抄録
On January 10, 1998, an earthquake with a magnitude of 6.2 occurred in the northwestern Hebei Province, China. The earthquake killed approximately 50 persons and caused widespread damage. The epicenter was at the cross location between two active fault zones, striking E-W and NNE-SSW to NE-SW, located on the north and east edges of the Ordos tableland, respectively. More than 50 strong earthquakes (M≥6) have occurred along the active faults surrounding the Ordos tableland. The native people found some anomalous behavior of animals and luminous phenomenon just before the earthquake. Some peasants reported that, after anomalous light at the early stage of the ground motion, flows of white smoke or vapor came from the fissures. The most damaged area, forming an ellipse with the strike of N-S to NNE-SSW, was centered 8-10 km away from the epicenter, where more than 70-90 % buildings were damaged. Many chimneys and gate pillars of stone fence walls were broken and fell in the SSE-SSW direction at the western side of the inferred surface trace of seismic fault and to the NNE-NNW direction at the eastern side. Aftershocks were concentrated in the most damaged area.
Based on the data of the earthquake mechanism, the aftershocks, the damaged area, and the downfallen directions of the chimneys and gate pillars, it is inferred that the surface trace of the seismic fault strikes NNE and dips west.
