Figure S3 . Examples of picking P -wave arrival times of a local earthquake recorded at the GLISN stations. The waveforms are filtered using a Butterworth filter with a frequency band of 1-10 Hz. The red dots denote the picked P -wave arrival times; gray bars denote theoretical arrival times calculated for the IASP91 model (Kennett & Engdahl, 1991). The epicenter (red star) and seismic stations (blue triangles) are shown on the inset map.