中高频带地下水位对气压和固体潮的响应特征分析

我国前兆观测网络数字化改造的完成, 使得对地震地下水位观测的孕震信息提取和干扰因素排除的研究拓宽至更广的频率范围, 而对原有一些认识的重新考察也成为可能。 本文从中国地震前兆台网挑选出数据质量较好的10个台站, 分析各个台站2008年1月1日至5月11日的地下水位和气压资料及理论重力固体潮的频谱及其频域相关性特征, 并分析了地下水位对气压响应的时移。 结果表明, 中高频带地下水位对气压的响应没有低频带好, 两者相关性随周期的减小而减弱; 含水层岩性对中高频带地下水位的气压和固体潮响应特征有较大影响, 部分灰岩井在高频频段存在地下水位对气压响应异常的现象; 时移效应对水位的气压响应整体特征影响不大, 体现出两种信号自身的复杂性。

Response Characteristics of Groundwater Level to Barometric Pressure and Earth Tide in the Moderate to High Frequency Band

The completion of digital transformation of the precursor observation network in China has widened the frequency range for extracting related information of earthquake preparation and removing disturbance effects from groundwater, and make it possible for reviewing some of the previous knowledge. In this paper, we pick out 10 stations with high quality water level and barometric pressure data from the Center for Earthquake Precursory Observation Network of China, analyzed the spectrum characteristics and correlation of groundwater level, barometric pressure and earth tide of each station from Jan.1 to May 11, 2008, and discussed the time-lapse of groundwater to barometric pressure. It shows that the response of groundwater level to barometric pressure in moderate to high frequency band is not as good as that in the low frequency band and their correlation decreases with the decline of periods; and the lithologic characters of the well-aquifer systems has a great impact on the response characteristics of groundwater level to barometric pressure and earth tide in moderate to high frequency band. In several limestone wells, there exists abnormal response characteristics of groundwater level to barometric pressure in high frequency band. The time-lapse of groundwater level to barometric pressure has little effect on the overall response characteristics, reflecting the complexity of the two signals themselves.