## 5 Conclusions
We use this damping value to achieve a good compromise between data variance and model variance for the inversion, both the real data and the checkerboard test; Figure S6: Vertical cross-section of Derivative Weight Sum (DWS) on profile South-North: A-A', B-B' and profile West-East: C-C', D-D'. The DWS is used to find the number of ray paths that pass through a grid node. The first column is the Vp value, and the second column is Vp/Vs value (logarithmic scale). The black color is the high-resolution zone, and the red triangle is the volcanoes; Figure S7: Vertical cross-section of Ray Hit Count (RHC) on profile South-North: A-A', B-B' and profile West-East: C-C', D-D' for making a thorough cut in a particular DWS. The first column is the Vp value, and the second column is Vp/Vs value (logarithmic scale). The black color is the high-resolution zone, and the red triangle is the volcanoes; Figure S8: Vertical cross-section of Diagonal Resolution Element (DRE) on profile South-North: A-A', B-B' and profile West-East: C-C', D-D' which concerning matrix resolution of R (damped least-squares problems), with an R-value between 0 and 1. The first column is the Vp value, and the second column is Vp/Vs value. The black color is the high-resolution zone, and the red triangle is the volcanoes; Figure S9: The distribution frequency estimated error location. (A-C) are the x, y, and z directions; Figure S10: The distribution between the number of events and the azimuthal gap; Figure S11: The distribution between P- and S-travel times and epicentral distance; Figure S12: Histogram of travel time residual (black and yellow bars color are initial and final travel time residual, respectively). The mean travel time residual decreased from \(-1.111\) s to 0.156 s. The Binwidth histogram is 0.2 s; Figure S13: The curve between the number of iterations and weighted RMS residual. Tomography inversion became convergent after 15 iterations, and the weighted RMS residual decreased by approximately 47%; Figure S14: Histogram of RMS Residual (initial: yellow bars color and final: black bars color). The mean of RMS residual decreased by approximately 33%. The Binwidth histogram is 0.1 s; Figure S15: The horizontal section of CRT profiles from a depth of 0 to 330 km. The purple dashed line is an area that is good well-resolved. The blue color indicates positive perturbations, and the red color indicates negative perturbations relative to the initial model. The first column is Vp perturbation, and the second column is Vp/Vs perturbation; Figure S16: Horizontal tomographic inversion results for Vp, Vs, dan Vp/Vs ratio from a depth of 0 to 330 km. The bright area is an area that good well-resolved, and the blurred area is an area that was not well-resolved; Table S1: The highest value of Vp and Vp/Vs for the DWS, RHC, and DRE resolution tests. **Author Contributions:** Conceptualization, G.R., B.J.S., A.D.N. and S.R. ([PERSON]); methodology, G.R., A.D.N., B.J.S. and S.R. ([PERSON]); software, G.R., S.R. ([PERSON]), P.S., M.R., A.A., F.M. and H.A. ; validation, G.R., A.D.N., S.R. ([PERSON]) and F.M. ; formal analysis, G.R., A.D.N., B.J.S. and S.R. ([PERSON]); investigation, A.D.N., B.J.S., S.R. ([PERSON]) and S.R. ([PERSON]); resources, G.R., A.D.N., B.J.S., S.R. ([PERSON]), S.S. and S.R. ([PERSON]); data curation, G.R., A.D.N. and S.R. ([PERSON]); writing--original draft preparation, G.R. and F.M. ; writing--review and editing, A.D.N., S.R. ([PERSON]), Z.Z., D.P.S. and S.S.; visualization, G.R., F.M., A.A. and H.A. ; supervision, A.D.N., S.R. ([PERSON]), Z.Z., D.P.S. and S.S.; project administration, G.R. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by BUDI-DN Ministry of Research, Technology and Higher Education (Kemristekdikti) in collaboration with the Indonesian Endowment Fund for Education (LPDP) Number: PRJ-5440/LPDP.3/2016; Addendum Number: PRJ-193/LPDP.4/2019. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable.