火砕堆積物の解析から探る火山噴火のダイナミクス  [in Japanese] Analyses of pyroclastic deposits as a tool for investigating the dynamics of volcanic eruptions  [in Japanese]

Access this Article

Search this Article

Author(s)

Abstract

噴出物の物質科学的研究の進展により,高分解能火山層序に基づいて過去の噴火を"観測"することが可能となりつつある.噴火様式の推移と,それに対応したマグマの火道上昇過程やマグマ溜まり内プロセスに関するケーススタディを増やすことは,規則性・普遍性を持つ噴火様式の推移パターンの発見につながり,噴火現象の分岐メカニズムに着目した"噴火メカニズム系統樹"の拡充に役立つ.研究方法で著しく進展した点として,石基マイクロライトの減圧結晶作用に基づくマグマ上昇プロセスの理解,揮発性成分のメルトへの溶解度の精密決定と,揮発性成分分析手法の高精度化による圧力スケールの読み取り精度の向上,浸透率測定データの蓄積やX線CT技術の発達などによる組織情報の活用などが挙げられる.これらによって,火山層序が特徴的に備える,噴火ダイナミクスの時間スケールと噴出物の体積に関する情報が,定量的に読み出されるようになってきた.

Recent progress in the science of the products of volcanic eruptions has made it possible to reconstruct past eruption processes on the basis of high-resolution volcanic stratigraphy. Case studies on changing eruption style and related conduit- and magma chamber-processes are helpful in establishing systematic, general patterns for the development of eruptions. They also contribute information towards an “eruption mechanism tree” that describes bifurcations in eruption processes according to the governing conditions. Methodological progress has been made on various aspects of eruptions, including our understanding of magma-ascent processes in relation to decompression-induced crystallization of groundmass microlites, precise determinations of volatile solubility in silicate melts, the development of analytical methods to measure volatile contents in glass and estimate magma pressure, the accumulation of permeability data, and advances in analytical techniques for rock microstructures (e.g., X-ray microtomography). Given these developments, we can retrieve information on the timescales of eruption dynamics and on the volume of erupted materials from the volcanic stratigraphy.

Journal

  • The Journal of the Geological Society of Japan

    The Journal of the Geological Society of Japan 117(6), 329-343, 2011

    The Geological Society of Japan

Cited by:  2

Codes

  • NII Article ID (NAID)
    130001271449
  • NII NACSIS-CAT ID (NCID)
    AN00141768
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    0016-7630
  • NDL Article ID
    11166665
  • NDL Source Classification
    ZM49(科学技術--地球科学--地質)
  • NDL Call No.
    Z15-174
  • Data Source
    CJPref  NDL  J-STAGE 
Page Top