刊中刊

双重打击：引发汤加大海啸的因素 发生在2009年9月，席卷萨摩亚和北汤加群岛的海啸是由海沟外坡上的一次8级地震引起的，在这个地方，太平洋板块进入消减带时发生弯曲。这里最初被认为是该海啸的唯一来源，但一个更为复杂的画面却正在出现。两个小组报告了在几乎同一时间和地点发生的两次地震，它们被称为“一对触发的地震”。但不清楚的是这两次地震到底是哪个触发了哪个。不管是哪种情况，这两次地震都为在邻汤加消减带上偶尔发生的大型海啸提供了一个机制。     

Tectonic geomorphology of the Ryukyu Trench-Arc-Backarc System： geological-geophysical exploration and mapping

Based on an analysis of full-cover multi-beam bathymetric data, seismic and sub-bottom profiling data, and other geological-geophysical data sets, the geomorphologic features of the Ryukyu trench-arc-backarc (T-A-BA) system are delineated, and a geomorphologic map of the system is compiled. The results show that the evolution and spatial distribution patterns of the geomorphologic types of the Ryukyu T-A-BA system are controlled mainly by tectonic movements. The tectonic geomorphologic characteristics of the Ryukyu Arc (RA) differ distinctly from those of the East China Sea (ECS) continental shelf and slope. In term of geological structures, RA consists of the Tokara volcanic ridge, the Ryukyu folded ridge, the fore-arc accretion-wedge ridge and the Amami Depression and the fore-arc depressions between the ridges, which is composed of a complex of alternating island-slope ridges and fault basins. The slope of the ECS is a passive continental margin with stepwise faults. The Okinawa Trough (OT) is a backarc rift in which tectonicmovements are intensive, with active volcanic and hydro-thermal eruptions and sea floor spreading. The development of geomorphic features of the OT is controlled by the central en echelon spreading axes, the faults along the ECS slope and the marginal faults to the west of the Tokara volcanic ridge. The geomorphic complex of the OT is arranged in the following pattern: the en echelon grabens and volcanic chains formed by rifting and spreading lie in the central part of the trough, the turbidite plains incliningwards from the slope foot of the ECS lie in the westeru-northwesteru parts of the OT, and the volcaniclastic deposit plains inclining westward-northwestwards from the western slope foot of the RA lie in the easteru-southeasteru parts of the OT. In term of tectonic geomorphology, the OT forms a natural division between the sheff of the ECS and the RA.     

Indentation tectonics in the accretionary wedge of middle Manila Trench

Based on the multibeam morpho-tectonic analysis of the Manila Trench accretionary wedge and its indentation tectonics and the contrasting researches with other geological and geophysical data, three tectonic zones of the wedge are established, faulting features, tectonic distribution and stress mechanism for the indentation tectonics are analyzed, oblique subduction along Manila Trench with convergent stress of NW55~ is presented, and the relationship of the ceasing of Eastern Subbasin spreading of South China Sea Basin to the formation of subduction zone of Manila Trench is discussed. By the model analysis and regional research, it is found that the seamount subduction along Manila Trench does not lead to the erosion of the accretionary wedge and the oblique subduction actually is a NWWtrending obduction of Luzon micro-plate that results from the NWW-trending displacement of the Philippine Sea plate.     

“蛟龙”号和深潜器的定义

2012年6—7月间,中国自主设计制造的深潜器“蛟龙”号在太平洋的马里亚纳海沟进行深海潜水试验,潜水深度达到水下7062米。这标志着中国已跻身国际“深潜俱乐部”,这个俱乐部的成员至今只有法国、美国、俄罗斯和日本。     

“蛟龙”建奇功 海沟现真容

"我感觉到一种强烈的与世隔绝感,像是在外太空的星球表面,在另一个时空。"这是美国导演卡梅隆从马里亚纳海沟归来接受记者采访所发表的感想。最近,中国的蛟龙号深潜器在马里亚纳海沟成功突破7000米深度。神秘的马里亚纳海沟,再次成为世人瞩目的焦点。马里亚纳海沟什么样全世界深度大于6000米海域很少,只占海洋总面积的1.2%。在深     

巨石体引发“地球大变动”

大约在5000万年前发生过改变地球模样的重大事件 巨石体是海洋板块由海沟向下插入地幔的部分，在深度大约为660千米附近所形成的巨大岩石块。当巨石体迅速向更深处陷落发生坍塌时，其影响足以导致地幔的融合和改变地幔的流动速度及行进路线，从而形成海沟和火山岛链等地形。截至去年的研究表明，这种看法已经不是假说，而真的有可能是在过去曾经发生过的事件。巨石体坍塌是怎么回事，发生这种事件的机制是什么？它们对地球的环境又产生过什么影响？本文结合这些问题来介绍有关巨石体研究的最新成果。[编者按]     

取自深海的泥泞微生物

SubmarinemissionfindslifeinthedeepesttrenchonEarth.TheirhomeliesfurtherbeneathsealevelthanEverest'speakrisesaboveit.Andyettinyor鄄ganismshavebeenfoundlivingattheverybottomofthePacificOcean'sdeepesttrench,there鄄motestspotontheglobe.Themicroscopicorganisms,calledforaminifera,liveinmudatthebottomofChallengerDeepintheMarianaTrench,almost11kilometresbeneaththewavesofthewesternPacificOcean.Thepres鄄sureatthisdepthisacrushing1,090timesthatatthesurface.ResearchersledbyHiroshiKitazatooftheJapanA…