摘要:
根据ODP186航次的温度测井资料,对日本海沟地震断裂带进行研究。利用温度测井数据求取地温梯度,由放射性资料计算生热率,进而分析地震断裂带和温度以及生热率的关系。结果表明,在破裂带处由于冷却泥浆侵入影响,使得所测温度相对平衡地层状态偏低,在断裂带之上的地层地温梯度随深度衰减,在破裂带之下地层地温梯度随深度缓慢增加;在破裂带处,裂缝间含有黏土,含有的放射性元素比较高,因此,在破裂带比较多的地层生热率也会增大,反之亦然。总之,地温梯度在宏观上指示了断裂的分布范围,而生热率在微观上反映了破裂带的分布特征。
Abstract:
The ODP186 acquired temperature logging and other data from the Japan Trench seismic fault zone. We calculated the temperature gradient with temperature logging data, and the heat generation rate with radioactive data in order to understand the relation between the seismic fracture zone and the temperature and heat generation rate. Our results show that the measured temperature at the fracture zone is lower than the temperature in equilibrium condition, due to the cooling effect of mud circulation. And vice versa, the geothermal gradient attenuates with depth above the fracture zone, and increases slowly with depth beneath the fracture zone as expected.In the fracture zone, the heat generation rate is relatively high due to the high content of radioactive elements in the clay filled in the fractures. In this regard, the geothermal gradient could be used as a macroscopic indicator of fracture distribution range, and the heat generation rate reflects the microscopic distribution pattern of a fracture zone.
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