AUTHOR=Hedger  Emily , Gottsmann  Jo 

TITLE=Investigating Stress Transfer Between the Tuz Gölü Fault Zone and Hasan Dağ Volcano (Turkey)

JOURNAL=Frontiers in Earth Science

VOLUME=Volume 9 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2021.732696

DOI=10.3389/feart.2021.732696

ISSN=2296-6463

ABSTRACT=The 27 km long Akhisar-Kilic ̧ fault segment (AKFS) of the seismically active Tuz Go ̈lu ̈ fault
 zone in the Central Anatolian Volcanic Province transects the north-eastern flank of the active
 Hasan Dag ̆ volcanic complex. Elevated footwall uplift rates in the vicinity of Hasan Dag ̆, and
 the surpassing of the calculated recurrence interval for fault segment rupture may indicate
 system criticality. Here we use Finite Element Analysis to quantify the Coulomb failure stress
 transfer between the fault segment, conjugate fault systems and Hasan Dag ̆’s magma reservoir,
 accounting for stress modulation by both topography and a mechanically heterogeneous crust.
The magnitude of current stress accumulation by aseismic slip on the AKFS since its most
recent rupture (5.45 ka±0.16 BP) is parameterised using the Coulomb Failure Stress change (∆CFS). The model predicts a currently accrued ∆CFS of between 2.5±0.2 and 15±0.5 MPa3 on the fault plane for published lower and upper-bound estimates of right-lateral aseismic slip
rates, respectively, and sufficient to promote failure of the segment. We show that protracted
 aseismic slip contributes to the progressive unclamping and transtensional opening
 of potential magma pathways oriented perpendicularly to the AKFS both above and below
 the reservoir thereby encouraging reservoir failure with potential for magma ascent to feed an
 eruption. The M5.1 20th of September 2020 earthquake SW of Hasan Dag ̆ occurred in a volume
 predicted by this study to have undergone fault unclamping due to aseismic slip along the AKFS.
 Earthquake magnitudes of between Mw5.94 and Mw6.76 due to hypothetical partial or complete
 rupture of the segment would further unclamp fractures perpendicular to the AKFS beneath and
 above the magma reservoir.. For the same range of moment magnitudes,
 modelled (∆CFS) both below and above the reservoir indicate clamping
 of fractures parallel to the AKFS. We find that the spatial pattern of (∆CFS) on Hasan Dag ̆’s magma reservoir is predominantly controlled by the location of rupture
relative to the reservoir with the magnitude of the earthquake playing a subordinate role. We
explore implications of our findings for the assessment of interconnected seismo-volcanic hazards
 and associated risks.