The Iwo-yama volcano of the Kirishima Volcanic Complex in Japan had a small phreatic eruption in April 2018, which newly formed multiple vents. The activity was recorded by two infrasound sensors and two monitoring cameras, which had been installed within 1 km of the vents. This study identified infrasonic signals from the multiple vents by a cross-correlation analysis between the two infrasound sensors. The analysis successfully revealed the signals from two main eruption craters and constrained the infrasound onsets at the individual vents in the two craters. We combined the infrasound results with the images from the cameras and reconstructed the sequence of the small phreatic eruption of Iwo-yama. At each of the two craters, the intense eruption, which was depicted by the evident infrasound signals, occurred several hours after the eruption onset. This study provides a sequence of the activities of the multiple vents in a phreatic eruption, which will be useful for understanding the phreatic eruption and hazard assessments.

中文翻译：

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次声互相关分析重建日本雾岛火山群硫磺山火山2018年小型潜水喷发序列

日本雾岛火山群的硫磺山火山于2018年4月发生小规模潜水喷发，新形成多个喷口。活动由安装在通风口 1 公里范围内的两个次声传感器和两个监控摄像机记录。这项研究通过两个次声传感器之间的互相关分析确定了来自多个喷口的次声信号。分析成功地揭示了来自两个主要火山口的信号，并限制了两个火山口各个喷口处的次声开始。我们将次声结果与摄像机图像相结合，重建了硫磺山小型潜水喷发的序列。在两个陨石坑中的每一个，明显的次声信号所描绘的强烈喷发，发生在喷发开始后几个小时。本研究提供了潜水喷发中多个喷口的活动序列，这将有助于了解潜水喷发和危害评估。