Lava effusion rates from hand-held thermal infrared imagery: an example from the June 2003 effusive activity at Stromboli
Lava effusion rates from hand-held thermal infrared imagery: an example from the June 2003 effusive activity at Stromboli
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手持式热红外图像的熔岩喷出率：以 2003 年 6 月斯特龙博利火山喷发活动为例
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
L. Lodato
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作者：
A. Harris;Jonathan Dehn;M. Patrick;S. Calvari;M. Ripepe;L. Lodato
2003年6月，在斯特龙博利火山（意大利）开发了一种使用手持热图像数据计算熔岩渗出率的安全、简便和快速的方法。我们使用了前视红外辐射仪（FLIR），以获得图像的活动熔岩流场在2003年5月31日和6月16日之间的日常工作。在此期间，流场的几何形状和大小（通常几百米长的流位于陡峭的斜坡上）意味着整个流场的近垂直图像可以在直升机悬停时获得的单一图像中捕获，高度为750 m，距离海岸约101 km。我们使用这些图像，以适应热为基础的渗出率的方法，以前适用于低和高空间分辨率的卫星数据，允许自动提取渗出率的手持热红外图像。热导出（0.23-0.87 m3 s-1）和尺寸导出的渗出率（0.56 m3 s-1）之间的比较表明，热导出的范围集中在预期值上。在测量期间，平均渗出率为0.38±0.25 m3 s-1，这与1985-86年的喷出式喷发和正常（非喷出式）斯特龙博利活动计算的时间平均供应率相似。2003年6月3日，观测到一个短脉冲，峰值为1.2 m3 s−1。对这样一个峰值的一种解释是，由于中心柱中岩浆高度的增加，驱动压力增加。我们估计，这种脉冲将需要岩浆柱达到高于喷流口190米的高度，这大约是喷流口和NE火山口底部之间的高差。我们的方法给出了一个易于应用的方法，有可能提供高时间分辨率的渗出率时间序列。
A safe, easy and rapid method to calculate lava effusion rates using hand-held thermal image data was developed during June 2003 at Stromboli Volcano (Italy). We used a Forward Looking Infrared Radiometer (FLIR) to obtain images of the active lava flow field on a daily basis between May 31 and June 16, 2003. During this time the flow field geometry and size (where flows typically a few hundred meters long were emplaced on a steep slope) meant that near-vertical images of the whole flow field could be captured in a single image obtained from a helicopter hovering, at an altitude of 750 m and ∼1 km off shore. We used these images to adapt a thermally based effusion rate method, previously applied to low and high spatial resolution satellite data, to allow automated extraction of effusion rates from the hand-held thermal infrared imagery. A comparison between a thermally-derived (0.23–0.87 m3 s−1) and dimensionally-derived effusion rate (0.56 m3 s−1) showed that the thermally-derived range was centered on the expected value. Over the measurement period, the mean effusion rate was 0.38±0.25 m3 s−1, which is similar to that obtained during the 1985–86 effusive eruption and the time-averaged supply rate calculated for normal (non-effusive) Strombolian activity. A short effusive pulse, reaching a peak of ∼1.2 m3 s−1, was recorded on June 3, 2003. One explanation of such a peak would be an increase in driving pressure due to an increase in the height of the magma contained in the central column. We estimate that this pulse would require the magma column to attain a height of ∼190 m above the effusive vent, which is approximately the elevation difference between the vent and the floor of the NE crater. Our approach gives an easy-to-apply method that has the potential to provide effusion rate time series with a high temporal resolution.