Thermal Infrared Spectrum Property of Loaded Rock

摘要

The phenomenon of satellite thermal Infrared anomaly before earthquake has been reported since the late 1980s. The reported abnormal rise of surface temperatures reaches 2-4°C, and occasionally higher than that. Usually, the anomaly appears from one month to several days before the earthquake. To study the mechanisms of Infrared anomaly, some infrared radiation detection experiments for rock fracture were carried out. The experimental results showed that the TIR anomaly precursors appeared before the fracture of rock samples. However which bands are suitable for detecting the stress and fracture of rock by the thermal infrared equipment is an open question by now. In this paper, we subjected several blocks of granite to uniaxial deviatory stress up to failure. We measured the IR spectrum variation from the rock samples over the 3-15 μm range by the TurboFT infrared spectroradiometer. The experimental result showed that the radiation strength variations were different in various bands, the radiation strength variations in band 3.6-3.7 μm and 8.5-10μm were distinct along with the change of rock stress, but in other bands the radiation strength variations was not obvious or the relation between the infrared radiation and stress is not clear. It was possible to conclude that the bands 3.6-3.7 μm and 8.5-10 μm were the suitable bands for the detection of stress and fracture of rock.