The long-term growth of volcanic edifices:: numerical modelling of the role of dyke intrusion and lava-flow emplacement
The long-term growth of volcanic edifices:: numerical modelling of the role of dyke intrusion and lava-flow emplacement
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DOI：
10.1016/s0377-0273(00)00257-2
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发表时间：
2001-03-01
影响因子：
2.9
通讯作者：
Provost, A
中科院分区：
文献类型：
--
作者：
Annen, C;Lénat, JF;Provost, A
野外观测和对活火山的监测证实了侵入复合体对火山生长的贡献。我们使用数值模拟来定量地估计与岩脉侵入有关的弹性位错和熔岩流积聚对火山生长的相对贡献。采用Okada （Bull）的方程计算了堤防侵入引起的地面隆升。Seismol, Soc。点。， 75(1985) 1135)。将熔岩流的扩散模拟为宾厄姆流体的流动。根据岩脉统计和熔岩流神学的实际参数，我们发现岩脉侵入对玄武岩盾构原型生长的贡献在体积上约为13%，在高度上约为30%。其结果在很大程度上取决于到达地表为熔岩流提供补给的岩脉的比例。对该模型的系统试验表明，如果岩脉厚而高，从一个小而浅的岩浆房发出，如果它们提供的熔岩行具有高屈服强度，则建筑物往往又高又陡。该模拟应用于Ko'olau （O'ahu ls）。（夏威夷）和Piton de la Fournaise（留尼旺岛）火山。根据Walker（地质学，14(1986)）描述的堤防参数对Ko'olau的模拟。幸存下来，巴氏教授。， 1350(1987) 961)和在夏威夷基拉韦厄火山（Kilauea volcano）收集的熔岩行特征相结合，形成了与真实火山非常接近的大厦形态。最适合的模型是Piton de la Fournaise中心锥的陡坡和东西向延伸，该模型是由一个非常小的浅岩浆房发出的10,000个短而厚的岩脉侵入而获得的，并且只提供了700个小体积熔岩流。同样的方法可以应用于玄武岩盾和其他火山类型在不同环境中的生长，包括非陆相火山作用。(C) 2001 Elsevier Science B.V.版权所有
The contribution of intrusive complexes to volcano growth is attested by field observations and by the monitoring of active volcanoes. We used numerical simulations to quantitatively estimate the relative contributions to volcano growth of elastic dislocations related to dyke intrusions and of the accumulation of lava flows. The ground uplift induced by dyke intrusions was calculated with the equations of Okada (Bull. Seismol, Soc. Am., 75 ( 1985) 1135). The spreading of lava flows was simulated as the flow of a Bingham fluid.With realistic parameters for dyke statistics and lava-flow theology we find the contribution of dyke intrusions to the growth of a basaltic shield archetype to be about 13% in terms of volume and 30% in terms of height. The result is strongly dependent on the proportion of dykes reaching the surface to feed a lava flow. Systematic tasting of the model indicates that edifices tend to be high and steep if dykes are thick and high, issued From a small and shallow magma chamber, and if they feed lava Rows of high yield strength.The simulation was applied to Ko'olau (O'ahu ls., Hawai'i) and Piton de la Fournaise (Reunion is.) volcanoes. The simulation of Ko'olau with dyke parameters as described by Walker (Geology. 14 (1986) 310, U.S. Geol. Surv, Prof. Pap., 1350 (1987) 961) and with lava-Row characteristics collected at Kilauea volcano (Hawai'i ls.) results in an edifice morphology very close to that of the real volcano. The best fit model of the Piton de la Fournaise central cone, with its steep slope and E-W elongation, is obtained by the intrusion of 10 000 short and thick dykes issued from a very small and shallow magma chamber and feeding only 700 low-volume lava flows. The same method may be applied to the growth of basaltic shields and other volcano types in different environments, including non-terrestrial volcanism. (C) 2001 Elsevier Science B.V. All rights reserved.