Evaluation of Station Performance of the Indonesian Seismic Network Using the Primary Location Parameter

Abstract Indonesia’s tectonic setting has resulted in a high level of seismic activity, which makes seismic networks and early warning systems vital for this country. Indonesia’s seismic stations, a total of 411 stations in 2021, are maintained by the Meteorological, Climatological, and Geophysical Agency (BMKG). This study attempts to evaluate station performance, because these are crucial in monitoring seismic activity. We utilized information from the BMKG 2020 and 2019 seismic catalogs to analyze the performance of the stations. A total of 13,798 events were reported in 2019 with magnitudes (MLv) of up to 8, whereas 10,163 events with similar magnitudes were reported in 2020. Stations in the eastern part of Indonesia (Sulawesi, Lesser Sunda Islands, the Moluccas, and Papua) detected more events compared to stations in the western part of Indonesia (Borneo, Sumatra, and Java). Up to 1651 events were detected by a single station in eastern Indonesia, compared to 847 events in western Indonesia. BMKG stations in eastern Indonesia have recorded ample amounts of events, which is consistent with the high seismic activity found there. In terms of station coverage, events in the eastern part have better station coverage due to smaller azimuthal gaps, considering the geographic location. We also analyzed station performance and the number of recorded stations in terms of a function of time for each event in the Sumatra, Sulawesi, Lesser Sunda Islands, and Papua regions. Although the number of recordings obtained by stations was high after 15 s since the origin time, the azimuthal gap progression in Sumatra and Java remained large. Therefore, an additional ocean-bottom seismometer needs to be installed in the Sumatra–Java trench.