关键词: 高频微震活动, 超高频地震仪, 震源, 频谱特征

Abstract: Earthquake is a form of tectonic activity, an earthquake contains a lot of information, its frequency range is very wide. So far, the main frequency range of seismic records is below 100Hz, and the ultrahigh frequency seismic information got less attention by researchers. However, high frequency microseismicity can provide important information on micro-activities of fault. This paper introduces a new 100kHz ultrahigh frequency seismometer and its first application on high frequency microseismicity observation. The telemeter has been applied in Dali, Yunnan. Several high frequency microearthquakes were recorded and the corresponding earthquake location and spectral analysis were done. The results show that high frequency microearthquakes caused by crustal movement do exist and can be recorded by our telemeter. The recorded microearthquakes are of magnitudes between M_W=-3.0 and M_W=-1.0, maximum hypocentral distance up to 4.87km, dominant frequency ranging from 100Hz to 300Hz, and maximum frequency as high as 800Hz. It is possible that the ultrahigh frequency microseismicity observation(UFMO) will become a new approach to the study on the tectonic movement.

Key words: high frequency microseismicity, ultrahigh frequency seismometer, corresponding earthquake location, spectral analysis