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Surface Wave Propagation through the Bohemian Massif Preliminary Results from the PASSEQ Experiment. Jiri Malek Petr Kolinsky Oldrich Novotny Renata Gazdova and PASSEQ working group Institute of Rock Structure and Mechanics Academy of Sciences of the Czech Republic. ESC 200 8 - PowerPoint PPT Presentation
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Surface Wave Propagation through the Bohemian Massif Preliminary Results from the PASSEQ Experiment
Jiri MalekPetr KolinskyOldrich NovotnyRenata Gazdovaand PASSEQ working group
Institute of Rock Structure and MechanicsAcademy of Sciences of the Czech Republic
ESC 2008September 2008
Hersonissos, Crete, Greece
Malek, Kolinsky, Novotny and Gazdova: Surface waves 2
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of the Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 3
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
PASSEQ - Passive Seismic Experiment in the Trans-European Suture Zone
Experimental part:May 2006 - June 2008
147 SP and 49 BB stations inPolandGermanyCzech Republicand Lithuania
Surface wave analysisPreliminary results from the Bohemian MassifData from PASSEQ and from the Czech Regional Seismic network
Malek, Kolinsky, Novotny and Gazdova: Surface waves 4
Selected earthquakes for surface wave studies
56 earthquakes MS>5.5 with a good azimuthal coverage
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 5
Azimuthal coverage at station Pruhonice (PRU)
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 6
Continental pathKurile IslandsM 8.1 and M 8.38.600 km
Mainly oceanic pathScotia SeaM 7.013.000 km
Different group velocity dispersion (source - station)
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 7
Different group velocity dispersions (source - station)Continental pathKurile IslandsM 8.1 and M 8.38.600 km
Mainly oceanic pathScotia SeaM 7.013.000 km
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 8
Same phase velocity dispersions (station - station)
Kurile IslandsM 8.1 and M 8.3
Scotia SeaM 7.0
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 9
Time-frequency transformation
• multiple filtering with Gaussian filters• constant relative resolution filtering• instantaneous period estimation
0.0 0.1 0.2 0.3 0.4 0.5 0.6frequency (Hz)
ampl
itude
pow er spectrumG aussian filte rsfilte red power spectra
Surface wave analysis – SVAL programKolinsky (2005)Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 10
Frequency-time spectrogram
period (s) period (s)
velo
city
(km
/s)
velo
city
(km
/s)
Truncated fundamental mode
Selection of fundamental modeContents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 11
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Set ofquasi-harmonic signals
Kurile Island M=8.3
Malek, Kolinsky, Novotny and Gazdova: Surface waves 12
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Set ofcoherent signalsat two stations
(time shift = 41 s)
Malek, Kolinsky, Novotny and Gazdova: Surface waves 13
R
T
2400 280 0 3200 360 0 4000
tim e from orig in (s)
RT
R
240 0 2800 3200 3600 4000
tim e from orig in (s )
R
2500 300 0 3500 400 0
t im e from orig in (s)
R
2500 3000 3500 4000
t im e from orig in (s)
R
2400 2800 3200 3600 4000
t im e from origin (s)
30 s 60 s 90 s 120 s 150 s
R
T
1600 2000 2400 280 0
tim e from orig in (s)
RT
R
1600 2000 2400 2800
tim e from origin (s )
R
1600 2000 2400 2800
tim e from origin (s)
R
1600 2000 2400 2800
tim e from origin (s)
R
1600 2000 2400 2800
tim e from orig in (s)
30 s 60 s 90 s 120 s 150 s
KurilIslands
8700 km
Scotia Sea
13000 km
Particle motion in horizontal planeContents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 14
Forward modeling- Dispersion curves are computed by a matrix method
- Modified Thomson – Haskell matrices
Proskuryakova et al. (1981)
Inversion- Isometric Method (IM)
- Non-linear inverse problems with many parameters
Malek et al. (2005 and 2007)
StructureContents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 15
- Love wave phase velocity inversion: vS model
- Rayleigh wave phase velocity inversion: vS and vP/vS ratio
- depths of interfaces are fixed during the inversion
ParametersContents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 16
S-wave velocity model of the Bohemian Massif
Czech Republic
PolandGermany
Austria Slovakia
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of the Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 17
SOUTHERN GREECEMS = 6.3 D = 1393 km from KHUContents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Z
R
T
200 300 400 500 600 700 800tim e from orig in [s]
08.06.08
Malek, Kolinsky, Novotny and Gazdova: Surface waves 18
ICELANDMS = 6.3 D = 2640 km from HAJ
Z
R
T
350 450 550 650 750 850 950 1050 1150 1250 1350tim e from orig in [s]
29.05.08
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 19
EASTERN SICHUAN, CHINA MS = 7.9 D = 7452 km from JAC
Z
R
T
600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800tim e from orig in [s]
12.05.08Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
Malek, Kolinsky, Novotny and Gazdova: Surface waves 20
Mean dispersion curveContents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200period (s)
3.0
3.4
3.8
4.2
4.6
5.0ph
ase
velo
city
(km
/s)
R ayle igh w avephase velocity
d ispersion curves
Malek, Kolinsky, Novotny and Gazdova: Surface waves 21
red line - present study, violet line - vSV (model STW105)
Kustowski B., Ekström G., and A. M. Dziewoński (2008), Anisotropic shear-wave velocity structure of the Earth's mantle: A global model , J. Geophys. Res., 113.
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions2.0 2.5 3.0 3.5 4.0 4.5 5.0
shear w ave veloc ity [km /s]
200
150
100
50
0
dept
h [k
m]
Malek, Kolinsky, Novotny and Gazdova: Surface waves 22
Conclusions- PASSEQ data were used for determination of an S-wave velocity model of the Bohemian Massif down to 200 km from surface waves dispersion.
- Rayleigh wave phase velocity dispersion curves between couples of stations were studied.
- Low velocity channel (astenosphere) was found in the depths of 50 – 145 km.
- Astenosphere is more pronounced than in the average world model STW 105.
Many thanks to Jan Zednik for data from the Czech Regional Seismic Network
Contents
PASSEQ experiment
Surface wave analysis
Mean S-wave model of Bohemian Massif
Conclusions
