Zakynthos 2018/10/25

Bibliography

  • Note on the modelling of the GNSS data (28/1/2019)
  • Cirella A. et al., 2020. The 2018 Mw 6.8 Zakynthos (Ionian Sea, Greece) earthquake: seismic source and local tsunami characterization, GJI, 221, 2, 1043-1054, https://doi.org/10.1093/gji/ggaa053   [pdf]
  • Chousianitis K. and Konca A., Intraslab deformation and rupture of the entire subduction crust during the 25 October Mw 6.8 Zakynthos earthquake, GRL, 46, 24, 14358-14367.
  • Sokos E. et al., 2020, The 2018 Mw 6.8 Zakynthos, Greece, earthquake: dominant strike-slip faulting near subduction slab, Seismological Research Letters, 91 (2A), 721-732.

 

Fault location and parameters inferred from the modelling of the displacement at the GPS station

Parameter

Unit

Co-seismic

Post-seismic

Long(1)

°

20.625 ± 0.01

20.625 ± 0.02

Lat(1)

°

37.415 ± 0.01

37.415 ± 0.02

Depth

km

3 ± 1

0 ± 1

Length

km

26 ± 3

26 ± 6

Width

km

16.5 ± 2

3 ± 2

Strike

°

9 ± 6

9 ± 25

Dip

°

25 ± 5

90 ± 40

Rake

°

170 ± 6

180 ± 25

Slip

m

1.93 ± 0.1

1.9 ± 0.5

Moment

N m

2.73 1019

0.44 1019

Centroid

km

6.5

1.5

Parameters of the fault in the « inverse6 » format: zaky7.fai

 

Model of tsunami calculated with CLIONA (©CEA/DASE) (processing of 2020/03/02) by Simon Bufféral using the above parameters for the fault

Animation with input parameters « model7 » (above) – see GIF

Location of the real and theorical tide gauges

Location of the real (R) or theoretical (T) tide gauges

Code Status East North Note
zaky T 20.90524 37.78163 Entrance of the harbour of Zakynthos
kypa R 21.66434 37.25933  
lixo T 20.44213 38.20181 Harbour of Lixourion
pylo T 21.69489 36.91665 Harbour of Pylos
agso T 20.86407 37.71599 Harbour of Agios Sostis
kata R 21.32052 37.64904  
pylo1 T 21.67329 36.90737 Island and the entrance of the Pylos bay
nava1 T 21.64530 36.99514 Assumed a buoy 50m in front of the Navarino Environmental Observatory
koro T 21.95986 36.79756 Harbour of Koroni
meto R 21.70786 36.81402 Harbour of Methono
meto1 T 21.70259 36.81597 West of the fortress of Methoni, 50m off-shore (assumed to be a buoy)
stro1 T 21.01383 37.25121 Strofades, assumed a buoy 50m off-shore in front of the chapel


Modelled waves using the « model7 » (here the calculation is made for 7200 seconds (two hours) after the rupture assummed to be at 22:54:51.5 UTC according to the EMSC.

Fit of the data acquired at KATA and KYPA

 

Parametric analysis

At the sites AGSO, KATA, KYPA, METO, METO1, NAVA1, PYLO1, STRO1 we analyzed the perturbations of the model7 induced by changes of the  the following parameters:

  • longitude (long): nominal 20.71°, tested 20.60°
  • model7 – azimuth (azm): nominal 9°, tested : 19° and 359°
  • model7 – dip angle (dip): nominal 25°, tested : 15° and 35°
  • model7 – depth of centroid (depth):  nominal 6.5 km, tested 3.5 km and 9.5 km 
  • model7 – depth of upper edge of the fault (dmin): nominal 3 km, tested 0 km and 6 km
  • model7 – rake (rak): nominal 170°, tested 160° and 180°