TY - JOUR ID - 13090 TI - - JO - Journal of the Earth and Space Physics JA - JESPHYS LA - en SN - 2538-371X Y1 - 1998 PY - 1998 VL - 24 IS - 1 SP - EP - KW - aftershock activity KW - Bojnourd Earthquake KW - Seismicity and Seismotectonics of North-East Iran KW - source mechanism KW - Source parameters DO - N2 - The Feb. 4, 1997 Bojnourd earthquake of M 6.8 occurred in a mountainous area, North-East Iran, and caused extensive destruction. Relatively a fewer human lives were lost due to a strong foreshock. Field investigation and aftershocks distribution suggest a NW-SE faulting with a right-lateral strike-slip motion. Aftershock activity was scattered indicating that the mainshock activated the nearby minor faults. Aftershocks extended to a length of 45km and a depth of 20km. The average stress drop was estimated to be 20 bar and the static displacement was 35 em. Great destruction in the affected area was mainly caused by poor seismic resistance of traditional adobe houses. Well designed buildings in the epicentral region survived with minor damage. The ground-motion characteristics during the mainshock should be considered for the high safety design of structures in the damaged area. UR - https://jesphys.ut.ac.ir/article_13090.html L1 - https://jesphys.ut.ac.ir/article_13090_da7556f2203ad933e47946017a439b81.pdf ER -