UHF Electromagnetic Perturbation due to the fluctuation of Conductivity in a Fault Zone

단층대의 전기전도도 변동에 의한 UHF 전자기장 교란

  • Lee Choon-Ki (Dept. of Earth Science Education, Seoul National University) ;
  • Lee Heuisoon (Dept. of Science Education, Gyeongin National University of Education) ;
  • Kwon Byung-Doo (Dept. of Earth Science Education, Seoul National University) ;
  • Oh SeokHoon (Marine Meteorology & Earthquake Research Lab., Meteorological Research Institute) ;
  • Lee Duk Kee (Marine Meteorology & Earthquake Research Lab., Meteorological Research Institute)
  • 이춘기 (서울대학교 지구과학교육과) ;
  • 이희순 (경인교육대학교 과학교육과) ;
  • 권병두 (서울대학교 지구과학교육과) ;
  • 오석훈 (기상연구소 해양기상지진연구실) ;
  • 이덕기 (기상연구소 해양기상지진연구실)
  • Published : 2003.05.01

Abstract

ULF geomagnetic field anomalies related to earthquakes have been reported and a mechnism that magnetic field variations could be generated by the induced telluric current due to the high frequency fluctuation of conductivity in a fault Bone have been proposed. In this study, we calculated electromagnetic anomalies using a simple fault model and investigated the possibility of significant perturbation. Since low frequency electromagnetic fields are modulated by the high frequency oscillation of conductivity and the modulated fields are concentrated in a narrow ULF band, the electromagnetic fields in ULF band could be perturbed significantly. The amplitude of electromagnetic field anomaly depends on various factors: the geometry and conductivity of fault zone, the magnitude and frequency of conductivity fluctuation, the resistivity structure of crust or mantle, the frequency bandwidth of observational data and so on. Therefore, it is strongly required to reveal the deep resistivity structure of crust a.: well ah the structure of fault zone and to ,select the optimal observation frequency band for the observation of electromagnetic activities related with earthquakes.