【摘要】 基于地震波能量,利用数字地震波形资料,提出地震力标度σ值定量预测指标,详细介绍了σ值计算方法,研究了强震前σ值时间和空间变化规律。结果表明:①地震力标度σ值与震级ML存在lgσ=0.98ML+6.93标度关系,σ值是一个表征地震时震源处断层平均驱动力的物理量,其大小介于地震频度和能量之间;②云南地区σ值会出现类似于正弦波的高低起伏周期变化,发生于波峰附近的强震绝大多数以连发的形式发生,而波谷附近则以单个地震发生为主,以σ值曲线从谷底上升1.5个月为起报时间点,则3个月及其以内发生强震的可能性为78%;③σ值空间分布表明,主震前2～4个月σ值在较大范围内会出现高值异常,随着主震的临近,σ高值会向未来主震震中及附近迁移、集中和收缩,主震发生前很短时间(1个月内),σ值会迅速变小,临震前地震活动异常平静现象明显。更多还原

【Abstract】 Based on seismic wave energy,using digital seismic waveform data,we present a quantitative predicttion index called seismic force scale σ value.We first introduced the method of calculating the σ value in detail,and then studied the variation of σ values in time and space before strong earthquakes.The results show:① The relationship between σ values and magnitude ML follows lgσ=0.98ML+6.93,and σ is a physical quantity that characterizes the average driving force of fault in earthquake source,with size between the earthquake frequency and energy;② In the Yunnan area,σ values appeared cyclic similar to the sine wave.Earthquake occurred in the vicinity of peak most occurred in the form of repeating,but mainly in the form of single earthquake around the trough.Taking the point 1.5 months from the bottom up in the σ value curve as forecast time,then the possibility of strong earthquakes is 78% within 3 months;③ High-value anomaly in σ values appeared 2~4 months before the main shock in the larger region.With the approach of the main shock,high σ values will move,concentrate and contract to the area of future main shock and the surrounding area,and σ values will be rapidly getting smaller a short period of time before the main shock(within 1 month),with obvious quiecence of seismicity.更多还原