VERTICAL CRUSTAL DEFORMATION AND SEISMIC RISK ANALYSIS IN CAPITAL AREA AND NORTHERN PART OF SHANXI DOWNFAULTED ZONE

the vertical crustal deformation in recent 10 years is analyzed with repeated leveling data observed in Capital area and northern part of Shanxi downfaulted zone. The results show that the northeast region of the area is descending entirely with a rate of 2~4mm/ya, but the state of "uplifting in north and descending in south" is not changed. The area from west of Taihangshan Mountain to east of Shanxi downfaulted zone is uplifting with a rate nearly 8mm/ya. The distribution has changed gradually from entirely uplifting with a speed "rapid in south and slow in north" to "uplifting in north and descending in south". The variation in west area is divided by the year of 2001, and a four-quadrant deformation pattern has formed in Yanhuai Basin and its surrounding area. The pattern is smaller than that of before Datong earthquake both in scale and magnitude. The movement in northern part of Shanxi downfaulted zone shows vertical downfaulted character with a rate of 4~6mm/ya. The characteristics above mentioned indicates that over 6 earthquakes might not occur in recent 2~3 years in the area.