Satellite observations of fumarole activity at Aluto volcano, Ethiopia: Implications for geothermal monitoring and volcanic hazard
Satellite observations of fumarole activity at Aluto volcano, Ethiopia: Implications for geothermal monitoring and volcanic hazard
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DOI：
10.1016/j.jvolgeores.2017.05.006
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发表时间：
2017-07-15
影响因子：
2.9
通讯作者：
Mather, Tamsin A.
中科院分区：
文献类型：
--
作者：
Braddock, Mathilde;Biggs, Juliet;Mather, Tamsin A.
富马拉腊是热液循环的地表表现形式，受岩浆、热液、水文和构造作用的影响。本研究调查了埃塞俄比亚主裂谷（MER）中一座不安分的火山Alanto的温度和空间范围的时间变化，以更好地了解对流体循环的控制以及岩浆和热液系统之间的相互作用。热红外（TIR）卫星图像，由先进的星载热发射和反射辐射计（ASTER）在2004年至2016年期间获得，用于生成时间序列的卫星温度和面积。ASTER图像中发现的热异常与已知的温度>80摄氏度的洞穴相吻合，位于断层结构上或附近，为上升的流体提供了通道。大多数的洞穴，包括那些沿着热液上涌的主要区域，Artu Jawe断层带的洞穴，像素综合温度变化仅为2 +/- 1.5摄氏度。例外的是位于假设的破火山口环断层上的Bobesa火山口，它显示出高达9摄氏度的像素集成温度变化，与热液系统对降水的延迟响应一致。我们的结论是，沿沿着主要断层的孔隙强烈耦合到岩浆热液系统，并随着时间的推移是相对稳定的，而那些沿着较浅的结构靠近裂谷侧翼的地下水流的季节性变化的影响更强烈。利用遥感数据监测卡多托火山的热活动，为了解这座活跃变形火山的行为作出了重要贡献。这种方法可以用于世界各地的其他火山监测和地热勘探。皇冠版权所有（C）2017由Elsevier B. V.发布。保留所有权利。
Fumaroles are the surface manifestation of hydrothermal circulation and can be influenced by magmatic, hydro thermal, hydrological and tectonic processes. This study investigates the temporal changes in fumarole temperatures and spatial extent on Aluto, a restless volcano in the Main Ethiopian Rift (MER), in order to better understand the controls on fluid circulation and the interaction between the magmatic and hydrothermal systems. Thermal infrared (TIR) satellite images, acquired by the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) over the period of 2004 to 2016, are used to generate time series of the fumarole temperatures and areas. The thermal anomalies identified in the ASTER images coincide with known fumaroles with temperatures >80 degrees C and are located on or close to fault structures, which provide a pathway for the rising fluids. Most of the fumaroles, including those along the major zone of hydrothermal upwelling, the Artu Jawe Fault Zone, have pixel-integrated temperature variations of only similar to 2 +/- 1.5 degrees C. The exception are the Bobesa fumaroles located on a hypothesised caldera ring fault which show pixel-integrated temperature changes of up to 9 degrees C consistent with a delayed response of the hydrothermal system to precipitation. We conclude that fumaroles along major faults are strongly coupled to the magmatic-hydrothermal system and are relatively stable with time, whereas those along shallower structures close to the rift flank are more strongly influenced by seasonal variations in groundwater flow. The use of remote sensing data to monitor the thermal activity of Aluto provides an important contribution towards understanding the behaviour of this actively deforming volcano. This method could be used at other volcanoes around the world for monitoring and geothermal exploration. Crown Copyright (C) 2017 Published by Elsevier B.V. All rights reserved.