17:15 〜 19:15
[SVC30-P03] Temporal Variation of Eruption Mechanisms at Bromo Volcano: Insights from Componentry and Petrological Analysis
キーワード：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.
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.