河北怀来ML4.4地震前的地热异常

2002年8月3日15时57分在河北怀来发生了ML4．4地震，在震中距100km范围内的4个台站，三马坊、赤城、矾山、张家口台数字化地热观测均有一定的异常反映，其中，三马坊、赤城台有较明显的临震异常。介绍了各台的地热观测情况，利用差分法、减组合滤波等非潮汐方法进行了分析，指出，该震例总结对今后的地震监测和预报有一定的借鉴和参考作用。

Geothermal Anomaly before Huailai, Hebei , Earthquake of ML4.4

An earthquake of M_L4.4 occurred in Huailai, Hebei, at 15:57,Aug. 3,2002.Some geothermal anomalies in digital observations turned up at 4 stations, Sanmafang, Chicheng, Fanshan and Zhangjiakou, which are all within 100km away from the epicenter of the earthquake, before the earthquake, especially at Sanmafang and Chicheng stations. In this paper the observations of the stations , and analysis by using some non-tide methods such as difference and reduced combination filtering etc. are introduced. This instance is helpful, in some degree, for earthquake monitoring and prediction in the future.