earthquake HF 1-5Hz
1 min
S
T 50Ex T50Ex
T0>>50s
Td – dominant period of early P-waves T0 – duration of high-frequency P-waves T50Ex – early estimate if T0 exceeds 50s
Dominant period Td and apparent duration T0, T50Ex Tsunamigenic
P broadband
2006, Mw7.7
Td
50s
Indonesia tsunami earthquake HF 1-5Hz
P+60s
S
T 50Ex T50Ex
T0>>50s
Non-Tsunamigenic
P
Td
P+60s
broadband
2009, Mw7.6
50s
Tonga Islands HF 1-5Hz
T50Ex
T0 TdT50Ex2 “tsunami” faulting model
t uplif
if t l p ru o o fl sea
p ru
e t ur
2
Tsunamigenic earthquakes: the Td∙T0 discriminant MwCMT → OT+20m+
7.5
So S
6.0
So
Mw=7.45
S
500
Missed 50 2
4
6
8 10 12 14 16 18 20
It
O
T B
T
B
So W? So U? U OUO? S U?UO?
B R So So
UO? UO?
0
B B T
T
S
7.0
T
T
So
0
“tsunami importance” 0-20 scale
TdT0=510s2 R So B So
OK
O U?So U? U
TTdTo d ∙T0
T
IT?
T
O
8.0
6.5
5000
73% OK
False
W?
OK
M MwCMT wCMT
8.5
IT?
67% OK
False
9.0
Td∙T0 discriminant → OT+5-10m
2
4
6
So
Missed
8 10 12 14 16 18 20
It
tsunami impact measures derived from: NOAA/WDC Historical Tsunami Database
Tsunamigenic earthquakes: the Td∙T0 discriminant MwCMT → OT+20m+
7.5
O
T B S O So T U? U? U So
7.0
TB
T
T
Mw=7.45
vs .A lin ea rT dT o
ea lin
o rM
TTdTo d ∙T0
MMwCMT wCMT
8.5
5000
t . A W? s v
IT?
t
IT?
9.0
8.0
Td∙T0 discriminant → OT+5-10m
S
T BT So O
T
T B
W?
500
U U? O U? So
R
TdT0=510s2 R
6.5 6.0 0.02
0.2
2
At (m)
20
50 0.02
tsunami amplitude at 100km
0.2
2
20
At (m)
tsunami amplitude measures derived from: NOAA/WDC Historical Tsunami Database
Mwpd – rapidly gives true size of large earthquakes 2007, Mw8.4 Sumatra
2 min
T0
P
S
HF 1-5Hz
Mwp
Mwpd
ground-displacement
M0 estimate: integral of displacement over duration T0
Mwpd OT+5-10min
X Not applicable in strong surface wave
coda from proceeding large earthquake.
S
Real-time simulation: Mw9.1, Tohoku, Japan 2011 OT+0min Devastating Devastating mega-quake mega-quakeand andtsunami, tsunami, Tsunami Tsunamiarrives arrivesat atcoast: coast:~OT+35min ~OT+35min Early-est Early-estrealtime realtimemonitor monitor early-est.rm.ingv.it early-est.rm.ingv.it
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw9.1, Tohoku, Japan 2011 OT+1min
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw9.1, Tohoku, Japan 2011 OT+2min
event eventlocated located
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw9.1, Tohoku, Japan 2011 OT+3min
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw9.1, Tohoku, Japan 2011 OT+4min
high high tsunami tsunami potential potential
high highmagnitudes magnitudes
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw9.1, Tohoku, Japan 2011 OT+5min
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw9.1, Tohoku, Japan 2011 OT+6min
very veryhigh high tsunami tsunami potential potential
TT0 164s 0 164s
MMwpd 9.2 wpd 9.2
focal focal mechanism mechanism
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw9.1, Tohoku, Japan 2011 OT+7min
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw9.1, Tohoku, Japan 2011 OT+8min
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw9.1, Tohoku, Japan 2011 OT+9min
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw9.1, Tohoku, Japan 2011 OT+10min
very veryhigh high tsunami tsunami potential potential
TT0 144s 0 144s
MMwpd 9.1 wpd 9.1
focal focal mechanism mechanism
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw7.8, Mentawai 2010
OT+0min
Locally Locallydevastating, devastating, slow, slow,“tsunami” “tsunami”earthquake, earthquake, Tsunami Tsunamiarrives arrivesat atcoasts: coasts:~OT+15-40min ~OT+15-40min
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw7.8, Mentawai 2010
high high tsunami tsunami potential potential
OT+4min
high highmagnitudes magnitudes
event eventlocated located
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw7.8, Mentawai 2010
high high tsunami tsunami potential potential
TT0 128s 0 128s
OT+7min
MMwpd 7.7 wpd 7.7
focal focal mechanism mechanism
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Real-time simulation: Mw7.8, Mentawai 2010
high high tsunami tsunami potential potential
TT0 119s 0 119s
OT+10min
MMwpd 7.7 wpd 7.7
focal focal mechanism mechanism
off-line simulation of Early-est realtime monitor - early-est.rm.ingv.it
Tsunami early warning within 5 minutes Conclusions
Further information:
We present procedures using real-time seismogram data currently available for most parts of the world to:
early-est.rm.ingv.it
1) Estimate within 5 min after an earthquake occurs the potential of the earthquake to generate a significant tsunami ● ●
●
Td∙T50Ex and Td∙T0 period-duration discriminants, give more and earlier information on tsunami impact than MwCMT or teleseismic T0, possibly identifies directly the “tsunami” faulting potential of an earthquake.
2) Determine within 10 min after an earthquake occurs an accurate magnitude, Mwpd, giving the true size of very large earthquakes ●
extension of Mwp to full P-wave duration T0.
3) Provide basic faulting parameters to aid in early tsunami forecast modeling
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●
●
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early-est.alomax.net
Lomax, A. and A. Michelini. Tsunami early warning within 5 minutes, PAGEOPH, submitted. Lomax, A. and A. Michelini, 2011. Tsunami early warning using earthquake rupture duration and Pwave dominant-period: the importance of length and depth of faulting, Geophys. J. Int., 185, 283–291, doi: 10.1111/j.1365-246X.2010.04916.x. Lomax, A. and A. Michelini, 2009B. Tsunami early warning using earthquake rupture duration, Geophys. Res. Lett., 36, L09306, doi:10.1029/2009GL037223 Lomax, A. and A. Michelini, 2009A. Mwpd: A durationamplitude procedure for rapid determination of earthquake magnitude and tsunamigenic potential from P waveforms, Geophys. J. Int., 176, 200–214, doi:10.1111/j.1365-246X.2008.03974.x
This work is supported by the 2007-2009 Dipartimento della Protezione Civile S3 project, INGV institutional funds and the EC NERA Project (n. 262330) The IRIS DMC and GFZ provided access to waveforms used in this study.
Anthony Lomax ALomax Scientific, Mouans-Sartoux, France -
[email protected]
Alberto Michelini Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy
[email protected]
Real-time: Mw9.1, Tohoku, Japan 2011 OT+7min
Real-time: Mw9.1, Tohoku, Japan 2011 OT+15min
Real-time: Mw8.6, Sumatra 2012
OT+5min
Real-time: Mw8.6, Sumatra 2012
OT+10min
