Japan Geoscience Union Meeting 2025

Presentation information

[E] Poster

S (Solid Earth Sciences ) » S-VC Volcanology

[S-VC30] International Volcanology

Wed. May 28, 2025 5:15 PM - 7:15 PM Poster Hall (Exhibition Hall 7&8, Makuhari Messe)

convener:Chris Conway(Geological Survey of Japan, AIST), Keiko Matsumoto(Geological Survey of Japan, The National Institute of Advanced Industrial Science and Technology), Taishi Yamada(Sakurajima Volcano Research Center, Disaster Prevention Research Institute, Kyoto University), Masataka Kawaguchi(Earthquake Research Institute, the University of Tokyo)


5:15 PM - 7:15 PM

[SVC30-P03] Temporal Variation of Eruption Mechanisms at Bromo Volcano: Insights from Componentry and Petrological Analysis

*Aisyah Qurrataaini1, Tsukasa Ohba1, Jananda Nuralam Indriyanto2, Takashi Hoshide1 (1.Akita University, 2.Institut Teknologi Bandung)


Keywords:Bromo, Componentry, Eruption Mechanism, Petrology

Understanding the temporal evolution of eruption mechanisms is crucial for interpreting volcanic behavior and assessing hazards. This study investigates variations in eruption style at Bromo volcano through integrated componentry and petrological observations of recent volcanic ash deposits.

The volcanic ash comprises three primary components: juvenile, lithic, and crystal particles. Variations in lithic (wallrock fragments), juvenile, and crystal content reflect distinct eruptive processes. Elevated lithic proportions signal conduit erosion or vent-clearing phases, where pre-existing crustal material is incorporated into the eruption column. Dominant juvenile components, characterized by blocky morphologies, point to magmatic fragmentation driven by volatile exsolution and gas expansion within ascending magma. Conversely, high crystal abundances suggest prolonged magma residence times in subsurface reservoirs, allowing for partial crystallization prior to eruption.

These compositional shifts underscore dynamic changes in eruption mechanisms. These changes suggest fluctuations in ascent dynamics and degassing-driven fragmentation processes. Additionally, evidence of water-magma interactions may indicate shifts in eruption intensity over time. These findings highlight the complex interplay between magma physicochemical properties and eruption mechanisms, providing valuable insights into Bromo’s eruption dynamics and potential precursors for future activity.