大同-阳高地震地热异常与机理初探

A STUDY ON THE GEOTHERMAL ANOMALY AND OF THE DATONG-YANGGAO EARTHQUAKE

摘要:

1989年10月大同-阳高地震前后,距震中约75km的三马坊地热测点的高精度地温观测仪器(分辨率0.0001℃),记录到持续50多天、温度上升幅度达0.15℃的明显的地热异常。本文研究了该异常变化的特点。在总体上,异常为幂函数型升温形态。在地震发生前几天,地热异常呈现"相对下降-下降速率变缓-急剧回升-短时平稳-地震发生"的过程。本文还对地热异常的机理进行了初步探讨。

Abstract:

Before and after the Datong-Yanggao earthquake in October 1989, a high precision ther-mometer (resolution 0.0001℃) installed at the Sanmafang Ooservatory, which is about 75 km from the epicenter, recorded a significant geothermal anomaly. The amplitude of the anomaly is 0.15℃ and the duration time is over 50 days. This paper discusses the characteristics of the abnormal temperature variation. As a whole, the variation has a shape of increasing temperature with a type of the power function, and is a temperature effect due to the fault creeping caused by the increase of regional stress field. Several days before the earthquake, the geothermal precursory anomaly showed a process that is, "declining-decline rate slowing down-sharply rising-short-term stableness-an earthquake occurring". The mechanism of the geothermal anomaly is also studied, preliminarily.