4.2. Stress transfer from AVD to NTF
The stress tensor produced by the AVD ruptures that were obtained in a
study by Momeni et al., (2019) is computed on the region using the same
method mentioned in section 4.1. As was also reported by Momeni et al.,
(2019), the stress field shows a positive Coulomb stress transfer of
>0.1 bar on most of the creeping segment of NTF, and also
~0.1 bar on the NBF (Fig. 4a). The two peaks of
cumulative scalar seismic moments of earthquakes are observed in these
segments on NTF and NBF from the 2012 AVD until the 2019 TKC (Fig. 2b).
A cumulative positive normal stress transfer of >0.1 bar is
obtained from AVD on most of the creeping segment of NTF (Fig. 4b). This
additional positive normal stress to the regional stress may increase
the effective normal stress on the creeping segment and change its
rheology from partial creep to more stick-slip. The occurrence of two
earthquakes on the proposed creep segment after the AVD which is also
observed as a peak of the scalar seismic moment in Figure 2d confirms
our suggestion.
On the NMF, two a wide peak of the cumulative scalar seismic moment was
observed North of Urmieh Lake before AVD. While after the doublet, there
is a peak of the cumulative scalar seismic moment in between of the
previous wide peak suggesting that this part was partially locked, and
has been excited by the doublet. Also, these seismic activities may be
partly related to the relatively higher pore-fluid pressure provided by
the Urmieh Lake on the NMF, or by the recent dramatic decrease of 90%
of the water volume of the lake during years 1995 to 2013 (Schulz et
al., 2020) that may reduce the effective normal stress on NMF, unclamp
it, and excite it to slip.