汶川地震前后水位频谱特征分析

以频谱分析方法作为理论基础,采用周期图法计算汶川地震前后距震中500 km以内10口观测井水位（包括动水位与静水位）的功率谱,对比分析2009年无大震年份同时期的数据,研究结果表明：水位的频域特征受制于观测井的地质构造背景、观测方式和观测深度;水位的波动能量主要集中于大于4天与小于0.5天周期,震后水位波动能量则集中在大于8天的周期;动水位频谱更加丰富.另外,不同井水位的频域响应特征与该井观测层岩性有关,需进一步研究.

Analysis about the spectrum characteristics of water level before and after Wenchuan earthquake

In this study, based on the spectrum analysis theory, the power spectrum of 10 stations, which close to the epicenter of the earthquake （〈500 km）, include both hydrostatic level and dynamic water level is calculated with periodogram method. Comparing the result calcu- lated in the same way depended the data in 2009, we could find that.①The spectrum feature of water level is controlled by geological structure, observation method and depth; ②The power of the fluctuation concentrate on the period longer than 4d and shorter than 0.5 d, but focus on longer than 8 d after the earthquake; ③The power of dynamic water level fluctua- tion is richer among all periods than that of hydrostatic level. In addition, the spectrum fea ture of various stations also is related to its hydrological geology surrounding, and the rela- tionship is remain need more study.