20. Processo de ruptura dos sismos de Sumatra de 2004 e 2005
20. Processo de ruptura dos sismos de Sumatra de 2004 e 2005
20. Processo de ruptura dos sismos de Sumatra de 2004 e 2005
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Universida<strong>de</strong> <strong>de</strong> Évora<br />
Universida<strong>de</strong> <strong>de</strong><br />
Évora<br />
DFIS e Centro <strong>de</strong> Geofísica <strong>de</strong> Évora<br />
<strong>Processo</strong> <strong>de</strong> Ruptura <strong>dos</strong> <strong>sismos</strong> <strong>de</strong> <strong>2004</strong> e<br />
<strong>2005</strong><br />
José Fernando Borges, Bento Cal<strong>de</strong>ira e Mourad Bezzeghoud<br />
Dpto. . <strong>de</strong> Física F<br />
e Centro <strong>de</strong> Geofísica <strong>de</strong> Évora, Universida<strong>de</strong> <strong>de</strong> Évora, Portugal - jborges@uevora.pt<br />
SEGUNDO ENCONTRO DE PÓS-GRADUAÇÃO EM<br />
INVESTIGAÇÃO E ENSINO DAS CIÊNCIAS FÍSICAS<br />
E DA TERRA DA UNIVERSIDADE DE ÉVORA<br />
DFIS e CGE<br />
1 e 2 <strong>de</strong> Outubro <strong>de</strong> <strong>2005</strong>
Universida<strong>de</strong> <strong>de</strong> Évora<br />
Sismo <strong>de</strong> <strong>Sumatra</strong> <strong>de</strong> <strong>2004</strong><br />
Mw=9.3)<br />
DFIS e CGE
Universida<strong>de</strong> <strong>de</strong> Évora<br />
Da<strong>dos</strong>:<br />
Formas <strong>de</strong> onda Broad Band IRIS DMC :<br />
26/12/<strong>2004</strong> - 29 formas <strong>de</strong> onda telesísmicas P<br />
28/03/<strong>2005</strong> - 23 formas <strong>de</strong> onda telesísmicas P<br />
Método<br />
Directivida<strong>de</strong><br />
Cálculo da velocida<strong>de</strong> e direcção <strong>de</strong> <strong>ruptura</strong> observa<strong>dos</strong> em pulsos comuns<br />
empregando o programa DIRDOP (DIRectivity DOPpler effect) (Cal<strong>de</strong>ira, <strong>2005</strong>)<br />
Inversão<br />
Método <strong>de</strong> inversão <strong>de</strong> Kikuchi and Kanamori (2003) algoritmo baseado na<br />
inversão do <strong>de</strong>slizamento sobre o plano <strong>de</strong> falha. Os da<strong>dos</strong> foram filtra<strong>dos</strong><br />
com um filtro passa- banda entre 0.002–2 Hz e <strong>de</strong>pois converti<strong>dos</strong> em<br />
<strong>de</strong>slocamento com uma frequência <strong>de</strong> amostragem <strong>de</strong> 1Hz.<br />
DFIS e CGE
Universida<strong>de</strong> <strong>de</strong> Évora<br />
Sismicida<strong>de</strong> Global – 1900-1999<br />
1999<br />
INTERNATIONAL HANDBOOK OF EARTHQUAKE & ENGINEERING SEISMOLOGY, 2003, ACADEMIC PRESS<br />
DFIS e CGE<br />
M≥6.5<br />
h
Universida<strong>de</strong> <strong>de</strong> Évora<br />
( USGS)<br />
6cm/ano<br />
6cm/ano<br />
DFIS e CGE
SUBDUCÇÃO<br />
Caso <strong>de</strong> <strong>Sumatra</strong>
Universida<strong>de</strong> <strong>de</strong> Évora<br />
0 S 2 Fornece um<br />
momento sísmico <strong>de</strong><br />
Mo = 1 x 10 22 Nm<br />
(Mw=9.3)<br />
Momento Sísmico<br />
Nature,<br />
31/03/<strong>2005</strong><br />
<strong>Sumatra</strong><br />
<strong>2004</strong><br />
3 x maior que os o valor<br />
obtido pelas ondas<br />
superficiais e volúmicas<br />
Comparando a área <strong>de</strong><br />
falha com momento, a<br />
magnitu<strong>de</strong> e a<br />
<strong>de</strong>slocamento po<strong>de</strong>mos<br />
concluir que estamos na<br />
presença <strong>de</strong> um<br />
MEGASISMO<br />
Mo = µ x A x D<br />
Mw = Log Mo/1.5 - 10.3<br />
Açores<br />
1980<br />
Lisboa<br />
1755<br />
DFIS e CGE<br />
Mw=7.0 Mw=9.0 Mw=9.3
