Temporal Changes of Magmas That Caused Lava-Dome Eruptions of Haruna Volcano in the Past 45,000 Years

Yuki Suzuki*, Yurika Toeda, Shinya Kimura, Rei Tanaka

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We have studied four lava dome eruptions which occurred in 45–10 ka in Haruna volcano. Enclave parts (SiO2 50.9–55.1 wt%) and host parts (SiO2 59.5–64.5 wt%) in lava samples are all products of magma mixing. Characteristics of felsic end-member magmas are the same among four erup-tions, while those of mafic endmember magmas vary slightly in terms of bulk composition. The felsic magma had SiO2 ≥ 63 wt% and a temperature of 760°C–860°C, and contained ≥60 vol% of orthopy-roxene, amphibole, plagioclase, quartz, and Fe-Ti ox-ides. The mafic magma had SiO2 48–51 wt% and contained 0–10 vol% of olivine. The enclave magmas resulted from higher contribution of mafic magma and thus had higher temperature than the host mag-mas, which led to formation of enclave upon their interaction. Similarities of endmember magmas be-tween the four eruptions and the Futatsudake-Ikaho eruption (late 6th–beginning of 7th century) suggest structure of magma plumbing system and eruption triggering process have been basically unchanged in past 45,000 years. The felsic magmas were commonly mush-like and had high viscosity. Therefore, generation of low-viscosity magma through magma mix-ing, and vent-opening by the low-viscosity magma are mandatory for eruption to initiate. Unlike the Futatsudake-Ikaho eruption, the older four eruptions did not proceed to eruptive phase where felsic magma erupts without mixing and explosively. The absence of quartz only in felsic magma of Futatsudake-Ikaho eruption is consistent with its less-evolved bulk composition and slightly higher temperature than those of older four eruptions.

Original languageEnglish
Pages (from-to)694-715
Number of pages22
JournalJournal of Disaster Research
Issue number5
Publication statusPublished - 2022 Aug


  • Haruna volcano
  • enclave
  • lava dome
  • magma mixing
  • mush-like felsic magma

ASJC Scopus subject areas

  • Safety, Risk, Reliability and Quality
  • Engineering (miscellaneous)


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