1975年2月4日,海城发生7.3级强烈地震。震前,孕震区出现了异常的增温现象和“地气”现象。在时间上,愈是接近地震发生,这些异常现象愈是明显。在地区上,它们大致分布于控制这次地震的北西西和北北东两条地质构造带的附近。但是,对这些事实与7.3级地震的发生是否有着直接的联系,还有待进一步深入探讨。 February 4, 1975, Haicheng 7.3 magnitude earthquake. Before the earthquake, there were abnormal warming phenomena and “geo-gas” phenomenon in the seismogenic zone. In time, the closer the earthquake occurs, the more obvious these anomalies. In the area, they are generally distributed in the vicinity of the two north-west and north-north east geological structures that control the earthquake. However, whether these facts are directly related to the occurrence of the 7.3-magnitude earthquake remains to be further explored.