Analysis on Source Process of Strong Earthquakes in Qinghai Province Based on Broadband Data

Four earthquakes with M > 6.0 occurred in Qinghai Province, China froth 1988 to 1990. Using broadband data from GDSN, the source ruptures of these earthquakes and tectonic surroundings were studied using waveform modelling combined with background data of geological tectonics. Through the analysis of apparent source time function (aSTF) and apparent time difference (aTD), the complexity of sources was discussed, and in view of source analysis, the result further supports the conclusion that the compressive stress axis of tectonic stress field in northeastern Qinghai-Xizang (Tibetan) plateau is at the NE direction, is nearly horizontal, turns counter-clockwise to the NEE or N to S direction, and is nearly horizontal close to the northern Qinghai-Xizang plateau.