Prediction of Magma Processes in the Early Eruptive Stage and Mitigation of Volcanic Hazards

早期喷发阶段岩浆过程预测与火山灾害缓解

• 批准号: 14380204
• 负责人: WATANABE Koichiro
• 金额: $ 8.06万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14380204/
• 关键词: Early Stage of eruption; Magma processes; Mount St.Helens; Juvenile material; Vesicular glass; Micro FTIR; Kuju Volcano; 噴火活動初期; セントヘレンズ火山; 発砲ガラス; 火山災害

Early phreatic eruptions may contain juvenile material that provide information about the ascending magma, and thus serve as precursors of impending magmatic eruptions. Samples of early tephra erupted in late March, 1980, from Mount St.Helens, were collected seven weeks before the lateral blast and climactic Plinian eruption that followed on May 18. Recently, sparse, vesicular glass shards that were found in these early tephra samples were reexawmined. Light density fractions from several samples of early tephra were concentrated with some fresh, microlite-poor vesicular glass shards detected in the tephra erupted in March 28 1980. The glass shards were then analyzed using electron microprobe analysis (EPMA) to obtain their chemical compositions for comparison to those of the pre-1980 tephra. Furthermore dehydration process of several shards during heating was measured using micro fourier transform infrared spectrophotometery (Micro-FTIR) to estimate the extent of hydration. Results of these experimentas follows;(1)The 1980 early tephra erupted from Mount St.Helens contained not only the material from the pre-1980 tephra layers (recycled material) but also juvenile material (although the amount was very small). (2)A half of vesicular glass shards in SH0328 are identified juvenile material with the remaining shards from pre 1980 tephra layers (mainly from P tephra). The shards from two different origins can be divided by difference of chemical composition. Juvenile vesicular glass shards could be distinguished from those derived from the pre-1980 tephra layers by difference of chemical composition. (3)Of the vesicular glass shards erupted from Mount. St.Helens, glass shards aged more than several ten thousands can be distinguished from those aged less than several thousands by dehydration curve. Thus, there is a possibility that direct participation of ascending magma could be predicted with this technique using tephra from earlier stages of eruptive activity.

早期的潜水喷发可能含有幼年物质，这些物质提供了关于上升岩浆的信息，因此可以作为即将到来的岩浆喷发的前兆。1980年3月下旬，圣海伦斯火山爆发了早期火山的样本，这些样本是在5月18日的侧向爆炸和普林尼火山高潮爆发前7周收集的。最近，在这些早期麻风样品中发现的稀疏的水疱状玻璃碎片被重新检查。在1980年3月28日爆发的火山中，我们用一些新鲜的、缺乏微晶石的囊状玻璃碎片对早期火山的几个样品进行了光密度分析。然后使用电子探针分析（EPMA）对玻璃碎片进行分析，以获得其化学成分，并与1980年前的tephra进行比较。利用微傅里叶变换红外分光光度法（micro - ftir）测量了几种薄片在加热过程中的脱水过程，以估计水化程度。实验结果如下：(1) 1980年圣海伦火山喷发的早期麻风层不仅含有1980年以前麻风层的物质（回收物质），还含有幼年物质（尽管数量很少）。(2) SH0328中泡状玻璃碎片有一半为幼年物质，其余碎片来自1980年以前的tephra层（主要来自P tephra层）。两种不同来源的碎片可以通过化学成分的不同来区分。幼年泡状玻璃碎片与1980年以前的玻璃碎片在化学成分上存在差异。(3)火山喷发出泡状玻璃碎片。在St.Helens，通过脱水曲线可以区分几万年以上的玻璃碎片和几千年以下的玻璃碎片。因此，利用这种技术，利用火山喷发早期阶段的热液，有可能预测上升岩浆的直接参与。

项目成果

Geological Monitoring of Volcanic Activity To Mitigate Volcanic Hazards

火山活动地质监测以减轻火山灾害

• 发表时间: 2005
• 期刊: Proc.2^<nd> Int.Symp.Earth Resources Eng. and Geological Eng.Education No.2
• 作者: Koichiro WATANABE;Koichiro WATANABE;Lucas Donny SETIJADJI;Lucas Donny SETIJADJI;Koichiro WATANABE;Koichiro WATANABE
• 通讯作者: Koichiro WATANABE

上川 真: "顕微FTIRによる火山ガラス微粒子の含水量測定と火山噴火活動モニタリングへの適用"自然災害研究協議会西部地区部会報・論文集. 27号. 55-58 (2003)

Makoto Kamikawa：“使用 FTIR 显微镜测量火山玻璃颗粒中的水含量及其在监测火山喷发活动中的应用”自然灾害研究委员会西区部门公告和论文第 27. 55-58 号（2003 年）。

Rdconstruction of Cenozoic Volcanic Centers in Jva Island(Indonesia) : A Key for Understanding the Geodynamic of Subduction Zone

印尼爪哇岛新生代火山中心的研究进展:了解俯冲带地球动力学的关键

• 发表时间: 2005
• 期刊: Proceedings of the 3rd International Workshop on Earth Science and Technology No.3.
• 作者: Koichiro WATANABE;Koichiro WATANABE;Lucas Donny SETIJADJI;Lucas Donny SETIJADJI
• 通讯作者: Lucas Donny SETIJADJI

On the Progress Design of Integrated Geologic Analysis System : Object-relational Database Model and Visualization for Earth

地球综合地质分析系统的进展设计：对象关系数据库模型与可视化

• 发表时间: 2005
• 期刊: Resource Geology Vol.55, No.3
• 作者: Y.Hatano;R.Hayakawa;K.Nishino;S.Ikeno;T.Nagasaka;T.Muroga;K.Watanabe;Lucas Donny SETIJADJI
• 通讯作者: Lucas Donny SETIJADJI

On the Progress Design of Integted Geologic Analysis System : Object-relational Detabase Model and Visualization for Earth Resources

综合地质分析系统的进展设计：地球资源对象关系数据库模型与可视化

• 发表时间: 2005
• 期刊: Resource Geology Vol.55,No.3
• 作者: Koichiro WATANABE;Koichiro WATANABE;Lucas Donny SETIJADJI
• 通讯作者: Lucas Donny SETIJADJI