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.

Sinabung火山位于苏门答腊岛Toba火山口北方边缘不到25英里处，自2013年11月以来一直在危险地喷发，对居住在周围Brestagi-Kabanjahe地区的10万人构成重大潜在危险。距东北25英里的棉兰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，Sinabung和Sibayak（其邻居）喷发的岩浆成分与Toba岩浆系统的共同点比Suantra的其他弧火山更多。不想危言耸听，这种对多巴的亲和力对我们应该如何看待来自锡纳朋和西巴亚克的危险有着明显的影响，因为类似多巴的成分往往会导致比正常的弧火山更具爆炸性的喷发。此外，如果这两座火山与多巴岩浆系统有某种联系，那么我们在预测潜在的危险时必须考虑到这一点。为了验证Sinabung-Sabayak和Toba岩浆系统之间联系的假设，这些研究人员建议寻找Toba？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，这将有助于他们确定任何多巴年龄的成分。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He结合起来。这将使他们能够通过Sinabung和Sibayak的活动历史来追踪Toba签名。此外，对锆石环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）重新熔化多巴的固化残余物和B）使老多巴岩浆恢复活力。这两种情况都将影响Sinabung和Sibayak的喷发风格，但后者意味着Toba信号是最近的，位于Sinabung和Sibayak之下。第二，多巴的化学指纹将使用整个岩石的主要和微量元素和同位素比率进行搜索。这项工作需要在RAPID的主持下及时完成，而铁可以说是热的，因为必须在爆炸性沉积物之前对最近的喷发进行采样，这些沉积物很小，被季风雨带走，失去了它们的背景。这项工作将与印度尼西亚同事和其他国际团体合作进行，以应对锡纳朋火山的危险。