国外地震电磁现象观测

本文综合介绍了国外在地震电磁观测研究方面的进展和实例，结果显示地震电磁信号在地面和卫星观测记录中非常丰富.地面异常信号频带宽、分布范围广，时间上多集中于震前一个月或几天的时间段内出现.卫星地震电磁信号集中于ELE-VLF频段，时间上以震前几个小时为主，说明电磁信号具有明显的短临特性.我国地震电磁未来的发展方向应在现有的基础上，以超低频段为主，并发展地面与电磁卫星的三维立体联合观测，为地震短临预报服务.

Seismo-electromagnetic observation abroad

The progress and examples of seismo-electromagnetic observation abroad were introduced and summed up in detail.The results showed that,the electromagnetic signals were abundant in the observation whatever at surface or on satellites.The anomalous signals at surface were distributed in wide frequency bands and scopes,and occurred a month or several days before earthquakes.On satellites,seismo-electromagnetic signals concentrated at ELF-VLF bands,mainly occurring in a few hours before earthquakes,which all illustrated that electromagnetic signals are with apparent imminent feature.Based on present conditions,the future developing direction of seismo-electromagnetics in China should be on ultra-low frequency bands,and combine the observation at surface and satellites to build three dimensional observational system,serving for the imminent earthquake prediction.