How many explosive eruptions are missing from the geologic record? Analysis of the quaternary record of large magnitude explosive eruptions in Japan
How many explosive eruptions are missing from the geologic record? Analysis of the quaternary record of large magnitude explosive eruptions in Japan
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地质记录中遗漏了多少次爆炸性喷发？
DOI：
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发表时间：
2015
影响因子：
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通讯作者：
S. Takarada
中科院分区：
文献类型：
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作者：
K. Kiyosugi;C. Connor;R. S. Sparks;H. S. Crosweller;S. Brown;L. Siebert;Ting Wang;S. Takarada
日本的大规模爆炸性喷发被编入大规模爆炸性火山喷发（LaMEVE）数据库。在这里，我们使用这个数据集来调查日本爆炸性喷发的记录不足。我们确定了两个时间尺度上的火山爆炸性指数（VEI）4-5喷发的记录不足。模型拟合和Akaike的信息准则（AIC和AICc）模型选择表明，这些趋势可以用双指数衰减模型来表示，反映地质过程。与较小的喷发相比，较大喷发（VEI 6和7）记录率的时间序列显示出缓慢下降的趋势。这些时间序列可以用单指数衰减模型表示。遗漏喷发的百分比是根据拟合模型估计的。我们的研究结果表明VEI和漏报程度之间呈负相关，这表明在第四纪更大的VEI喷发是记录不足。例如，在100 ka、200 ka、300 ka和500 ka的记录中分别缺失了89%的VEI 4事件、65- 66%的VEI 5事件、46- 49%的VEI 6事件和36- 39%的VEI 7事件。日本和全球火山爆发频率的比较表明，全球数据库记录不足的情况是日本数据集的7.9-8.7倍。因此，在使用地质记录估计爆炸性喷发的复发率时必须考虑到事件记录不足的情况。
Large magnitude explosive eruptions in Japan were compiled for the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database. Here we use this dataset to investigate the under-recording of Japanese explosive eruptions. We identify under-recording of Volcanic Explosivity Index (VEI) 4–5 eruptions on two timescales. Model fitting and Akaike’s information criterion (AIC and AICc) model selection suggest that these trends can be represented with the double exponential decay model, reflecting geologic processes. The time series of the recording rate of larger eruptions (VEI 6 and 7) show a slowly decreasing trend in comparison to smaller eruptions. These time series can be represented with the single exponential decay model. The percentages of missing eruptions are estimated from the fitted models. Our results show an inverse correlation between VEI and degree of under-reporting suggesting that even larger VEI eruptions are under-recorded in the Quaternary. For example, 89 % of VEI 4 events, 65–66 % of VEI 5 events, 46–49 % of VEI 6 events and 36–39 % of VEI 7 events are missing from the record at 100 ka, 200 ka, 300 ka, and 500 ka, respectively. Comparison of frequencies of Japanese and global eruptions suggests that under-recording of the global database is 7.9–8.7 times larger than in the Japanese dataset. Therefore, under-recording of events must be taken into account in estimating recurrence rates of explosive eruptions using the geologic record.