Volcanic edifice weakening via devolatilization reactions
Volcanic edifice weakening via devolatilization reactions
复制标题
DOI：
10.1111/j.1365-246x.2011.05097.x
复制
发表时间：
2011-09
影响因子：
2.8
通讯作者：
S. Mollo;S. Vinciguerra;G. Iezzi;A. Iarocci;P. Scarlato;M. Heap;Donald Bruce Dingwell
中科院分区：
文献类型：
--
作者：
S. Mollo;S. Vinciguerra;G. Iezzi;A. Iarocci;P. Scarlato;M. Heap;Donald Bruce Dingwell
火山不稳定性是一种基本的火山灾害，可能导致灾难性的侧翼坍塌。次火山基底可以鼓励这种不稳定性，特别是如果它容易受到机械弱化的挥发分反应接近岩浆温度。因此，了解代表性岩性的物理和化学性质如何在高温下恶化，对于减轻火山灾害可能具有高度相关性。对于沉积岩来说尤其如此，这种沉积岩通常位于世界各地的火山机构之下，即使在适度的温度下也会迅速恶化。因此，在这里，我们首次对包含次火山基底的沉积岩进行了由岩浆温度引起的脱挥发分反应的实验研究。我们的研究结果表明，泥灰质石灰岩代表的Mt埃特纳，脱挥发分反应，即粘土矿物的脱羟基和碳酸钙的脱碳，导致机械强度和地震速度的显着降低。这些温度驱动的反应可以在比先前估计的低得多的应力下促进火山不稳定。
SUMMARY Edifice instability, that can result in catastrophic flank collapse, is a fundamental volcanic hazard. The subvolcanic basement can encourage such instability, especially if it is susceptible to mechanical weakening by devolatilization reactions near magmatic temperatures. For this reason, understanding how the physical and chemical properties of representative lithologies deteriorate at high temperatures is potentially highly relevant for volcanic hazard mitigation. This is particularly true for sedimentary rock, commonly found underlying volcanic edifices worldwide, that undergo rapid deterioration even under modest temperatures. Therefore, here we present the first experimental study of devolatilization reactions, induced by magmatic temperatures, on sedimentary rock comprising a subvolcanic basement. Our results show that, for a marly limestone representative of the basement at Mt Etna, devolatilization reactions, namely the dehydroxylation of clay minerals and the decarbonation of calcium carbonate, result in a dramatic reduction of mechanical strength and seismic velocities. These temperature-driven reactions can promote volcanic instability at stresses much lower than previously estimated.