ORIENTATION AND GROWTH OF HAWAIIAN VOLCANIC RIFTS - EFFECT OF REGIONAL STRUCTURE AND GRAVITATIONAL STRESSES
ORIENTATION AND GROWTH OF HAWAIIAN VOLCANIC RIFTS - EFFECT OF REGIONAL STRUCTURE AND GRAVITATIONAL STRESSES
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DOI：
10.1098/rspa.1972.0115
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发表时间：
1972-01-01
影响因子：
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通讯作者：
JACKSON, ED
中科院分区：
文献类型：
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作者：
FISKE, RS;JACKSON, ED
从可爱岛延伸到夏威夷的 14 座玄武岩盾状火山的裂谷由数千条堤坝组成，这些堤坝由中央火山管道的周期性渗漏横向供给。据信，各个堤坝都是薄而陡峭的叶片，从上到下长达数公里，水平向外延伸长达 120 公里。堤坝大部分包含在火山建筑物内，并且由于位置较浅，堤坝传播的方向被解释为受到这些建筑物内的重力应力的强烈影响。简单的孤立地盾，如可爱岛和西莫洛凯岛，具有几乎对称的应力场，仅受区域应力的轻微影响，注入这些火山的岩堤很少或没有聚集成明确的裂谷的趋势。其他火山，如库劳火山和基拉韦厄火山，刺穿了先前存在的邻近火山的厚厚的倾斜的围裙。从这些中心延伸出来的堤坝受到它们生长所在的倾斜围裙的重力应力场的强烈影响。因此，它们聚集成轮廓分明的裂痕，其方向大致垂直于这些停机坪的下坡方向。除了少数例外，夏威夷火山链东南部的 14 座火山中，有 8 座符合这种增长模式；太平洋区域结构对裂谷方向的影响仅在 6 座火山中被怀疑，这些火山生长为简单、孤立的盾状，远离任何邻近火山的重力应力的影响。
The rifts of the 14 basaltic shield volcanoes that extend from Kauai to Hawaii are composed of thousands of dykes that were fed laterally by periodic leakages from central volcanic conduits. Individual dykes are believed to be thin, steeply dipping blades, several kilometres from top to bottom, that extend horizontally outward for as much as 120 km. The dykes are contained largely within the volcanic edifices, and, because of such shallow emplacement, the direction of dyke propagation is interpreted to be strongly influenced by the gravitational stresses within these edifices. Simple isolated shields, such as Kauai and West Molokai, had nearly symmetrical stress fields, influenced only slightly by regional stresses, and the dykes injected into these volcanoes had little or no tendency to cluster into well-defined rifts. Other volcanoes, such as Koolau and Kilauea, pierced the thick, sloping apron of pre-existing neighbour volcanoes. The dykes that propagated from these centres were strongly influenced by the gravitational stress fields of the sloping aprons in which they grew. Accordingly, they clustered into well-defined rifts oriented roughly perpendicular to the downslope direction of these aprons. With only minor exceptions, 8 of the 14 volcanoes forming the southeast part of the Hawaiian chain conformed to this pattern of growth; the influence of regional Pacific structure on rift orientation is suspected in only 6 volcanoes that grew as simple, isolated shields, away from the influence of gravitational stresses of any neighbour volcano.