A multidisciplinary study of the final episode of the Manda Hararo dyke sequence, Ethiopia, and implications for trends in volcanism during the rifting cycle
A multidisciplinary study of the final episode of the Manda Hararo dyke sequence, Ethiopia, and implications for trends in volcanism during the rifting cycle
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DOI：
10.1144/sp420.6
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发表时间：
2015-05
期刊：
影响因子：
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通讯作者：
T. Barnie;D. Keir;I. Hamling;B. Hofmann;M. Belachew;Simon Carn;David Eastwell;Jos Hammond;A. Ayele;Clive Oppenheimer;Tim J. Wright
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文献类型：
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作者：
T. Barnie;D. Keir;I. Hamling;B. Hofmann;M. Belachew;Simon Carn;David Eastwell;Jos Hammond;A. Ayele;Clive Oppenheimer;Tim J. Wright
摘要2005年至2010年期间在埃塞俄比亚Manda Hararo裂谷段的岩墙侵入序列为测试大陆裂谷的概念模型提供了机会。根据序列中直到岩墙13的趋势，预计如果岩浆供应继续，岩墙长度将缩短，随着伸展应力逐渐释放，喷发的规模将增加，距离段中心的距离将减少。在本文中，我们重新审视这些预测，提出了一个全面的概述2010年5月的堤坝和裂缝喷发，第14次和最后的序列，从干涉合成孔径雷达，地震活动，卫星热数据，紫外线SO2反演和多个激光雷达调查。我们发现的堤坝是比其他喷发的堤坝序列中，在两个方向上从段中心传播，但在其他方面相当典型的开放，传播速度和大地和地震矩。然而，虽然这次喷发距离板块中心更近，但规模比以往的事件要小得多。我们解释这表明，无论是曼达哈拉罗裂谷事件是岩浆有限的，或伸展应力变化的北部和南部的部分中心。
Abstract The sequence of dyke intrusions between 2005 and 2010 in the Manda Hararo rift segment, Ethiopia, provided an opportunity to test conceptual models of continental rifting. Based on trends up to dyke 13 in the sequence, it was anticipated that, should magma supply continue, dykes would shorten in length and eruptions would increase in size and decrease in distance from the segment centre as extensional stress was progressively released. In this paper we revisit these predictions by presenting a comprehensive overview of the May 2010 dyke and fissure eruption, the 14th and last in the sequence, from InSAR, seismicity, satellite thermal data, ultraviolet SO2 retrievals and multiple LiDAR surveys. We find the dyke is longer than other eruptive dykes in the sequence, propagating in two directions from the segment centre, but otherwise fairly typical in terms of opening, propagation speed and geodetic and seismic moment. However, though the eruption is located closer to the segment centre, it is much smaller than previous events. We interpret this as indicating that either the Manda Hararo rifting event was magma limited, or that extensional stress varies north and south of the segment centre.