The features and cause of hot anomaly in a well in Xinxiang,Henan province
CHANG Zu feng (Seismological Bureau of Xinxiang, Henan Province, Xinxiang\ 453003,China)
A high temperature water is found in a well in Xinxiang, Henan Province. The temperature of the water may rise to 40～250℃. By the approach of a series of site tests and investigation, it is discovered that the water temperature at the lower of the well is in normal, the temperature fluctuation only lies in the depth range of 10～35m. Based on the features of hot anomaly and the result of color spectrum analysis of dissolved gas, it may be preliminarily concluded that the hot anomaly is not resulted from structure activities. To find the real cause of the hot anomaly, some data reduction methods of digital filtering and corelation analysis are used for data processing.Long term groundwater abstraction accelerates the percolation from phreatic aquifer consisting of medium small grain sand.Further more. the subsurface flow near the pump is gradually mixed with the flow of another hot well and the hot anomaly therein occcurs.