在简化条件下,估计了压磁效应的可能量级.由此推知,在非磁异常区,地震前后的磁场变化不一定是压磁效应引起的.压磁效应不是震磁关系的唯一机制.按照渗滤电流理论推出的公式表明,由地下水渗滤作用引起的所谓膨胀磁效应也是很小的.只有渗滤区足够大,地下水剧烈运动,才有可能观测到膨胀磁效应. Under the simplified condition, the possible magnitude of the compressional magnetic effect is estimated, and it can be deduced that the change of the magnetic field before and after the earthquake is not necessarily caused by the compressive-magnetic effect in the non-magnetic anomalous zone. The formula introduced according to percolation current theory shows that the so-called expansion magnetic effect caused by the infiltration of groundwater is also very small, and it is possible to observe the expansion magnetic effect only if the infiltration area is large enough and groundwater is strenuous.