Radiative heat power at Stromboli volcano during 2000-2011: Twelve years of MODIS observations
Radiative heat power at Stromboli volcano during 2000-2011: Twelve years of MODIS observations
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DOI：
10.1016/j.jvolgeores.2011.12.001
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发表时间：
2012-02-15
影响因子：
2.9
通讯作者：
Ripepe, M.
中科院分区：
文献类型：
--
作者：
Coppola, D.;Piscopo, D.;Ripepe, M.
12年的夜间MODIS（中分辨率成像光谱仪）观测，已被分析，以检测和量化的Stromboli火山（2000年3月至2011年9月）发出的辐射热功率。使用精确的背景扣除的中分辨率成像光谱仪信号在下午4时，我们能够区分两个主要制度的热辐射，有关不同程度的火山活动。喷发（发生在2002年12月28日和2007年2月27日）的平均辐射量约为186兆瓦，警报检测频率为50- 95%。相反，在典型的斯特龙博利活动期间，平均辐射功率约为9兆瓦，警报探测频率为0- 45%。虽然在喷溢喷发期间，辐射功率基本上受熔岩排放速率的控制，我们的研究结果表明，在非渗出期，（strombolian制度）的强度和频率的中分辨率成像光谱仪警报控制的高度的岩浆柱喂养的活动在表面上。特别是，我们发现，类似于50兆瓦的辐射功率对应于高岩浆柱，该岩浆柱在喷口区域以与斯特龙博利供给系统内通常供应更深的富含气体的岩浆相同的速率（类似于0.3米（3）秒（-1））暴露。在这种情况下，岩浆系统接近稳态区。在这个阈值以上，可能会发生从斯特龙博利过渡到溢出制度，如检测到类似的50兆瓦，8-10天前的最后两个主要的侧翼喷发。这些值是在辐射功率逐渐增加1-2个月后达到的，这可能与管道最浅部分内岩浆柱的上升有关。此外，我们的数据表明，在2000年至2011年期间，岩浆柱发生了几次上升和下降的周期，然而，这些周期并没有最终导致喷涌式喷发，而只是反复出现持续的飞溅或喷泉和山顶溢流。这些波动的频率和强度大大增加后，2007年的喷发，从而表明，这一事件在某种程度上扰乱了Stromboli.We强调，检测到的辐射功率高于50兆瓦的浅层管道系统是一个非常高的岩浆柱，这可能预示着一个溢出式喷发和/或持续的喷口活动期间的发作的明确证据。总之，我们建议，系统的MODIS数据分析，可以用来检测Strombolian活动的强度变化，并可能大大提高在Stromboli火山监测，以及在其他开放系统的火山。(C)2011 Elsevier B. V.保留所有权利。
Twelve years of night-time MODIS (Moderate Resolution Imaging Spectroradiometer) observations, has been analysed to detect and quantify the radiative heat power emitted by Stromboli volcano (from March 2000 to September 2011). Using an accurate background subtraction of the MODIS signal at 4 pm, we were able to discriminate two main regimes of thermal radiation, related to different levels of volcanic activity. Effusive eruptions (occurred on December 28, 2002 and February 27, 2007) radiated at an average of similar to 186 MW with a frequency of alert detection of 50-95%. Conversely, during the typical strombolian activity, an average of similar to 9 MW is radiated, with a frequency of alert detection of 0-45%.Although during the effusive eruptions the radiative power is basically controlled by the lava discharge rate, our results suggest that during non-effusive periods (strombolian regime) both the intensity and the frequency of MODIS alerts are controlled by the height of the magmatic column feeding the activity at the surface. In particular we found that a radiative power of similar to 50 MW corresponds to a high magma column which is exposed, in the vent area, at the same rate in which the deeper gas-rich magma is typically supplied within the feeding system of Stromboli (similar to 0.3 m(3) s(-1)). In this condition the magmatic system approaches steady state regimes. Above this threshold a transition from strombolian to effusive regimes may occur as shown by the detection of similar to 50 MW, 8-10 days before the onset of both the last two major flank eruptions. These values were reached after 1-2 months of gradual increase of the radiative power which was likely associated the rising of the magma column within the shallowest portion of the conduit. In addition our data suggest that over the years 2000-2011 several cycles of rise and fall of the magma column have occurred, which however did not culminate into an effusive eruption but only into recurrent episodes of sustained spattering or fountaining and summit overflows. These fluctuations has substantially increased in frequency and intensity after the 2007 eruption thus suggesting that this event has perturbed in some way the shallow plumbing system of Stromboli.We stress that the detection of a radiative power higher than 50 MW is a clear evidence of a very high magma column, which may prelude the onset of an effusive eruption and/or periods of sustained vent activity. In conclusion, we suggest that systematic analysis of MODIS data can be used to detect variations in the intensity of strombolian activity and may considerably improve volcano surveillance at Stromboli, as well as at other open-system volcanoes. (C) 2011 Elsevier B.V. All rights reserved.