Reconstruction of the eruptive history of Usu volcano, Hokkaido, Japan, inferred from petrological correlation between tephras and dome lavas
Reconstruction of the eruptive history of Usu volcano, Hokkaido, Japan, inferred from petrological correlation between tephras and dome lavas
复制标题
从火山灰岩与穹顶熔岩的岩石学关联推断日本北海道有珠火山喷发历史
DOI：
10.1111/iar.12301
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发表时间：
2019
期刊：
影响因子：
1.5
通讯作者：
Nakagawa Mitsuhiro
中科院分区：
文献类型：
--
作者：
Matsumoto Akiko;Nakagawa Mitsuhiro
乌苏火山自1663年以来已经喷发了9次。大多数喷发事件开始于爆炸性喷发，随后形成熔岩穹丘。然而，一些山顶熔岩圆顶和火山口的年龄仍然不确定。火山碎屑沉积物的岩石学特征从1663年到1853年爆发，已知的系统变化。在这项研究中，我们相关的熔岩与火山灰的假设下，熔岩和火山灰样品从同一事件将有相似的岩石学特征。虽然1663年的首次爆发并没有伴随着熔岩渗出，但熔岩穹丘或隐穹丘的形成与随后的爆发有关。我们推断的位置与每个事件相关的火山口的位置，从相关的熔岩圆顶和火山碎屑流存款分布，并发现，从17世纪末到19世纪的每一次喷发的活跃的排气口内的山顶破火山口的位置不同。此外，我们确定了一个以前未被识别的熔岩圆顶所产生的世纪末的喷发，这个圆顶在很大程度上被摧毁的爆炸性喷发在1822年，并取代了一个新的熔岩圆顶在后期的1822年事件在几乎相同的地方被摧毁的圆顶。这种对事件顺序的新解释与历史素描和文献是一致的。我们的研究结果表明，岩石学的相关性，加上地质证据，是有用的，不仅重建火山喷发序列，但也为洞察未来潜在的灾害。
Usu volcano has erupted nine times since 1663. Most eruptive events started with an explosive eruption, which was followed by the formation of lava domes. However, the ages of several summit lava domes and craters remain uncertain. The petrological features of tephra deposits erupted from 1663 to 1853 are known to change systematically. In this study, we correlated lavas with tephras under the assumption that lava and tephra samples from the same event would have similar petrological features. Although the initial explosive eruption in 1663 was not accompanied by lava effusion, lava dome or cryptodome formation was associated with subsequent explosive eruptions. We inferred the location of the vent associated with each event from the location of the associated lava dome and the pyroclastic flow deposit distribution and found that the position of the active vent within the summit caldera differed for each eruption from the late 17th through the 19th century. Moreover, we identified a previously unrecognized lava dome produced by a late 17th century eruption; this dome was largely destroyed by an explosive eruption in 1822 and was replaced by a new lava dome during a later stage of the 1822 event at nearly the same place as the destroyed dome. This new interpretation of the sequence of events is consistent with historical sketches and documents. Our results show that petrological correlation, together with geological evidence, is useful not only for reconstructing volcanic eruption sequences but also for gaining insight into future potential disasters.