大地震前后地温、降水及浅层热流通量场的结构特征
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摘要
利用中、蒙两国气象站的地温和降水资料，分析了近４０年来地温资料较密的华北及其北邻地区６次大地震前后的地温场及降水场的分布形势及其演变特征．在地震前半年到一年的时间里浅层地温场的演变特征是：未来震中区为正地温距平区，周围为较大范围的负距平带环绕，且正距平区呈逐渐增大增强的趋势，直至地震发生；降水场的特征是：震前１－５个月左右在大面积干旱的背景下，未来震中区同时存在一小范围的多雨中心．设计了一种利用浅层地温资料滤去来自上层大气的影响，获得浅层以下地热信息的方法．计算了能够反映深层地热信息的地表浅层热流通量，发现地震前地表以下存在着一个三维热柱结构，即中心热流向上，周围向下．
A typical distribution on soil temperature and precipitation field has been discovered round about strong earthquakes(MS≥7.0).A positive soil temperature anomaly area had kept in the coming epicentral area for a half to one year before the earthquake,meanwhile, a relatively large negative soil temperature anomaly belt had also surrounded it.Similarly,there was a small pluvial region in the coming epicentral area during the period of 1-5 months before the earthquake while the background was dry. The positive soil temperature anomaly area and the puvial region expanded and strengthened gradually as time went on.Based on the fact,a new method to calculate soil heat flux by using soil temperatuer data of meteorological stations was designed,which can filter the influence of atmosphere and get the information on geothermal field in deep earth.In this paper,the soil heat flux of about 200 stations round about each of six strong earthquakes (four in People's Republic of China,two in Mongolian People' s Republic) has been calculated,from which it can be seen that typical geothermal structure exists under the earth surface. The heat flux in the coming epicentral area is upward, aroud the area it is downward. The geothermal structure has some influences on soil temperature and precipitation field.
A typical distribution on soil temperature and precipitation field has been discovered round about strong earthquakes(MS≥7.0).A positive soil temperature anomaly area had kept in the coming epicentral area for a half to one year before the earthquake,meanwhile, a relatively large negative soil temperature anomaly belt had also surrounded it.Similarly,there was a small pluvial region in the coming epicentral area during the period of 1-5 months before the earthquake while the background was dry. The positive soil temperature anomaly area and the puvial region expanded and strengthened gradually as time went on.Based on the fact,a new method to calculate soil heat flux by using soil temperatuer data of meteorological stations was designed,which can filter the influence of atmosphere and get the information on geothermal field in deep earth.In this paper,the soil heat flux of about 200 stations round about each of six strong earthquakes (four in People's Republic of China,two in Mongolian People' s Republic) has been calculated,from which it can be seen that typical geothermal structure exists under the earth surface. The heat flux in the coming epicentral area is upward, aroud the area it is downward. The geothermal structure has some influences on soil temperature and precipitation field.
引文
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