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タイトル: A Tectonic Stress Trajectory Map of Alaska Using Information from Volcanoes and Faults
その他のタイトル: 火山と断層の情報から作ったアラスカのテクトニック主応力線図
著者: Nakamura, Kazuaki
Plafker, George
Jacob, K. H.
Davies, J. N.
著者(別言語): 中村, 一明|
発行日: 1980年8月25日
出版者: 東京大学地震研究所
掲載誌情報: 東京大学地震研究所彙報. 第55冊第1号, 1980.8.25, pp. 89-100
抄録: A preliminary tectonic stress trajectory map for the Alaska region is compiled from 44 directions of maximum horizontal compression obtained from published data about post-Miocene volcanoes and late Quaternary faults. The pattern of the trajectory lines gives an averaged picture of the tectonic stress field during the late Quaternary. The pattern correlates with relative motion between the Pacific and North America plates, as judged by parallelism between the trajectory lines and direction of convergence of the two plates. Within a zone several hundred kilometers wide along the plate boundary, the mapped trajectories coincide with P-axes (i.e. direction of maximum principal stress, σ1) in a three-dimensional stress system. In the eastern Bering sea and interior Alaska, P-axes appear to be vertical and the mapped trajectories probably represent the B or axes of intermediate stress (σ2). Thus, the compressive stress in the arc area is replaced in the back-arc region by tensional stresses which are probably caused by a large-scale, deep-seated stress source. Despite this tensional stress field in the back-arc region no coherent spreading is observed there behind the Alaska Aleutian arc system. It is suggested that back-arc regions are potentially extensional but that the formation of back-arc basins depends on a mechanism other than subduction near the trench so that the space of an extending back-arc region is appropriately filled.
URI: http://hdl.handle.net/2261/12749
ISSN: 00408972


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