Effective elastic thickness and mechanical anisotropy of South China and surrounding regions

摘要: Abstract South China and surrounding regions extend from the eastern Tibetan plateau, through tectonically stable Sichuan basin broad Mesozoic magmatic fold belt, to trench-arc-basin system in western Pacific which provide an ideal place study deformation of continental lithosphere under long-term magmatism oceanic subduction. We obtained effective elastic thickness ( T e ) its anisotropy analysis coherence between topography satellite gravity using wavelet methods. The values area vary 2 75 km, with relatively low (≤ 30 km) along tectonic boundaries, North–South Gravity Lineament (NSGL) seismic zones, high surface heat flow. evenly Lower Yangtze region Cathaysia block can be attributed long-lived subduction Paleo-Tethys Paleo-Pacific ocean basins beneath (SCB). NSGL SCB may separate unmodified (high thermally weakened (low due Despite different distances earthquakes occur more frequently 10–30 km, implying strain concentration low- regions. A positive correlation activity magnitude suggests that a highly anisotropic mechanical structure will promote localization brittle failure lithosphere. poor weak axis dynamic indicators present regime (the shear-wave splitting direction, maximum horizontal compressive stress direction) confirms mainly reflects inheritance