The 2021 Semeru volcano eruption: An insight from visual, seismic, and deformation monitoring data

Abstract Semeru is the highest volcano on island of Java and one Indonesia’s volcanoes that has a potential threat pyroclastic flows. The eruption often shows transition pattern between explosive effusive styles. An increased eruptive activity occurred in 2021 with series explosions dominated first two thirds year then to flows December 2021. On 4 2021, dome collapse triggered significant reached maximum distance 16 km from crater resulted 51 casualties. In this paper, we aimed study dynamics magma movement depth surface assessing style eruptions visual, seismic deformation monitoring data. We analyzed data throughout volcanic system consists stations, 5 stations (2 tiltmeters 3 GPS stations), 2 Web Camera/CCTV. Our analysis indicates large were by excess pressure at shallow depths few hours before events. Deep earthquakes are relatively after lava or flows, possibly caused sudden decrease hydrostatic rock mass around pocket, thus triggering gas expansion. Deformation using tiltmeter Argosuko Jawar inflation deep source since 15 August Since 7 November measurement shown deflation patterns which indicate reservoir shallower reservoir. After 21 November, was observed again, indicating an increase supply pocket. results modeling vector period eruption, 1 – showed anomaly form volume > 1.7 about 0.84 million/m3. Between 31 flow, 8 km. addition, also 5.6 deflationary overpressure.