华北地区矿山爆破活动的时空特征

Spatio-temporal characteristics of mine blast activity in North China

矿山爆破作为地震信号源具有经济方便的优点,但作为企业行为,有其自身的活动特性.华北地区矿产资源丰富,矿山爆破活动频繁.为有效利用这些爆破开展地震学研究,基于北京数字遥测地震台网2006年1月至2010年12月的爆破事件目录,分析了华北地区的爆破活动特征.该区的爆破活动在空间上分布广泛,但爆破密度和强度不均.对地震学研究有较大意义的ML≥2.0的爆破,有3条较为明显的分布带:三河-迁安带、房山-行唐-平鲁带和涞源-大同带.矿山爆破作为高危险的生产活动,受到多种因素的影响.爆破活动在2006年和2007年较为活跃,但在2008年爆破次数急剧减少,2009年和2010年又逐渐增加.爆破活动的季节性不是很明显,但2月和10月,爆破活动相对较少.天尺度的爆破活动水平变化不大.在小时尺度上,爆破活动具有显著的分布特征:在12时～13时,爆破活动最为密集;17时～20时,爆破活动也较为活跃.在爆破的地震动效应方面,清楚记录爆破信号的地震台站个数,即有效记录数,对于相同震级的爆破,存在很大差异,但其最大值与爆破震级基本成正比.依据这些特征,可更好地对华北地区大当量的矿山爆破进行有针对性的地震学观测.

Mine blasts can be used as an economical and convenient type of seismic sources. However,as commercial conduct, the mine blast has its own activity manners, which are important for effectual seismological observations of large blast events. In this paper, we make a statistical analysis of mine blasts between January 2006 and December 2010 in North China, based on the non-earthquake catalogs by Beijing Digital telemetry Seismic Network. Their spatial distribution is wide, but not uniform in density and intensity. Concerned with blasts with magnitude Mc 2. 0, there are three obvious belts including Sanhe-Qian＇ an, Fangshan-Xingtang-Pinglu and Laiyuan-Datong. The blasting activity is affected by many factors for its economic and risky properties, and varies remarkably at the annual scale. It maintains a quite high level in 2006 and 2007, but sharply reduces in 2008, and then gradually increases until 2010. The blasting seasonality is not very strong. Relatively, the activity is low in February and October. The daily distribution of blast shows no distinct variations but the hourly one shows obvious rush hours. Its highest peak for each year consistently occurs between 12 and 13 o＇ clock, and the secondary active time interval is from 17 to 20 o＇clock. As for the seismic effect induced by mine blasts, the number of available seismic records from an event varies much for the same magnitude. Its maximum is basically proportionate to the latter. The blasting activity characteristics can be used as a guide to the seismological observation of large mine blasts in North China.