Velocity changes after the 2021 MS 6.4 Yangbi earthquake based on passive image interferometry

An M S 6.4 earthquake occurred in Yangbi, Yunan Province, China, on 21 May 2021. The epicenter was the blind branch fault west of Weixi–Qiaohou–Weishan fault, but no surface rupture obvious. In present study, continuous vertical component waveforms that were recorded six nearby permanent stations collected and noise cross-correlation autocorrelation techniques utilized to investigate velocity changes induced by Yangbi Earthquake. Velocity based single-station method reveal mainly coseismic declines, a maximum .09% EYA station. Results from technique show both positive negative changes, these lasted for approximately 3 months. volumetric strain generated Earthquake at depth 5 km exhibits an obvious four-quadrant distribution. Station pairs dilatation region (e.g., EYA–HEQ) display decrease velocity, whereas those contraction BAS–TUS, TUS–YUL, LUS–TUS) increase velocity. Based sensitivity scattered waves, obtained using involve highest weight coefficients near related two stations. Regarding one station pair different stress loading regions, static is nearest exerted greater impact change. observed are likely attributed combination near-surface physical damage changes. validation clock errors with magnitudes seconds effects measured also discussed.