Sinabung Volcano, Sumatra: Testing the link to the Toba Supervolcano

苏门答腊岛锡纳朋火山：测试与多巴超级火山的联系

• 批准号: 1445634
• 负责人: Shanaka de Silva
• 金额: $ 5万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1445634&HistoricalAwards=false
• 关键词: Sinabung; Volcano; Sumatra; Testing; link

Sinabung Volcano, located less than 25 miles from the northern edge of the Toba caldera, Sumatra, has been erupting dangerously since November, 2013 with significant potential hazard to the more the 100,000 people living in the surrounding Brestagi-Kabanjahe districts. 25 miles to the NE lies Medan, the capital of the North Sumatra province with over 2million people. Most concerning is that there is evidence that the erupted magma compositions of Sinabung and Sibayak (its neighbour) share more in common with the Toba magma system, than with other arc volcanoes in Suantra. Without trying to be alarmist, this affinity to Toba has obvious consequences for the way we should think about hazards from Sinabung and Sibayak as Toba-like compositions tend to result in more explosive eruptions that normal arc volcanoes. Moreover, if these two volcanoes are somehow linked to the Toba magma system, then we must factor that into predicting the potential hazard. To test the hypothesis of a link between Sinabung-Sabayak and Toba magma systems, these researchers propose to look for a Toba ?signal? in Sinabung and Sibayak. The signal will be in two parts. First, they will focus on microscopic zircon crystals and obtain age dates that will help them identify any Toba-aged components. They will do this by obtaining in-situ U-Th age determinations in zircons and then combining these data with He-in-zircon. This will allow them to track the Toba signature back through the history of activity at Sinabung and Sibayak through time. In addition, detailed analysis of zonation of zircons would allow them to differentiate between two alternative explanations for the Toba signal; a) re-melting solidified remnants of Toba and b) rejuvenating an old Toba magma. Both these scenarios will influence the eruptive style of Sinabung and Sibayak, but the latter would connote that the Toba signal is recent and beneath Sinabung and Sibayak. Second, the chemical fingerprint of Toba will be searched for using whole rock major and trace elements, and isotopic ratios The work needs to be done in a timely fashion under the auspices of RAPID, while the iron is hot so to speak, because the opportunity to sample the most recent eruption must be taken before the explosive deposits, which are small, are removed by monsoon rains and their context lost. This work will be done in collaboration with Indonesian colleagues and other international groups addressing volcanic hazards from Sinabung.

锡纳朋火山距离苏门答腊岛多巴火山口北缘不到 25 英里，自 2013 年 11 月以来一直在危险地喷发，对居住在布雷斯塔吉-卡班贾赫周边地区的 10 万多人造成了巨大的潜在危害。棉兰距东北 25 英里，是北苏门答腊省的首府，人口超过 200 万。最令人担忧的是，有证据表明，与苏安特拉的其他弧火山相比，锡纳朋和西巴亚克（其邻居）喷发的岩浆成分与多巴岩浆系统有更多共同点。无意危言耸听，这种与多巴火山的密切关系对我们如何看待锡纳朋火山和西巴亚克火山的危险产生了明显的影响，因为与多巴火山类似的成分往往会导致比正常弧火山更猛烈的喷发。此外，如果这两座火山与多巴岩浆系统有某种联系，那么我们必须将其纳入预测潜在危险的因素。为了检验锡纳朋-萨巴雅克和多巴岩浆系统之间存在联系的假设，这些研究人员建议寻找多巴“信号”。在锡纳朋和西巴亚克。信号将分为两部分。首先，他们将专注于微观锆石晶体并获得年龄日期，这将有助于他们识别任何多巴年龄的组件。他们将通过获得锆石中的原位 U-Th 年龄测定，然后将这些数据与锆石中的氦相结合来做到这一点。这将使他们能够通过锡纳朋和西巴亚克的活动历史追踪多巴签名。此外，对锆石分带的详细分析将使他们能够区分多巴信号的两种替代解释； a) 重新融化多巴凝固的残余物；b) 使古老的多巴岩浆恢复活力。这两种情况都会影响锡纳朋和西巴亚克的喷发方式，但后者意味着多巴信号是最近出现的，位于锡纳朋和西巴亚克下方。其次，将利用全岩主量元素、微量元素以及同位素比来寻找多巴的化学指纹。 这项工作需要在 RAPID 的支持下及时完成，可以说是趁热打铁，因为机会为了对最近的火山喷发进行采样，必须在季风降雨清除少量爆炸性沉积物并使其周围环境消失之前进行采集。这项工作将与印度尼西亚同事和其他解决锡纳朋火山灾害的国际组织合作完成。