Interference analysis of the extensometer observation at Xuzhou seismic station

The extensometer of Xuzhou seismic station is mainly disturbed by rainfall and atmospheric pressure. The influence of rainfall and atmospheric pressure on extensometer is quantitatively analyzed. The results show that the response of EW component rainfall is more sensitive. The main reason for the rapid acceleration of observation data in a short time is that the sensor core is not centered in the differential voltage transformer sensor. The induced area of the biased sensor core in the differential voltage transformer sensor increases greatly, leading to an increase of the induced voltage in the observation.