The Tyrnavos Fault (TF) is an ESE-WNW trending, north-dipping dip-slip normal fault representing one of the major tectonic structures bordering the Late Pleistocene-Holocene Tyrnavos Basin, Northern Thessaly, Greece. The fault affects Quaternary and Pliocene deposits and mainly the Triassic crystalline limestone of the Pelagonian basement. According to previous researches, the TF has been clearly geometrically and kinematically characterised. A well-defined fault trace has been mapped for more than 12 km, while with the aid of remote sensing techniques it can be tentatively followed further East across the northern Larissa Plain, thus giving a possible total length of almost 20 km. Several well documented morphological features observed along the fault and associated to it in a broader area have been interpreted as surface expressions of recent movements. In this note, the results of a palaeoseismological investigation carried out along the fault will be presented and discussed. Six trenches have been excavated and logged in detail in order to obtain information about the characteristics of past earthquakes. Numerous samples have been also collected for absolute dating that has been performed with different techniques like TL, OSL and AMS. The sedimentological, structural and chronological data collected document a Late Pleistocene to Holocene morphogenic activity of the TF, which is characterised by vertical co-seismic displacements of 15-40 cm and likely return periods of several thousands years. Our results suggest the occurrence of a possible seismic gap along the TF. Implications for the seismic hazard of this highly populated region will be also discussed.
Palaeoseismological researches along the Rodia Fault, Central Greece
CAPUTO, Riccardo;
2004
Abstract
The Tyrnavos Fault (TF) is an ESE-WNW trending, north-dipping dip-slip normal fault representing one of the major tectonic structures bordering the Late Pleistocene-Holocene Tyrnavos Basin, Northern Thessaly, Greece. The fault affects Quaternary and Pliocene deposits and mainly the Triassic crystalline limestone of the Pelagonian basement. According to previous researches, the TF has been clearly geometrically and kinematically characterised. A well-defined fault trace has been mapped for more than 12 km, while with the aid of remote sensing techniques it can be tentatively followed further East across the northern Larissa Plain, thus giving a possible total length of almost 20 km. Several well documented morphological features observed along the fault and associated to it in a broader area have been interpreted as surface expressions of recent movements. In this note, the results of a palaeoseismological investigation carried out along the fault will be presented and discussed. Six trenches have been excavated and logged in detail in order to obtain information about the characteristics of past earthquakes. Numerous samples have been also collected for absolute dating that has been performed with different techniques like TL, OSL and AMS. The sedimentological, structural and chronological data collected document a Late Pleistocene to Holocene morphogenic activity of the TF, which is characterised by vertical co-seismic displacements of 15-40 cm and likely return periods of several thousands years. Our results suggest the occurrence of a possible seismic gap along the TF. Implications for the seismic hazard of this highly populated region will be also discussed.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
