爆破地震测试评价技术及一个典型实例

随着城市、村镇地域的扩展以及矿山采区的扩大，开采爆破与建筑物安全的矛盾常有发生。爆破地震测试及科学客观的影响评价，是调处类似矛盾的基础，具有现实的工程技术意义和社会意义。本文基于近年测震技术条件的进步，论述了爆破地震测试的技术方法和评价准则，并介绍了使用891-Ⅱ-16测震系统进行测试、评价的一个典型实例。     

近场震级起算函数确定与爆炸余震震级计算

在天然地震背景下，由于现有的起算函数在0—5km范围内是一个常数，因此，对于震源深度较浅的小地震震级的测定遇到了困难，本文通过理论计算和爆炸地震波实际测量两种方法，确定了近场0—5k瑚范围内的震级起算函数。用本文确定的震级起算函数计算了两次爆炸余震序列事件的震级，绝大多数的余震震级非常小，主要分布在-0．5—1．0级之间，余震序列的M-t图与一般强余震M-t图明显不同，它不仅存在反映较大震级的正向柱状线，而且还存在反映较小震级的负向短柱状线。     

A prediction model for frequency spectrum of blast‐induced seismic wave in viscoelastic medium

A prediction model for frequency spectrum of blast‐induced seismic waves is established. The effect of explosive sources is considered in this model. Our model implies that the frequency spectrum of blast‐induced seismic wave is mainly influenced by the initial pressure and the adiabatic exponent of explosives. The dominant frequency increases with the decreasing of initial pressure or the increasing of adiabatic exponent. In addition, this prediction model is verified by the experiment. The error of the dominant frequency is 4%–6%. It is indicated that the proposed model in this paper can reasonably predict the frequency spectrum of blast‐induced seismic waves, and then, we can provide a better frequency spectrum by optimizing the explosion source.     

2017年9月23日朝鲜振动事件记录特征分析

2017年9月23日16时29分在朝鲜丰溪里核试验场发生3.4级地震。本文基于中国地震台网对该地震事件的波形记录,分析认为:该事件不是一次简单的单独过程,虽然事件开始时发生爆破,但事件主体是由断层错动产生的天然地震。这次事件是爆破和天然地震相继发生的复合型事件。     

利用数字地震记录资料识别地震与爆破

利用西安数字地震遥测台网记录资料,通过对波形、P波与S波振幅比等方面进行对比分析,找出陕西及邻区地震与爆破的区别。     

小波变换方法及其应用

简要介绍小波变换的方法,并给出了小波变换在地震前兆和爆破识别等方面的一些应用,探讨二进小波分析在地震前兆研究方面的应用前景。     

矿山爆破中的电磁辐射

利用ＥＳＭＩ电磁干扰接收机和由多频天线与ＳＲ－５０Ｃ磁带机组成的记录系统,在不同距离观测到矿山爆破中的电磁辐射信号,不仅记录到与地震波同时出现的电磁辐射,还记录到大量震后电磁辐射信号．讨论了所得结果的性质及在地震预报中的意义．     

Calculation of Calibration Functions and Explosive Aftershock Magnitudes in the Near Field

The current calibration function used in calculating the magnitude of natural earthquakes within 5km is a constant; a fact that causes several serious difficulties for the calculation of the magnitude of small and shallow-focus earthquakes. According to the attenuation law of explosions and the propagation theory of elastic waves, the calibration function is calculated for near field quakes from 0kin to 5kin. Magnitudes of two aftershock sequences are calculated. The magnitudes of most explosion earthquakes are small, ranging mainly from magnitude -0.5 to 1.0. The M-t chart of the explosive aftershocks is completely different from that of strong earthquake aftershocks. It not only shows positive columnar lines indieatJng large magnitudes but also short negative columnar lines indicating small magnitudes.     

深圳职业技术学院高陡边坡工程爆破地震效应观测研究

介绍了深圳职业技术学院高陡边坡工程爆破地震效应观测选择的观测物理量及观测系统,概述了测点的布置及安全震动速度的选取,实测结果表明,跟踪监测并根据监测结果指导下一炮爆破参数整是确保安全的好方法。     

Explosion seismic P and S velocity and attenuation constraints on the lower crust of the North–Central Tibetan Plateau, and comparison with the Tethyan Himalayas: Implications on composition, mineralogy, temperature, and tectonic evolution

P and S velocity and attenuation estimates in the lower crust are obtained from a set of wide angle reflection–refraction profiles in the region of active tectonics at the NE edge of the Tibetan Plateau and discussed together with respect to similar data at its Himalaya–south Tibet edge.The quality factor is estimated in the lower half of the crust by accounting for the differential effect on amplitude–frequency observed between waves of different penetrations, and both in P and S modes. Attenuation values allow to exclude a significant proportion of partial melt and to estimate the homologous temperature, ratio of in situ to solidus absolute temperatures. The latter depend on the physical conditions being of dry, wet or dehydration melting, which are found different among the regions of the northern Bayan Har and northern Qang Tang boundaries between blocks, as well as the Tethyan–Himalayas, south of the Indus–Tsangpo suture. Their in situ temperatures differ also as estimated from their different V_p for a similar felsic composition.Joint measurement of several parameters, V_p, V_s, Q_p and Q_s reveals the composition, mineralogy, temperature and hydration conditions of the lower half of the thickened crust of Tibet that may be discussed in terms of evolution. The material presently in the thickened crust, even its lower part, has a felsic composition, upper to middle crustal lithology, and the temperature conditions estimated suggest that basic material that could have underlain it could be eclogitized and not appear anymore above the seismic Moho.Under northern Qang Tang, the felsic material in the lower half of the crust appears as hot and dry. Its burial may have occurred earlier or may have been moderate in the postcollisional phase. This is consistent with a model of indentation of the Qang Tang crust by an originally thinner Bayan Har crust to bring part of its crust to greater depth, suggested from imaging the crustal architecture. Under northern Bayan Har, the material in the lower half of the crust appears as felsic, at low temperature and not dry conditions. This is evidence that it has been transported from a shallower depth, and this recently enough not to be yet dehydrated and temperature equilibrated in a conductive geotherm. It supports a model of recent overriding of the middle crust of the north Kun Lun block to the north independently suggested from the image of crustal architecture. The Tethyan Himalayas case appears bracketed by these two cases in northern Tibet for V_p and temperature conditions, but shows highest attenuation in the lower crust that is colder but less dry than under northern Qang Tang.