Abstract: According to the M_S5.1 earthquake in Dengta, Liaoning Province on January 23, 2013, the variation of ATSCTF (Additional Tectonic Stress Caused by Tidal Force) at the epicenter (41.5°N, 123.2°E) was calculated for 5 weeks before the earthquake and 3 weeks after the earthquake (from December 16, 2012 to February 15, 2013) using the ATSCTF calculation model. When the earthquake occurred, the vertical component of ATSCTF was near the high phase point, indicating that tidal force had an inducing effect on the normal fault strike-slip earthquake. The low phase points of the ATSCTF cycle (December 19, January 4, January 18, February 2) were taken as the background, and the subsequent data of each cycle were subtracted from the background day by day. The variation of ATSCTF of the seismogenic period is C cycle. In space, the OLR of the epicenter and its southern area shows a significant continuous increase before the earthquake, and in time, it experiences an evolution process of initial micro-anomaly→anomaly strengthening→peak→attenuation→earthquake→quiet, which is consistent with the infrared radiation characteristics of the mechanical evolution process of rock stress loading-rupture: initial fretting rupture→expansion rupture→stress locking→earthquake outbreak→quiet. It shows that the tidal force has an inducing effect on the active fault in a critical state, and OLR is the radiation characterization of the seismic tectonic stress and strain process.

Key words: The 2013 Dengta M_S5.1 earthquake, Long-wave radiation, Tidal additional tectonic stress, ATSCTF period anomaly before earthquake