Spatial correlation of the aeromagnetic anomalies and seismogenic faults in the Marmara region, NW Turkey

Abstract

Previous investigations into the deep structure of the Marmara Sea region revealed an existence of a rigid barrier located at the centre of the Marmara Sea. Thus, the North Anatolian Fault (NAF) was divided into three segments to the west of this barrier. Seismological records of two 5 year periods (1998-2002 and 2003-2007) indicate a decrease of seismic activity oil and around this barrier. It was previously shown if the fault movement reaches to magma its fractures are filled with magmatic material causing magnetic anomalies. In this Study, advance processing methods are utilized to observe the spatial correlation between the aeromagnetic anomalies and the faults of the Marmara region. These are the reduction to the pole transformation (RTP) and anomalies and the faults of the Marmara second vertical derivative (SVD) methods. In particular, SVD map shows alignments which call be correlated with the faults. These faults are the Northern Boundary, Yalova, Armutlu, Imrali and Edincik faults. Length of the Northern Boundary Fault (NBF) is about 50-60 km. Thus, this fault Would not produce strong earthquakes. The Edincik Fault exends from east to the west and bends through WSW. The length of this fault in connection with the Imrali, Armutlu and Yalova faults in the cast exceeds 300 km and named the Main Fault Zone (MFZ) by the authors of this study. These faults as a whole may produce strong earthquakes. Some seismic gaps are observed along with the Imrali and Edincik faults from the earthquake distribution records of two 5 year periods ( 19982002 and 2003-2007). As a Conclusion, there are high-potentials of strong earthquake occurrences in these regions. (C) 2008 Elsevier B.V. All rights reserved.