磁铁矿热电效应:地震地电异常的新模式  

THE THERMOELECTRIC EEFFECT OF MAGNETITE:A NEW MODEL FOR ABNORMAL GEO-ELECTRICITY FROM THE FORMATION AND OCCURRENCE OF EARTHQUAKE

作　　者：申俊峰[1] 申旭辉[2] 刘倩[1] 

机构地区：[1]中国地质大学(北京)地质过程与矿产资源国家重点实验室,北京100083 [2]中国地震局地震预测研究所,北京100036

出　　处：《矿物岩石》2010年第4期21-27,共7页Mineralogy and Petrology

基　　金：国家科技支撑计划(2008BAC35B05);国家自然科学基金重大研究计划(90914002)

摘　　要：采用BHTE-06新型热电测量仪,选择地壳内广泛分布的磁铁矿进行热电性测量,结果表明:磁铁矿的热电导型均为N型,其热电系数σ(单位温差下热电势增量)近似恒值,为-0.05mV/℃,标准偏差1.15,这说明磁铁矿为电子型半导体并具有稳定的热电转换效能。通过不同成因磁铁矿对比测量,以及固定和不固定结晶学方向的对比测量还可知,磁铁矿的热电性不受其成因和结晶学方向的制约,说明磁铁矿聚集体能够将热电效应叠加放大。因此认为,地壳中的磁铁矿聚集体可能是地震过程中将热能转换为电能的热-电转换器,热电效应可能是导致地震地电场异常的原因之一,即地震地电异常存在热电机制。依据测试所得的热电系数σ值,按照热电和地电基本理论进行的电场模拟计算表明:由磁铁矿热电效应引起的热电场强度能够达到-n×10-6V/m～-n×10-4V/m,该电场强度足以引起地表电场的显著异常,因而是地震地电异常的重要模式之一。The magnetite,exist widely in crust,was tested on thermoelectricity by new equipment of BHET-06.The results showed that the electric-conduction of all magnetite samples are N-type（also called electron type）,and thermoelectric coefficient σ（thermal voltage was divided by temperature difference）is a constant value of-0.05 mV/℃ approximately,with the standard deviation is 1.15.It means that the thermal energy can be converted steady into electric energy by magnetite.Furthermore,results by compared test for different genetic magnetite under fixed and unfixed position showed that the thermoelectricity of magnetite is not controlled by genesis and crystallography direction.This implied that the thermoelectric effect of the magnetite can be piled up and made much stronger.For this reason,a new viewpoint is proposed that the magnetite aggregate in the crust is maybe a converter from thermal into electric during process of earthquake occurrence,namely,thermoelectric effect may be one of reasons on abnormal geo-electricity during earthquake,or abnormal geo-electricity in earthquake is caused by thermoelectric mechanism.Based on the thermoelectric coefficient value tested in the experiments,and on the thermoelectric and geo-electric theories,the thermoelectric field was computed.It was showed that the field intensity can reach-n×10-6 V/m～-n×10-4 V/m.Obviously,the field values are large enough to lead to the geo-electric abnormity.So it is considered that thermoelectric effect is a new model for the abnormal geo-electricity during the earthquake process.

关 键 词：磁铁矿 热电效应 地震 地电异常 

分 类 号：P511.2[天文地球—地质学] P571