Deep-sea magnetic survey using autonomous underwater vehicle r2D4 on Bayonnaise knoll caldera
Deep-sea magnetic survey using autonomous underwater vehicle r2D4 on Bayonnaise knoll caldera
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使用自主水下航行器 r2D4 在巴约讷山丘火山口进行深海磁力勘测
DOI：
10.3124/segj.63.427
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Yoshitaka Hosoi
中科院分区：
文献类型：
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作者：
C. Honsho;T. Ura;K. Tamaki;K. Nagahashi;H. Shibazaki;Yoshitaka Hosoi
2008年3月和10月，利用东京大学工业科学研究所开发的自主水下航行器（AUV） r2D4对位于伊豆-小笠原岛弧裂谷带东部边缘的Bayonnaise丘火山口的北部和东南部进行了深海调查。利用两次潜水调查收集的磁场矢量数据进行磁场反演，揭示海底磁化分布。反演结果成像了两个高磁化区域，分别位于火山口底北缘和火山口壁东南部。在火山口中发现的磁化高点似乎位于一条玄武岩小丘链的推断线上，这条玄武岩小丘链延伸到贝onnaise小丘的南北，这表明它们可能是由小丘链的火山活动产生的侵入性玄武岩，而不是由贝onnaise小丘的厚地壳阻挡的喷发。其中一个高磁化区位于白井矿床附近，表明玄武岩岩浆侵入可能诱发了白井遗址的热液活动。研究发现，一些热液位置与地壳磁化强度较低有关，认为这是由于热液循环导致磁性矿物蚀变和地壳岩石磁化强度降低所致。然而，白井位置显然与明显的低磁化无关。这可能是因为贝onnaise小丘几乎由英安岩熔岩和碎片组成，它们具有弱磁化，蚀变和退磁的玄武岩与附近的英安岩难以区分。高磁化可能仅代表侵入体中相对较远的未变质部分，而白井部位可能被变质和退磁部分所覆盖。本研究中获得的磁化分布的横向分辨率受限于分析过程中应用的高截止滤波器，而不受数据本身分辨率的限制。海洋磁测的重点已从海面向深海转移，提高分析方法，充分利用高分辨率数据已势在必行。
In March and October in 2008 deep-sea surveys by using the autonomous underwater vehicle (AUV) r2D4 developed by Institute of Industrial Science, The University of Tokyo, were conducted on the northern and southeastern parts of the Bayonnaise knoll caldera, located on the eastern margin of the rift zone of the Izu-Ogasawara island arc. The magnetic vector field data collected during the two dive surveys were used for magnetic inversion to reveal the magnetization distribution on the seafloor. The inversion result imaged two areas of high magnetization in the northern margin of the caldera floor and in the southeastern caldera wall. The magnetization highs found in the caldera seem to lie on an inferred line of a basaltic knoll chain running to the north and south of the Bayonnaise knoll, suggesting that they may represent intrusive basaltic rocks produced by the volcanic activity of the knoll chain, that could not come up to eruption blocked by the thick crust of the Bayonnaise knoll. One of the high magnetization areas is located adjacent to the Hakurei deposit, indicating that the basaltic magma intrusion may have induced the hydrothermal activity of the Hakurei site. It has been found that some hydrothermal sites are associated with low crustal magnetization, which is considered resulting from the alteration of magnetic minerals and reduction in magnetization of crustal rocks due to the hydrothermal circulation. However, the Hakurei site is apparently not associated with obvious low magnetization. That is probably because the Bayonnaise knoll almost consists of dacite lava and fragments which have weak magnetization and altered and demagnetized basaltic rocks would be indistinguishable from nearby dacite rocks. The high magnetization may represent only the unaltered part of the intrusive body that is relatively far from the hydrothermal site and the Hakurei site may be underlain by the altered and demagnetized part. The lateral resolution of the magnetization distribution obtained in this study is limited by the high-cut filter applied in the analysis process, not by the resolution of data itself. The focus of marine magnetic survey has been shifting from sea-surface to deep-sea and it is imperative to progress the analysis method to make the most of high resolution data.
H.264编码器DCT的硬件实现及其评估
DOI：
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发表时间：
2009
期刊：
影响因子：
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作者：
Choong Geun Lee;V. G. Moshnyaga and K. Hashimoto;宮田康治
通讯作者：
宮田康治
无人潜航器“r2D4”前往印度中部洋中脊系统裂谷
DOI：
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发表时间：
2007
期刊：
影响因子：
--
作者：
Ura;T.;K. Tamaki;A. Asada;K. Okamoto;K. Nagahashi;T. Sakamaki;T. Gamo;K. Okino;T. Obara;K. Nakane;T. Obata;Y. Ooyabu;N. Yamaoka;Y. Orihashi;J. Han;H. Koyama;H. Sugimatsu
通讯作者：
H. Sugimatsu