Auxiliary material for paper GRL50516
The 2011-2012 unrest at Santorini rift: Stress interaction between active faulting and volcanism.
Nathalie Feuillet
Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Univ. Paris Diderot, UMR 7154
CNRS, Paris, France.
This paper contains 8 auxiliary materials:
1- grl50516-sup-0002-txts01.pdf: Santorini rift geometry at depth in seismic and topographic
cross-sections (Text + references + figure S1 caption)
2- grl50516-sup-0003-fs01.eps : Figure S1. Santorini rift geometry at depth in seismic and
topographic cross-sections. Seismic (a) and topographic (b) profiles perpendicular to the
Santorini rift, profiles are located on the map. Seismic profiles interpretation modified from
Sakellariou et al. (2010). ATZ: Acoustically transparent zone corresponding to magmatic
intrusions within thick layered sedimentary units. Vertical exaggeration is equal to 28 for the
topographic profiles.
3- grl50516-sup-0004-txts02.pdf: Coulomb stress Modeling parameters and uncertainties (Text
+references+ figure S2 caption).
4- grl50516-sup-0005-fs02.eps : Coulomb stress Modeling parameters and uncertainties. Static
coulomb stress changes induced by the 2011-2012 magmatic inflation at Santorini in an
extensional stress regime. Red colors: areas of Coulomb stress increase; blue colors area of
Coulomb stress decrease. White double arrows: direction of local extension. Seismicity as in
Figure 3. Volcanic source parameters from Newman et al. (2012), see table 1. Faults as in Figure
2. Predicted focal mechanisms calculated for the left lateral optimally oriented planes for rupture
(OOP) are indicated in all figures except (a) where the focal mechanisms are calculated for the
right lateral OOP. White dashed line: area where the stress has increased by more than 2MPa,
Gray dashed area: area where the seismic swarm is much denser. a) Lamé’s coefficients are equal
to 32 GPa and μ’ = 0.4, The regional stress is deviatoric with |σ3| = |σ1|= 3 MPa, σ3 is horizontal
and strikes 135°E. b) as in a but with Lamé’s coefficients equal to 20 GPa. c) as in a) but with the
with a extensional preexisting regional stress oriented N155°E. f) As in e) but with a extensional
regional stress oriented N115°E. g) as in a) but with a lower regional stress with |σ3| = |σ1|= 0.5
MPa. h) as in g) but with a stronger regional stress with |σ3| = |σ1|=10MPa.
5- grl50516-sup-0006-txts03.pdf : Coulomb stress changes on N-S or E-W striking strike-slip
faults responsible for the 2012 seismic sequence south of Christiana. (Text + references + figure
S3 caption).
6- grl50516-sup-0007-fs03.eps : Coulomb stress changes on N-S or E-W striking strike-slip faults
responsible for the 2012 seismic sequence south of Christiana. Static coulomb stress changes
induced by the 2011-2012 magmatic inflation at Santorini rift (see model parameters in Table 1)
on fixed target faults defined by the nodal planes of the focal mechanism calculated by Kiratzi et
al., (2013) for the 26/01/2012 (4:24) mainshock, south of the Christiana fault. Red colors: areas
of Coulomb stress increase; blue colors area of Coulomb stress decrease. Contour interval: 0.002
MPa between -0.01 and 0.01 MPa. Seismicity, focal mechanisms, symbols and faults as in Figure
7- grl50516-sup-0008-txts04.pdf : Active faulting at Nysiros. (Text+ references+ figure S4
caption).
8- grl50516-sup-0009-fs04.eps : Active faulting at Nysiros. Active faulting around Nysiros
volcano. In red: active and late Quaternary faults with thicker traces for higher scarps. In black:
Older probably less active more E-W striking fault related to back-arc extension. Active faulting
and volcanic vents on Nysiros island from Tibaldi et al. (2008). Volcanic complexes in purple
with zones darker purple underlying volcanic vents developing in the center of Nysiros volcano
inside a small graben prolonging the Nysiros rift onshore.