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171.
172.
海南岛及其邻区地震活动特征分析 总被引:2,自引:0,他引:2
将海南岛及其邻近地区划分为3地震活动区和4个地震活动条带,系统地研究了各区、带地震活动的时间序列特征及空间分布特点,为海南地震时、空、强三要素预报提供参考依据。 相似文献
173.
南岭成矿带是太平洋及印度洋板块对中国大陆板块联合作用的结果。囊括大量稀有-有色金属矿床的中心弧形构造-岩浆岩系正是这个“钳式”应力场作用的集中体现,“深部叠加-重熔”——以板块持续运动和相对高速率运动产生并贮集能量为前提,以俯冲板块不断带入新的挥发物质为条件,随着动力热和挥发组分的不断回流—汇集—贮集而使仰冲板块深部预热的原地或途中固化-半固化的先期熔融的岩浆岩发生了二次甚至多次的熔融作用。 相似文献
174.
Kevin Hall 《地球表面变化过程与地形》1986,11(2):131-142
Rock moisture content is a major control of mechanical weathering, particularly freeze-thaw, and yet almost no data exist from field situations. This study presents moisture content values for rocks, taken from a variety of positions and conditions, in the maritime Antarctic. Additional information regarding the amount of water the rock could take up, as observed from laboratory experiments, is also presented. The results show that the approaches used in simulation experiments, particularly that of soaking a rock for 24 hours, may produce exaggerated results. It was found that the saturation coefficient (S-value) was a good indicator of frost susceptibility (based on water content) but that the derivation of that value may underestimate the potential of some rocks. The distribution of moisture within rocks is seen as an important, but unkown, factor. The results of these field moisture contents suggest that for simulations of freeze-thaw or hydration to be meaningful then they should have rock water contents based on field observations. 相似文献
175.
Field survey of the 1994 Mindoro Island,Philippines tsunami 总被引:2,自引:0,他引:2
Fumihiko Imamura Costas E. Synolakis Edison Gica Vasily Titov Eddie Listanco Ho Jun Lee 《Pure and Applied Geophysics》1995,144(3-4):875-890
This is a report of the field survey of the November 15, 1994 Mindoro Island, Philippines, tsunami generated by an earthquake (M=7.0) with a strike-slip motion. We will report runup heights from 54 locations on Luzon, Mindoro and other smaller islands in the Cape Verde passage between Mindoro and Luzon. Most of the damage was concentrated along the northern coast of Mindoro. Runup height distribution ranged 3–4 m at the most severely damaged areas and 2–4 in neighboring areas. The tsunami-affected area was limited to within 10 km of the epicenter. The largest recorded runup value of 7.3 m was measured on the southwestern coast of Baco Island while a runup of 6.1 m was detected on its northern coastline. The earthquake and tsunami killed 62 people, injured 248 and destroyed 800 houses. As observed in other recent tsunami disasters, most of the casualties were children. Nearly all eyewitnesses interviewed described the first wave as a leading-depression wave. Eyewitnesses reported that the main direction of tsunami propagation was SW in Subaang Bay, SE in Wawa and Calapan, NE on Baco Island and N on Verde Island, suggesting that the tsunami source area was in the southern Pass of Verde Island and that the wave propagated rapidly in all directions. The fault plane extended offshore to the N of Mindoro Island, with its rupture originating S of Verde Island and propagating almost directly south to the inland of Mindoro, thereby accounting for the relatively limited damage area observed on the N of Mindoro. 相似文献
176.
本文以卫星图象信息为依据,结合野外调研,提出并确定了华北块体北缘存在:块体缝合线,褶皱-逆掩断层带,后孤碰撞带(断裂带),台槽过渡带,岩浆弧,以及燕山-喜山期的NNE向岩浆活动带、断陷带(断陷盆地)等双重构造的新认识。并在此基础上,对华北块体北缘与深成岩浆岩,燕山期岩浆活动带(包括火山岩带)有关的铀矿化作用的独特构造环境及“岩浆”型,断陷带中和面型等主要铀矿床成矿模式和铀成矿带的划分及其划分依据作了研究和探讨。并以铀矿床的实例作为佐证。 相似文献
177.
内蒙古中西部多岛海构造演化 总被引:10,自引:0,他引:10
内蒙古中西部大陆由一个微大陆、三条弧后盆地和三条火山岛弧,即华北微大陆、白云鄂 傅弧后盆地、白乃庙火山岛弧、温都尔庙弧后盆地、苏尼特左-锡林浩特火山岛弧、贺根山弧后盆 地和二连浩特-锡林郭勒火山岛弧组成。经过了长期而复杂的微大陆和火山弧的裂解、弧后盆地 的消减衰亡及弧-陆和弧-弧碰拉等构造演化,才最终形成今天所见到的这种构造样式。 相似文献
178.
179.
KENNETH R. OLWIG 《Geographical review》2007,97(2):175-190
ABSTRACT. I use my personal experience as an islander doing fieldwork among islanders in the West Indies to explore the meaning of “insularity.” I then expand on that personal experience by drawing on literary sources, particularly Homer's the Odyssey and Herman Melville's Moby Dick, both of which express an island worldview. The island worldview is contrasted and compared with the continental worldview on the basis of differing modes of navigation and cartography and differing modes of orientation as defined by cognitive psychologists. 相似文献
180.
Pantelis Soupios Nikos Papadopoulos Ilias Papadopoulos Maria Kouli Filippos Vallianatos Apostolos Sarris Thrassyvoulos Manios 《Environmental Geology》2007,53(3):661-675
An integrated suite of environmental methods was used to characterize the hydrogeological, geological and tectonic regime
of the largest waste disposal landfill of Crete Island, the Fodele municipal solid waste site (MSW), to determine the geometry
of the landfill (depth and spatial extent of electrically conductive anomalies), to define the anisotropy caused by bedrock
fabric fractures and to locate potential zones of electrically conductive contamination. A combination of geophysical methods
and chemical analysis was implemented for the characterization and management of the landfill. Five different types of geophysical
surveys were performed: (1) 2D electrical resistance tomography (ERT), (2) electromagnetic measurements using very low frequencies
(VLF), (3) electromagnetic conductivity (EM31), (4) seismic refraction measurements (SR), and (5) ambient noise measurements
(HVSR). The above geophysical methods were used with the aim of studying the subsurface properties of the landfill and to
define the exact geometrical characteristics of the site under investigation. 相似文献