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首页> 外文期刊>Journal of Volcanology and Geothermal Research2012V243-244NOCT,15 >Lava discharge rate estimates from thermal infrared satellite data for Pacaya Volcano during 2004-2010
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Lava discharge rate estimates from thermal infrared satellite data for Pacaya Volcano during 2004-2010

机译：根据2004-2010年Pacaya火山的热红外卫星数据估算的熔岩排放速率

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摘要

Pacaya is one of the most active volcanoes in Central America and has produced lava flows frequently since 1961. All effusive activity between 1961 and 2009 was confined by an arcuate collapse scarp surrounding the northern and eastern flanks. However, the recent breaching of this topographic barrier, and the eruption of a large lava flow outside of the main center of activity, have allowed lava to extend into nearby populated areas, indicating the need for assessment and monitoring of lava flow hazards. We investigated whether a commonly used satellite-based model could produce accurate lava discharge rates for the purpose of near-real-time assessment of hazards during future eruptions and to assess the dynamics of this persistently degassing system. The model assumes a linear relationship between active lava flow area and time-averaged discharge rate (TADR) via a simple conversion factor. We calculated the conversion factor via two methods: (1) best-fitting of satellite-derived flow areas to ground-based estimates of lava flow volume, and (2) theoretically via a parameterized model that takes into account the physical properties of the lava. To apply the latter method, we sampled four lava flows and measured density, vesicularity, crystal content, and major element composition. We found the best agreement of conversion factors in the eruption with the most complete satellite coverage, and used data for these flows to define the linear relationship between area and discharge rate. The physical properties of the sampled flows were essentially identical, so that any discrepancy between the two methods of calculating conversion factors must be due to modeling errors or environmental factors unaccounted for by the parameterized model. However, our best-fitting method provides a new means to set the conversion appropriately, and to obtain self-consistent TADRs. We identified two distinct types of effusive activity at Pacaya: Type 1 activity characterized by initially high TADRs of about 1-10 m~3·s~(-1) followed by a waning phase, and Type 2 activity characterized by low, scattered TADRs of about 0.1-1 m~3·s~(-1) The risk associated with Type 1 activity is much higher, so identifying the Type 1 radiance signature in satellite imagery is useful for monitoring an ongoing eruption.
机译：帕卡亚（Pacaya）是中美洲最活跃的火山之一，自1961年以来经常产生熔岩流。1961年至2009年之间的所有喷发性活动都被北部和东部两侧的弧形塌陷陡峭带限制。但是，最近突破了这一地形障碍，并且在主要活动中心之外爆发了大的熔岩流，这使得熔岩可以扩展到附近的人口稠密地区，这表明需要评估和监测熔岩流的危害。我们调查了常用的基于卫星的模型是否可以产生准确的熔岩排放速率，以用于近实时评估未来喷发期间的危害并评估该持续脱气系统的动态。该模型通过简单的转换因子假设活动熔岩流面积与时间平均流量（TADR）之间存在线性关系。我们通过两种方法计算了转换因子：（1）将卫星派生的流域与熔岩流的地面估算值进行最佳拟合，以及（2）理论上通过考虑熔岩物理特性的参数化模型。为了应用后一种方法，我们采样了四个熔岩流，并测量了密度，水泡性，晶体含量和主要元素组成。我们发现了喷发过程中转换因子与卫星覆盖范围最完全的一致性，并使用这些流的数据来定义面积与排放速率之间的线性关系。采样流的物理属性基本相同，因此两种计算转换因子的方法之间的任何差异都必须归因于参数化模型无法解释的建模误差或环境因素。但是，我们的最佳拟合方法提供了一种新方法，可以适当地设置转换并获得自洽的TADR。我们在木瓜树中发现了两种截然不同的流出性活动：第一类活动的特征是最初的高TADR约为1-10 m〜3·s〜（-1），随后是逐渐减弱的阶段；第二类活动的特征在于低TADR的分散性大约0.1-1 m〜3·s〜（-1）与1型活动相关的风险要高得多，因此在卫星图像中识别1型辐射特征对监测正在进行的喷发非常有用。

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    Hilary A. Morgan; Andrew J.L. Harris; Lucia Gurioli;

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    Department of Geological/Mining Engineering & Sciences, Michigan Technological University, 1400 Townsend Drive,Houghton, MI 49931, USA Laboratoire Magmas et Volcans, 5 rue Kessler, 63039 Clermont-Ferrand, France Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775 USA;

    Department of Geological/Mining Engineering & Sciences, Michigan Technological University, 1400 Townsend Drive,Houghton, MI 49931, USA Laboratoire Magmas et Volcans, 5 rue Kessler, 63039 Clermont-Ferrand, France Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775 USA;

    Department of Geological/Mining Engineering & Sciences, Michigan Technological University, 1400 Townsend Drive,Houghton, MI 49931, USA Laboratoire Magmas et Volcans, 5 rue Kessler, 63039 Clermont-Ferrand, France Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775 USA;

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  • 正文语种 eng
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  • 关键词

    Lava flow; Satellite; Thermal infrared; Time-averaged discharge rate; Pacaya;

    机译：熔岩流;卫星;热红外;时间平均放电率;帕卡亚;

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