Investigation and analysis of leveling deformation anomaly at Daixian station in Shanxi, China

The leveling measurements at Daixian station appeared increasing trend since March 25, 2013, which is credible, showing normal fault activity. According to the environmental survey, it contains some interference factors: first, the wind is big when the leveling measures in the afternoon, which has certain influence on the measurement results, but the impact is random and should be near the base value and not appear a trend. Second, the point BM3 was maintained during Sep. to Oct. in 2012 and occurred cracks in 2013, showing that the poor stability around the point. In addition, the change of recorded program is only to change the way of data record and can not affect the observation results during the same period.