Plume height, duration and volume of sustained explosive eruptions inferred from eruption tremor amplitudes
Plume height, duration and volume of sustained explosive eruptions inferred from eruption tremor amplitudes
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从喷发震颤幅度推断出持续爆发性喷发的羽流高度、持续时间和体积
DOI：
10.1093/gji/ggac239
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发表时间：
2022
影响因子：
2.8
通讯作者：
Londono John Makario
中科院分区：
文献类型：
--
作者：
Mori Azusa;Kumagai Hiroyuki;Londono John Makario
通过使用持续爆炸性喷发产生的高频（5 - 10 Hz）震颤信号的振幅确定的震源振幅已被证明与喷发羽流高度呈幂律和指数关系，并与喷发体积通量呈比例关系。我们进一步研究了这些关系，并扩展了这种源量化方法，调查喷发持续时间通过使用包络线宽度，定义的累积源振幅的源振幅的比率。我们首先确认，源振幅和羽高度之间的关系，提出了以前的研究持有小爆发在内华达德尔鲁伊斯（哥伦比亚），虽然略有修改是必需的。然后，我们表明，包络线宽度与源振幅和累积源振幅的关系与亚普林尼期喷发在雾岛（日本）和通古拉瓦（厄瓜多尔）的喷发震颤可以用幂律来描述。这些地震的源振幅函数具有三个周期的特征，可以近似为梯形。幂律函数拟合的喷发量和喷发持续时间之间的关系，从这些关系是类似的估计，通过拟合幂律函数，以前报道的喷发量和持续时间的数据，有据可查的火山喷发和安山岩喷发。我们的研究结果表明，喷发持续时间可能会系统地改变喷发量时，管道是稳定开放的梯形源振幅函数的第二个时期。这项研究表明，源振幅可用于实时预测的羽流高度和喷发持续时间，这反过来又可用于估计灰降分布和火山灰运输当地居民和航空业务。
Seismic source amplitudes determined by using the amplitudes of high-frequency (5−10 Hz) tremor signals generated by sustained explosive eruptions have been shown to be related to eruption plume height by power-law and exponential relations and to eruption volume flux by a proportional relation. We further examined these relations and extended this source quantification approach to investigate eruption duration by using the envelope width, defined by the ratio of the cumulative source amplitude to the source amplitude. We first confirmed that the relationship between source amplitude and plume height proposed by a previous study holds for small eruptions at Nevado del Ruiz (Colombia), although slight modifications were required. We then showed that the relations of envelope width with source amplitude and with cumulative source amplitude of eruption tremor associated with sub-Plinian eruptions at Kirishima (Japan) and Tungurahua (Ecuador) could be described by a power law. The source amplitude functions of these tremors were characterized by three periods and could be approximated by a trapezoidal shape. A power-law function fitted to the relation between eruption volume and eruption duration obtained from these relations was similar to that estimated by fitting a power-law function to previously reported eruption volume and duration data of well-documented silicic and andesitic eruptions. Our results suggest that eruption duration may systematically vary with eruption volume when the conduit is stably open during the second period of the trapezoidal source amplitude function. This study demonstrated that source amplitudes can be used for real-time predictions of both plume height and eruption duration, which in turn may be used to estimate ashfall distributions and tephra transport for local residents and aviation operations.