Abstract
In this study, the authors has used the seismic tomography method to study the shallow seismicity of Sông Tranh 2 Hydropower Plant. The results show that:
1/ The P-wave velocity of the ST2 area of the lake and adjacent area varies from 5.90 km/s2 to ~6.10 km/s2 (Vp = 5.96 – 6.10); Vs = 3.50 to 3.60 km/s2 and Vp/Vs = 1.63 to 1.68.
2/ The focal depth of the earthquakes in the ST2 area of the lake reaches a maximum value of 10 km, mainly situated at the intersection of the faults: Rao Quan - A Luoi and Tra Bong - Tra My Faults, where the velocity ratio Vp / Vs = 1.63 to 1.67.