Lithological control on shear-wave velocity anisotropy in core samples from the Taiwan Chelungpu Fault Drilling Project

► Shear wave birefringence (SWB) is measured in TCDP siltstone and sandstone samples. ► SWB in siltstone is low (∼3.5%) and controlled by low angle bedding dip. ► SWB in sandstone is higher (∼15%) and due to a network of vertical microcracks. ► Microstructural characteristics are sufficient to account for SWB measured at larger scale.