【摘要】 中国南北地震带南段位于青藏高原东南缘，是中国大陆地震活动频繁的地区。本文根据NGDC-720地磁场模型，计算并分析了中国南北地震带南段地壳磁异常分布特征，重点分析了1970年以来6级以上地震及其余震分布区的地壳磁异常垂直分量?Z和磁偏角?D的分布特点。结果显示地震主要分布在磁异常为负值或强弱过渡区，磁偏角?D分量最明显。利用磁异常计算居里点等温面，并与大地热流相结合揭示地壳热结构特点，发现高地热区和强震活动区相对应。研究区的居里面深度在20.8 km-31 km之间，起伏分明，隆起区与大地热流高值区相一致。大多数强震的震源深度小于居里点深度，主要集中在脆性状态的中上地壳。强地震主要发生在居里面深浅过渡带。上述结果可作为该区强震预测的参考依据。更多还原

【Abstract】 The south segment of the China North-South Seismic Belt is located in the southeast margin of the Qinghai Tibet Plateau.This region is characterized by the frequent seismic activity in Chinese mainland.In this paper,the geomagnetic field model NGDC-720 and the data of terrestrial heat flow are used to investigate the distribution of crustal magnetic anomalies,the depth of Curie surface,and the characteristics of the crustal thermal structure in the south segment of the North-South Seismic Belt.The distribution characteristics of the vertical component △Z and the magnetic declination △D in the area with earthquakes over a magnitude of 6 and their aftershocks since 1970 are focused on.The results show that the earthquakes are mainly observed in the area of negative magnetic anomaly or the strong and weak transition zone.It especially shows in the △D.The Curie surface in the study area varies significantly,ranging from 20.8 to 31 km.The uplift area of the Curie surface is consistent with the high-value area of terrestrial heat flow.The high geothermal area corresponds to the strong earthquake activity area.The focal depth of most strong earthquakes is shallower than the depth of the Curie surface.The strong earthquakes mainly occur in the deep-shallow transition zones of the Curie surface.The results can be used as a reference for strong earthquake prediction in this area.更多还原