Universida<strong>de</strong> <strong>de</strong> Évora<br />
Directivida<strong>de</strong><br />
26 December <strong>2004</strong><br />
293 o<br />
0-130s vr=2.7±0.6 km/s NW<br />
DFIS e CGE
Universida<strong>de</strong> <strong>de</strong> Évora<br />
Directivida<strong>de</strong><br />
26 Dezembro <strong>2004</strong><br />
0 30 90 130<br />
249 o<br />
0-30s<br />
293 o<br />
30-90s<br />
286 o<br />
90-130s<br />
DFIS e CGE<br />
1) 0-30s vr=0.5±0.5 km/s -> Ruptura bilateral<br />
1) 30-90s vr=1.9±0.3 km/s -> NW<br />
2) 90-130s vr=2.7±0.6 km/s -> NW
Universida<strong>de</strong> <strong>de</strong> Évora<br />
Directivida<strong>de</strong> 28 March <strong>2005</strong><br />
151 o<br />
0-27s vr=3.3±0.6 km/s SE<br />
DFIS e CGE
Universida<strong>de</strong> <strong>de</strong> Évora<br />
M oI =2.8x10 21 Nm<br />
Mw=8.3<br />
Inversão – <strong>Sumatra</strong> <strong>2004</strong><br />
26 December <strong>2004</strong><br />
Focal Mechanism<br />
Função Temporal da Fonte<br />
M o =2.9 x 10 22 Nm;<br />
M w =9.0<br />
?<br />
II<br />
M oII<br />
=2.0 x10 22 Nm ; Mw=8.8<br />
I<br />
N55W<br />
I<br />
Distribuição do slip ao longo do plano N15W<br />
5.0 m<br />
II<br />
D max<br />
=14 m<br />
DFIS e CGE
Universida<strong>de</strong> <strong>de</strong> Évora<br />
Inversion<br />
26 December <strong>2004</strong><br />
P-waveform comparison<br />
observed<br />
synthetic<br />
DFIS e CGE<br />
Solid line for the observed seismogram and thin red line for the synthetic seismogram
Universida<strong>de</strong> <strong>de</strong> Évora<br />
Mecanismo Focal<br />
Inversão<br />
28 Março <strong>2005</strong><br />
M o =0.82 x 10 22 Nm;<br />
M w =8.6<br />
Slip Distribution along the fault plane<br />
D max<br />
=12 m<br />
Star indicates the hypocenter<br />
DFIS e CGE<br />
Results obtained from inversion of teleseismic P-wave using Kikuchi<br />
and Kanamori (2003) program
Universida<strong>de</strong> <strong>de</strong> Évora<br />
Inversion<br />
28 March <strong>2005</strong><br />
P-waveform comparison<br />
observed<br />
synthetic<br />
DFIS e CGE<br />
Solid line for the observed seismogram and thin red line for the synthetic seismogram
Universida<strong>de</strong> <strong>de</strong> Évora<br />
26/12/<strong>2004</strong><br />
M =9.0 w<br />
Distribuição espacial<br />
e temporal do<br />
<strong>de</strong>slizamento<br />
28/03/<strong>2005</strong><br />
M =8.6 w<br />
Comparação<br />
DFIS e CGE
Universida<strong>de</strong> <strong>de</strong> Évora<br />
Conclusões<br />
Sismo 26 Dezembro <strong>2004</strong><br />
1. L= 930 km<br />
2. vr=2.7 km/sec<br />
3. T= 350 sec<br />
4. 3 asperities<br />
5. Mo= 2.9x10 22 Nm (Mw=9.0)<br />
6. Dmax= 14 m<br />
DFIS e CGE
Universida<strong>de</strong> <strong>de</strong> Évora<br />
Conclusões<br />
Sismo 28 Março <strong>2005</strong><br />
1. L= 425 km<br />
2. vr=3.3 km/sec<br />
3. T= 110 s<br />
4. 2 asperida<strong>de</strong>s<br />
5. Mo= 2.2x10 21 Nm (Mw=8.6)<br />
6. Dmax= 11 m<br />
DFIS e CGE
Universida<strong>de</strong> <strong>de</strong> Évora<br />
Comparação entre a<br />
área <strong>de</strong> <strong>ruptura</strong> do<br />
sismo <strong>de</strong> <strong>Sumatra</strong><br />
(<strong>2004</strong>) e hipotéticas<br />
zonas <strong>de</strong> <strong>ruptura</strong> do<br />
sismo <strong>de</strong> 1755<br />
• A-B mo<strong>de</strong>lo <strong>de</strong> fonte<br />
proposto por by Baptista et<br />
al. 2003;<br />
• B-C, mo<strong>de</strong>l proposed by<br />
Vilanova (<strong>2004</strong>);<br />
• D – mo<strong>de</strong>l proposed by<br />
Gutscher (<strong>2004</strong>)<br />
DFIS e CGE