*2.1. Data*

The earthquake data used in this research was obtained from the BMKG network of broadband stations in the form of waveform data from three-component seismograms (BHZ, BHN, and BHE) from 1 January 2010 to 31 December 2017. A total of 32 stations were used, covering the area 4.8◦ S–4.25◦ N and 120.5◦ E–134.5◦ E (Figures 1 and 2).

**Figure 2.** Arrival times distribution of P-and S-wave for all stations. Colored inverted triangles denote the number of phases per station.

Considering the distribution and locations of the regional stations, earthquakes with a magnitude ≥ 4 were chosen to facilitate the identification of P- and S-wave arrival times. A total of 1647 earthquake events have been recorded in the study area. Picking was performed manually to obtain P- and S-wave arrival times using SeisGram2K version 7.0 software [32]. P- and S-wave arrival times were determined in pairs at each station; the arrival times are clearly identified and recorded by at least four stations (Figure 3). The arrival times of a total of ~17,628 P-waves and ~17,628 S-waves were identified. The highest number of P- and S- phases were recorded in the southern part of the earthquake epicenter, while a smaller number of phases were recorded in the eastern part of Seram Island. The arrival times distribution for each station are shown in Figure 2, and its histogram in Figure S2.

**Figure 3.** Example of the 22 November 2017 event waveform from a three-component seismogram (BHZ, BHN, and BHE) which was picked using SeisGram2K version 7.0 software [32]. The blue, green, and red colors from each station represent the vertical component (BHZ), the north–south component (BHN), and the east–west component (BHE). From top to bottom, the recorded seismograms are shown at the KMSI, TMSI, GTOI, SMSI, SANI, TNTI, LBMI, and TOLI2 stations. The vertical P and S lines show the picked arrival times for P- and S-waves, while Ts-Tp is the time difference between the arrival times of the S- and P-waves.
