ABSTRACT

The tectonic activity and rock fracturing will cause changes of strain and infrared radiation (IRR). Theoretically there exist certain relationships between strain and IRR in that they both are the results of stress activity of the crust. To obtain the relationships is the key to monitor tectonic activity and rock hazards, including geological hazards, earthquake and mine hazards and so on, by use of remote sensing technology.

In this paper two kinds of physical simulation experiments on IRR imaging detection and strain measure were carried out to reveal the relationships between strain field and IRR temperature field. In one of the experiments a disconnected-fault sample was used to simulate the activity of geological tectonic, while in another a hole-bored rock sample was used to simulate the fracturing process of rock tunnels. An infrared thermal imager was used to detect the changes of IRR, and a digital camera was used to monitor the visual light image. In order to obtain the strain fields of the loaded samples, the digital speckle correlation method (DSCM) was applied.

The experimental results showed that there are nice relationships between IRR temperature field and strain field. The IRR temperature increased in the position of compressing strain, while decreased in the position of tensile strain. With the spatial transferring of strain concentration the high IRR temperature spot transferred correspondingly. As the loaded samples get failure, some large strain strips appeared along the fracturing positions. If the fracturing is shear-resulted the IRR temperature of the strip increased, and if the fracturing is tensile-resulted the IRR temperature of the strip hardly changed. The results in this paper are meaningful for the remote sensing and early warning of rock fracturing, tectonic activity and earthquake.

1 INTRODUCTION

The tectonic activity and rock fracturing are two important phenomena in geosciences and rock engineering. Generally it will cause strain and infrared radiation (IRR) change. The thermal phenomenon or satellite thermal infrared (TIR) anomaly before earthquake (EQ) has been reported since 1980s (Gorny, 1988; Qiang, 1992; Tronin, 1996; Ouzounov, 2004; Arun, 2005). Meanwhile, some evidences of deformation anomaly before EQ were also reported (Matsu'ura, 1986; Subarya, 2006; Wang, 2006; Bo, 2007).

The IRR imaging detection experiments for loaded rock samples revealed that IRR anomaly variation was produced with rock deformation, fracturing and sliding (Geng, 1998; Wu, 2006a, 2006b). Theoretically the IRR temperature field is the representation of physical thermal field, and the strain field is related to the thermal field in that the two kinds of physical fields both are the results of stress activity. In order to reveal the relationships between thermal field and strain field in the tectonic activity and rock fracturing process, two kinds of physical simulation experiments on IRR imaging detection and strain measure were carried out.

2 EXPERIMENT DESIGN

In this paper a tortuously disconnected fault whose intersection angles be 30° was selected as the physical simulation model to study the variation features of IRR temperature field and strain field in the destabilization process of tectonic activity (see Fig. 1).

This content is only available via PDF.
You can access this article if you purchase or spend a download.