###### Abstract  
The Molucca Sea Plate, and Sangihe and Halmahera plates have a complex tectonic setting and interact to create the Molucca Sea Collision Zone. We re-picked 1647 events recorded from 2010 to 2017 from 32 of The Agency for Meteorology, Climatology, and Geophysics (BMKG) stations and obtained P- and S-arrivals of -17,628 phases. Hypocenter locations were determined using the software NonLinLoc. Then, we performed a travel time tomography in order to image the subsurface and approximate the Molucca Sea Plate subduction angle beneath Sulawesi's north arm, the relationship subduction zone and volcanic activity in Halmahera, and depth comparison of the Molucca Sea Plate. Our results show that (i) high Vp, high Vs, and low Vp/Vs are associated with the Molucca Sea Plate beneath Sulawesi's north arm, and the approximate subduction angle is -40 deg. (ii) Low Vp, low Vs, and high Vp/Vs beneath the northern and southern Halmahera Volcanic Arc are associated with a possible magma source. Volcanoes in the north have experienced eruptions and are dormant in the south. This group of volcanoes is connected by partial melting above the Molucca Sea Plate subducts to the east. (iii) High Vp, high Vs, and low Vp/Vs are interpreted as double subduction of the Molucca Sea Plate. It is submerged deeper in the north compared with the south, which is nearer to the surface. collision resulted in the formation of a high ridge in the middle of the two microplates, known as the Mayu-Talaud Ridge, which is characterized by intense, shallow earthquakes and an low gravity anomaly [3, 5, 7, 8]. The collision is \(\sim\)250 km apart [4] and convergently collides with the Molucca Sea Plate [4, 9] at a movement of 1.5 cm/yr [9]. The Molucca Sea Plate has an inverted U- or V-shape [2, 8, 10, 11, 12, 13] and has slab subducting to the west under the Sangihe Arc and subducts to the east under the Halmahera Arc. The subduction of the Molucca Sea Plate in both eastern and western directions makes for arc volcanisms in the Halmahera and Sangihe Arcs that run parallel to the subduction zone [8, 13, 14] with its two Wadati-Benioff Zone active of mantle earthquakes [4, 7, 10]. The collision of the Halmahera and Sangihe Arcs with the subduction of the Molucca Sea Plate remains active today [15, 16, 17, 18]. The Molucca Sea is one of the most seismically active areas in the world [19], as shown in Figure 1. There are many seismic zones in this area, such as the seismic zone concentrated in the central Molucca Sea at a depth of \(<\)60 km beneath the Mayu-Talaud Ridge, the seismic zone beneath the Sangihe and Halmahera Arcs, the seismic zone around the Gorontalo Basin, along the Minahasa peninsula, around MorotaI Island, the Sulawesi Sea, the Molucca-Sorong Fault, the Bacan-Sorong Fault, the Sulawesi slab in the northern part of Sulawesi's north arm, and the area around the Philippine slab in the eastern part of Halmahera Island. The red dots in Figure 1 indicate shallow earthquakes; these are mostly concentrated in the central Molucca Sea area beneath the Mayu-Talaud Ridge and the Gorontalo Basin; the brown dots indicate intermediate earthquakes that are mostly concentrated beneath the Sangihe and the Halmahera Arcs; the yellowish blue dots indicate deep earthquakes that are concentrated in the Sulawesi Sea area. Figure 1: The horizontal distribution of seismic map of the research location around the Molucca Collision Zone. SLW: Sulawesi island; ML: Molucca island; PA: Papua island; HLM: Halmahera island; SNA: Sulawesi’s north arm; SS: Sulawesi slab; PS: Philippine slab; HT and ST: Halmahera and Sangihe Trench; HA and SA: Halmahera and Sangihe volcanoes arc; CS: Celebes sea; MP: Minahassa peninsula; GB: Gorontalo Basin; MS: Molucca Sea; MTR: Mayu-Talaud Ridge; BSF, MSF, and SSF: Bacan, Molucca, and Sula Sorong Faults, respectively. Numerous studies on seismicity that relate to the structure and geometry of the Molucca Sea Plate have been carried out by previous researchers.