张北6.2级地震地温短临异常特征

THE FEATURES OF GEOTEMPERATURE IN SHORT TERM PRECURSORY ANOMALIES BEFORE THE ZHANGBEI EARTHQUAKE WITH M S 6.2

张北地震前４０天左右，在距该震中１００～２００ｋｍ的河北阳原三马坊、北京塔院和延庆五里营地温测点先后出现典型地温短临异常，异常幅度为０．００１～０．０１℃，据此作了一定程度的预报。在震级和震中距相近的条件下，三马坊测点在张北地震前的地温异常变化幅度仅为大同┐阳高地震前的１／１０，这可能与构造条件有关。在该地震的映震范围内有前兆反应的地温测点所占比例为２７％。

Some typical short term precursory anomalies of the geotemperature have been observed about 40 days before the Zhangbei earthquake at the Sanmafang station, Yangyuan county, Hebei Province, as well as at Tayuan station in Beijing and Wuliying station, Yanqing county about 100～200 km away from the epicenter. Based on those observations, the prediction has been made to a certain extent. The change amplitude of the geotemperature anomaly before the Zhangbei earthquake is only one tenth of that before the Datong Yanggao earthquake at the Sanmafang station, though both the magnitude and epicentral distance are similar. It may be related to the tectonic setting. It should be pointed out that the number of the geotemperature stations where the precursory anomalies appeared is 27 percent of the total earthquake response stations.