2010年青海玉树7.1级地震能量场研究*
马禾青,杨明芝

(宁夏回族自治区地震局,宁夏 银川 750001)

能量场; 自然正交函数; 时间因子异常; 玉树7.1级地震

Research on the Energy Field about Yushu M7.1 Earthquake in Qinghai in 2010
MA He-qing,YANG Ming-zhi

(Earthquake Administration of Ningxia Hui Autonomous Region,Yinchuan 750001,Ningxia,China)

energy field; natural orthogonal function; time factor anomaly; Yushu M7.1 Earthquake in Qinghai

备注

采用自然正交函数展开方法,分析了2010年4月14日青海玉树7.1级地震前震中周围区域和沿玉树断裂带地震能量场的时间变化。结果 表明,青海玉树7.1级地震发生在高能量释放的背景上。震中周围区域几个主要典型场的时间因子以平稳变化为主要特征,但在地震发生前,主要典型场的时间因子出现明显的中短期异常变化,异常以尖点突跳为主要特点。第一个典型场的时间因子在震前3年出现大幅度异常,表现出相对于背景场能量增高的释放图像; 其余典型场异常则表现出突出的短临异常特征,出现在震前1～3月,表现为大幅度短期异常变化。可能表明地震活动结构的变化出现得较早,而临震时场的变化主要表现为扰动。沿玉树断裂带主要典型场时间因子异常均出现在震前2～3年,可能表明孕震区场的异常变化也会较早出现。典型场时间因子异常特征与以往关于能量场方面开展的工作所得结果类似。

Using the method of natural orthogonal function expansion,we analyzed the temporal variations of the seismic energy fields around the epicenter and along the Yushu Fault zone before Yushu M7.1 Earthquake,Qinghai on Apr.14 in 2010.The results showed that Yushu M7.1 earthquake in Qinghai occurred on the background of high energy release. The time factors of several primary typical fields around the epicenter mainly varied smoothly. However,in the main typical fields,these factors appeared abruptly in a short-and medium-term before the main shock,and curves of the factors were mainly featured by cusps and steps.The curve of time factors in the first typical field increased greatly in 3 years before the main shock,which showed that the energy release relative to energy increasing of the background field.And the curve of time factors in the rest typical fields showed the short-term anomaly in 1-3 months before the main shock. It was probably indicated that the changes of the seismic activity structure appeared early,but the changes of the fields mainly showed disturbance before the impending earthquake.The anomaly of time factor in primary typical fields along Yushu Fault Zone all appeared in 2-3 years before the main shock,which probably represented that the anomaly of the earthquake preparation area fields also appeared early.The abnormal features of the time factors of the typical fields were similar to the results about the energy fields in the former work.