Overbank block-and-ash flow deposits and the impact of valley-derived, unconfined flows on populated areas at Merapi volcano, Java, Indonesia
Overbank block-and-ash flow deposits and the impact of valley-derived, unconfined flows on populated areas at Merapi volcano, Java, Indonesia
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印度尼西亚爪哇默拉皮火山溢流块和火山灰流沉积物以及源自山谷的无约束水流对人口稠密地区的影响
DOI：
10.1007/s11069-011-0044-x
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发表时间：
2011
期刊：
影响因子：
3.7
通讯作者：
K. Preece
中科院分区：
文献类型：
--
作者：
R. Gertisser;N. Cassidy;S. Charbonnier;L. Nuzzo;K. Preece
默拉皮火山是中爪哇的一座安山质火山复合体，是印度尼西亚最频繁爆发的火山之一，对周围100多万人口构成永久威胁。由于频繁的火山活动，自16世纪中期以来报告的60次左右的火山爆发造成了约7，000人死亡，并摧毁了该地区的许多村庄。2006年6月，一次火山爆发几乎在世纪以来第一次影响到火山南翼和东南翼人口稠密地区。由此产生的块状和火山灰流沿着一个切割的河谷（Kali Gendol）向下移动到距离源头7公里的地方，在四个主要地点从主河道中冲出。生成了无限制（漫滩）生物放大系数，覆盖了主河谷两侧的河间区域以及Kaliadem村的被掩埋建筑物和其他基础设施特征，Kaliadem村位于根多尔河谷西岸，距离默拉皮山顶约5公里。使用传统的火山学领域为基础的方法和非侵入性，高分辨率的地面穿透雷达技术，这些漫滩沉积物的形态和内部结构进行了详细研究，以评估这些流动在当地的破坏性影响。结果表明，水流动力学和存款结构的复杂的，局部规模的变化是显而易见的，生物曝气生物滤池能够运输大量的大型块（>1-2米）的山谷范围。我们提出了一个概念模型，这些渠道化的BAF到Kaliadem的河间阶地逃逸，并显示，通过火山南侧的村庄和邻近地区的火山碎屑岩序列的地层分析，该地区已反复受到影响的漫滩BAF和爆炸性喷发在过去的几个100年（和更多）。
Merapi, an andesitic volcanic complex in Central Java, is one of the most frequently erupting volcanoes in Indonesia and poses a permanent threat to the surrounding population of over 1 million people. With frequently recurring volcanic activity, the sixty or so reported eruptions since the mid-1500s have caused ~7,000 fatalities and destroyed numerous villages in the region. In June 2006, an eruption affected the densely populated area on the volcano’s southern and south-eastern flanks for the first time in almost a century. The resultant block-and-ash flows (BAFs) travelled down an incised river valley (Kali Gendol) to a distance of 7 km from the source, breaking out of the main channel at four main locations. Unconfined (overbank) BAFs were generated, which covered the interfluve regions on either side of the main valley and buried buildings and other infrastructure features in the village of Kaliadem, situated on the western bank of the Gendol valley ~5 km from the summit of Merapi. Using traditional volcanological field-based methods and non-invasive, high-resolution ground-penetrating radar techniques, the morphology and internal architecture of these overbank deposits were studied in detail in order to evaluate the destructive impact of these flows in a local context. The results show that complex, local-scale variations in flow dynamics and deposit architectures are apparent and that BAFs are capable of transporting significant numbers of large blocks (>1–2 m) out of the valley confines. We propose a conceptual model for the escape of these channelised BAFs onto the interfluvial terrace at Kaliadem and show, through a stratigraphic analysis of the pyroclastic successions underlying the village and adjacent areas on the volcano’s southern flank, that the area has been affected repeatedly by overbank BAFs and explosive eruptions over the past few 100 years (and more).