2008年5月12日14时28分在四川汶川发生了8.0级大地震，距离徐州台1392.0Km徐州台的两台体积应变仪在14时34分记录到该次地震，在记录到地震波动和同震阶跃的同时，有一台仪器在较大波动幅度的影响下产生了自动调零（电磁阀门开启），调零信息和地震信息混在一起，难以直接使用原始数据。是否能够、以及如何合理地消除自动调零带来的影响，真实还原本来的真实情况，成为台站必须解决的问题。我们采取的科学确定校正值的方法，力图还原为连续记录，此方法得到了初步的验证：处理后的资料可以和另外一台没有调零动作的体积应变仪器的原始资料相符合。

An 8.0 earthquake occurred  14:28 on May 12, 2008 in Wenchuan,Sichuan, 1392.0 km away from my unit. Two volumetric strain instruments that belongs to xuzhou station recorded the seismic wave and the coseismic step of this earthquake at 14:34 ,at the same time one of these two instruments arose automatic zero under the influence of the large fluctuation (solenoid valve opens) ,and it becomes very hard to use the original data when the automatic zero information and the Earthquake Information mixed. We have to solve the problem whether and how to reasonably eliminate the impact of auto-zero, true to restore the original situation. We adopted the scientific method of determining the correction value ,trying to restore a continuous record ,this method has been initially verified:the processed data and the original data produced by another volumetric strain instruments without automatic zero were consistent.