北アナトリア断層 (トルコ) 東部地域の地震断層について

抄録

The North Anatolian Fault is one of the largest strike slip faults (right lateral) in the world and is believed to be a transform fault between Eurasian Plate and Anatolian Plate (Turkey Plate). Many large earthquakes (M>6.5) and related earthquake faults happened to occur along this active fault. It is well known that the migration of those epicenters to westward along the fault since Erzincan Earthquake in 1939. Most of earthquake faults related to those earthquakes have multi-echelon structures. In Erzincan area, main five segments of Erzincan earthquake fault are distinguished, that is, Mihar, Bahik, Hilir, Altintepe and Tanyeri segment from the west to the east. Their length are less than 20km. Though their displacement of each segment shows right lateral one with a slight vertical component, their alingment is not always right lateral echelon pattern. It is rahter resulted from the geological and geomorphological aeolotropic of the surface.
The result of the measurement of relative Rn concentration by a track etch method at Mihar, Bahik, Hilir and Ismetpasa shows that the peak of track numbers appears mostly on the fault lines. So the a track etch method is effective for the detection of radon ema-nation relating to the earthquake faults. It is expected empirically that the track numbers observed on thin Quaternary cover sediment is generally larger than that on thick Quater-nary cover sediment crossing the active faults. In this case, the numbers of α tracks are less than the expected one though there is very thin or no Quaternary strata. This may be because that the basement rocks, for example, serpentin has little Rn and/or that the weathered clay originated from the fractured serpentine interrupted the carring out of the gas including Rn.