Tectonic Geomorphology of the Hoyran Graben (Western Anatolia, Türkiye): Insights From Geomorphic Indices

Abstract

The area be tween West ern Anatolia and Isparta Bend com prises nu mer ous de pres sions and the ac tive faults that bound them. The Hoyran Graben is one of these de pres sions, lo cated at the north ern most part of the Isparta Bend. This NE-SW-ori ented graben is bounded by the Hoyran Fault in the north west and the Uluborlu, Senirkent and Kumdanli faults in the south-east, re spec tively. We eval u ate the seis mic ac tiv ity po ten tial among seg ments of the bound ary faults in the light of field work and morphometric in di ces. These bound ary faults of the Hoyran Graben are di vided into twelve seg ments for the analysis, with indices used including mountain-front sinuosity (Smf: 1.05-2.02), val ley floor width-to-val ley height ra tio (Vf: 0.11-1.34), hypsometric curve and in te gral (Hi: 0.4-0.73), asymmetry factor (Af: 13.76-87.03), stream length-gra di ent (SL: 1.48-9450) and nor mal ized chan nel steep ness (Ksn: 2.38-990.38). The re sults ob tained, to gether with field ob ser va tions, in di cate that the Uluborlu, Senirkent and Kumdanli faults, as well as the west ern seg ments of the Hoyran Fault, rep re sent higher po ten tial in terms of seis mic ac tiv ity with up lift rates >0.5 mm/y, while the cen tral and east ern seg ments show mod erate ac tiv ity with up lift rates be tween 0.05 and 0.5 mm/y. Thus, the bound ary faults of the Hoyran Graben need fur ther at ten tion in terms of re gional seis mic haz ard.