Asperity along the North Anatolian Fault imaged by magnetotellurics at Düzce, Turkey
© The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB. 2009
Received: 29 April 2008
Accepted: 8 April 2009
Published: 31 August 2009
The magnetotelluric (MT) method has been applied to show resistivity variations in the vicinity of the epicenter of the 1999 Düzce earthquake (Mw = 7.2) where a large rupture velocity difference was seen between the western and eastern parts of the epicenter. MT data for frequencies ranging between 320 and 0.0005 Hz were acquired along two parallel profiles to the west and the east of Düzce earthquake’s epicenter. Both profiles crossed the Düzce basin and the Düzce fault in the north and the North Anatolian Fault (NAF) in the south. MT data analysis shows almost two-dimensionality in the region, at the depth starting from 2–3 km beneath the surface. According to two-dimensional MT modeling, a higher resistive layer extends beneath the eastern side of Düzce earthquake epicenter, compared with the western side. This resistivity structure correlates well with the aftershock distribution of the Düzce earthquake.