Evidence for magmatic underplating and partial melt beneath the Canary Islands derived using teleseismic receiver functions
Evidence for magmatic underplating and partial melt beneath the Canary Islands derived using teleseismic receiver functions
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DOI：
10.1016/j.pepi.2012.09.004
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发表时间：
2012-12-01
影响因子：
2.3
通讯作者：
Ibanez, J. M.
中科院分区：
文献类型：
--
作者：
Lodge, A.;Nippress, S. E. J.;Ibanez, J. M.
近年来，越来越多的研究集中在解决海洋岛屿火山的内部结构。传统上，活源地震实验已被用来成像火山机构。在这里，我们使用来自地震事件的压缩到剪切（P到S）转换的地震相位的分析来呈现结果，所述地震相位由参与主动源实验“TOM-TEIDEVS”的台站记录（Ibanez等人，2008年），在特内里费岛，加那利群岛。我们使用扩展时间多锥频域互相关估计方法（Helffrich，2006），对来自加那利群岛兰萨罗特岛和拉帕尔马岛的地震记录进行接收函数（RF）分析，以补充这些数据。我们使用Sambridge（1999 a，B）的邻近反演方法来模拟RF，我们的结果表明所有三个岛屿下方都存在岩浆底侵作用，范围从2到8 km，但与岛屿的年龄没有明显的相关性。在拉帕尔马和特内里费岛之下，我们发现了局部低速区（LVZ），我们将其解释为部分融化，并与历史地震（拉帕尔马）和最近地震（特内里费岛）的位置相关。对于兰萨罗特岛，我们没有对最近的火山活动区进行采样，也没有发现LVZ的证据。相反，我们发现一个简单的梯度速度结构，在类似的4，10和18公里的深度，与以前的研究不连续。(C)2012 Elsevier B. V.保留所有权利。
In recent years, an increasing number of studies have focussed on resolving the internal structure of ocean island volcanoes. Traditionally, active source seismic experiments have been used to image the volcano edifice. Here we present results using the analysis of compressional to shear (P to S) converted seismic phases from teleseismic events, recorded by stations involved in an active source experiment "TOM-TEIDEVS" (Ibanez et al., 2008), on the island of Tenerife, Canary Islands. We supplement this data with receiver function (RF) analysis of seismograms from the Canary Islands of Lanzarote and La Palma, applying the extended-time multitaper frequency domain cross-correlation estimation method (Helffrich, 2006). We use the neighbourhood inversion approach of Sambridge (1999a,b) to model the RFs and our results indicate magmatic underplating exists beneath all three islands, ranging from 2 to 8 km, but showing no clear correlation with the age of the island. Beneath both La Palma and Tenerife, we find localized low velocity zones (LVZs), which we interpret as due to partial melt, supported by their correlation with the location of historical earthquakes (La Palma) and recent earthquakes (Tenerife). For Lanzarote, we do not sample the most recently volcanically active region and find no evidence for a LVZ. Instead, we find a simple gradational velocity structure, with discontinuities at similar to 4, 10 and 18 km depth, in line with previous studies. (C) 2012 Elsevier B.V. All rights reserved.