A simple explanation for the space-based calculation of lava eruption rates
A simple explanation for the space-based calculation of lava eruption rates
复制标题
熔岩喷发率天基计算的简单解释
DOI：
10.1016/s0012-821x(01)00443-5
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发表时间：
2001
影响因子：
5.3
通讯作者：
D. Rothery
中科院分区：
文献类型：
--
作者：
R. Wright;S. Blake;A. Harris;D. Rothery
了解玄武岩喷发过程中熔岩渗出率的变化，在试图提供有关熔岩将流动多远的初步预测时，可能具有重要意义。然而，在使用传统的基于场的技术精确地确定渗出率方面存在问题。为了改善这个问题，Harris等人[J. Geophys. 102（1997），7985-8003; Bull. Volcanol. 59（1997），49-64; J. Volcanol.地热。Res. 102（2000），237-269]开发了一种利用红外卫星数据确定渗出率的方法，并说明了该方法如何可用于提供渗出率的实际估计，在基拉韦厄（夏威夷）、Krafla（冰岛）、埃特纳和Stromboli（意大利）的几次喷发期间反复进行。Harris等人[J. Geophys. 102（1997），7985-8003; Bull. Volcanol. 59（1997），49-64]表明，他们的方法允许通过将活动熔岩流（从卫星数据导出）损失的热量等同于熔岩冷却物质释放的热量来计算瞬时熔岩渗出率。本文的目的是提供一个更简单的替代解释。我们发现，而不是被用来计算热损失，哈里斯等人。102（1997），7985-8003; Bull. Volcanol. 59（1997），49-64; J. Volcanol.地热。Res. 102（2000），237-269]实际上使用卫星数据来估计在数据采集移动时卫星视场内存在的活动熔岩的面积。因此，它们呈现的渗出率的变化只能与该区域的变化成比例。然后将活动流动面积乘以一个常数，该常数的值是从熔岩流热平衡的粗略近似值中获得的。重要的是，该项的绝对值福尔斯落在Pieri和Baloga [J. Volcanol.地热。Res. 30（1986），29 -45]来解释34个历史夏威夷熔岩流的喷发率（即时间平均的渗出率）和熔岩流面积之间的强线性相关性。结果表明，Harris等[J. Geophys. Res. 102（1997），7985-8003]并不产生瞬时渗出率，而是提供了一种有效且有用的方法来根据流动面积的测量来估计平均渗出率（即，喷发率）。
Knowing how lava effusion rates vary during basaltic eruptions can be of great significance when trying to provide preliminary forecasts regarding how far lava will flow. However, problems exist in accurately determining effusion rates using conventional field-based techniques. To ameliorate this problem Harris et al. [J. Geophys. Res. 102 (1997), 7985–8003; Bull. Volcanol. 59 (1997), 49–64; J. Volcanol. Geotherm. Res. 102 (2000), 237–269] developed a method for determining effusion rates using infrared satellite data, and showed how the method could be used to provide realistic estimates of effusion rates, repeatedly during several eruptions at Kilauea (Hawai’i) Krafla (Iceland), Etna and Stromboli (Italy). Harris et al. [J. Geophys. Res. 102 (1997), 7985–8003; Bull. Volcanol. 59 (1997), 49–64] indicate that their method allows instantaneous lava effusion rates to be determined thermodynamically by equating the amount of heat lost by an active lava flow (derived from the satellite data) to the amount of heat liberated by the cooling mass of lava. The purpose of this paper is to provide a simpler, alternative explanation. We find that rather than being used to calculate heat loss, Harris et al. [J. Geophys. Res. 102 (1997), 7985–8003; Bull. Volcanol. 59 (1997), 49–64; J. Volcanol. Geotherm. Res. 102 (2000), 237–269] actually use the satellite data to estimate the area of active lava present within the satellite’s field of view at the movement of data acquisition. Thus, changes in the effusion rates they present can only be proportional to changes in this area. The active flow areas were then multiplied by a constant, the value of which is obtained from a crude approximation of the lava flows heat balance. Crucially, the absolute value of this term falls within the range of an empirically derived parameter that was found by Pieri and Baloga [J. Volcanol. Geotherm. Res. 30 (1986),29–45] to explain strong linear correlations between eruption rate (i.e. the time-averaged effusion rate) and lava flow area for 34 historic Hawaiian flows. As a result, we find that the method of Harris et al. [J. Geophys. Res. 102 (1997), 7985–8003] does not yield instantaneous effusion rates, but instead provides a valid and useful way to estimate average effusion rates (i.e. the eruption rate) from measurements of flow area.