Fig. 1

Regional map showing the domestic seafloor cable route and the hypocenter distribution around Tonga. The purple line indicates the cable route; the section of cable used for hypocenter determinations from DAS data is shown in red. The red cross indicates the location where the cable was cut by the 2022 HTHH eruption and the orange square indicates where the cable was cut during post-eruption repair operations. Circles indicate hypocenters obtained from DAS observations in this study. The light blue and pink diamonds are locations of temporary and permanent onshore seismic stations, respectively. Red and blue triangles are onshore and ocean-bottom volcanoes, respectively (Global Volcanism Program 2023). The yellow arrow indicates the location of HTHH volcano. Bathymetry is from the ETOPO Global Relief Model (NOAA 2022)