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Neotectonics of the karamik graben-Afyon- (Isparta Angle), Sw Turkey

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2009
Çiçek, Aydın
The Karamık Graben (KG) is 6-17-km-wide, 29-km-long and NNE-SSWtrending active depression located within the Isparta Angle of the Southwestern Turkey extensional neotectonic domain. The KG is bounded by ENE-SSWtrending Karacaören fault zone to the south, the NNE-SSW-trending Koçbeyli- Akkonak fault zone to the east, the WNW-ESE-trending Akşehir fault zone to the north, and the NE-SW to NNE-SSW-trending Devederesi fault zone to the west. The KG contains two graben infills separated by an angular unconformity: (1) Middle Miocene-Middle Pliocene deformed infill, and (2) the Upper Pliocenerecent non-deformed infill. Some geological structures reveal that the older infill was accumulated under the control of an extensional tectonic regime (phase-I extension). Analysis of NW-SE-trending folds and some strike-slip faults indicate that the older infill deformed by a short-term NE-SW-directed compression. This contractional event is the last record of the paleotectonic period. Some geological and geophysical evidence indicate that the younger infill has been deposited under the control of an extensional tectonic regime (phase-II extension). Analysis of some slickensides implies that the current tectonic regime is being characterized by a multi-directional extension in predominantly N-S, E-W and NW-SE directions. This multi-directional extension dominates the Plio- Quaternary neotectonic period initiated Late Pliocene. Total throw amounts accumulated along the margin boundary faults imply that subsidence rates are ~0.15 mm/yr and ~0.21 mm/yr since Late Pliocene. Some of the northern margin-boundary faults of the KG reactivated during the neotectonic period as evidenced by 2002.02.02 Mw = 6.5 Çay earthquake. However, the rest of these faults are still active and they keep their nature of seismic gap.