台湾近期中强地震频繁

最近一个月 ,我国台湾省连续发生中强地震 ,具体情况如下。1 ) 2 0 0 3年 6月 9日上午 9时 52分在台湾宜兰发生里氏 6 3级地震 ,震中位于宜兰南澳地震站东面 2 5km处 ,震源深度 2 1 3km。主震后 ,半天就发生 1 0 0多次余震 ,其中包括多次 4级以上余震 ,最大的 1次余震为 5 3级。这是今年以来台湾最大的 1次地震。2 ) 6月 1 7日凌晨 2时 33分在花莲发生里氏 5 9级地震 ,震中位于花莲红叶地震站东北 2 9 7km处 ,震源深度 1 8 8km。3) 6月 1 7日清晨 6时 38分在花莲红叶地震站东面 2 7 8km处又发生里氏 5 2级地震 ,震源深度 1 9 9km。我国台…     

2001年10月27日云南永胜6.0级地震概述

1　地震参数据中国地震台网测定 ,2 0 0 1年 1 0月 2 7日 1 3时 3 5分 (北京时间 ) ,在云南省丽江地区永胜县发生 6.0级地震。震中位于永胜县涛源乡和期纳镇交界处 ,距永胜县城约 80 km ( 2 6.2°N,1 0 0 .6°E) ,震源深度 1 0 km。截至 2 8日已发生余震 1 0 1次 ,最大震级为4.2级。2　地震破坏及伤亡情况这次地震丽江永胜县和大理白族自治州的宾川县、鹤庆县是重灾区。截至目前 ,地震造成1人死亡 ,2 2 0人受伤 ,1 589人无家可归 ,2万多人急需转移安置。地震还造成 9798户的房屋倒塌和严重损坏 ,共计 57971间 ,其中 ,民房倒塌1 3 0 4间 ,学…     

2000年10月6日日本发生7.3级强烈地震

1　地震概况2 0 0 0年 1 0月 6日当地时间下午 1点 30分 (北京时间 1 2点 30分 )位于日本本州半岛的鸟取县西部发生了 7.3级强烈地震 ,地震持续了大约 40 s。此次地震属于“内陆直下型”,震中位于北纬 35 .4度 ,东经 1 33.7度 ,震源深度为 1 0 km。日本四国、近畿等地区都有强烈震感。地震过后 ,鸟取县地区余震持续未断 ,接连发生了 2 0 0多次超过 1级的余震。 7日上午鸟取县附近地区仍有余震 ,最大震级为 4.9级。此外 ,在日本国土另一端的北海道地区也在 7日清晨发生 4.6级的地震 ,不过震中位于地下6 0 km处 ,未造成任何灾情。2　震害情况…     

2003年5月1日土耳其发生6.4级强烈地震

20 0 3年 5月 1日凌晨当地时间 0 3时 2 7分 (格林尼治时间 0 0时 2 7分 ) ,在土耳其东南部发生里氏 6 4级强烈地震 ,震中位于土耳其首都安卡拉以东 70 0km的宾格尔市的郊外。主震后 ,继发 1 0 0多次余震 ,其中至少有一次余震为 5级。地震造成严重的生命和财产损失。据报道 ,在这次地震中 ,宾格尔省共有82幢房屋倒塌 ,1 6 7人遇难 ,537人受伤。其中 ,宾格尔市郊一所名叫切尔蒂克苏尤的寄宿小学伤亡最为严重 ,全校 1 98名学生居住的学生宿舍楼在地震中被夷为平地 ,造成 84名学生和 1名教师死亡。地震还造成供电中断、通讯不畅和桥梁坍塌。…     

2002年2月3日土耳其发生 强烈地震

20 0 2年 2月 3日 ,土耳其西南部的阿菲永省发生了 2次强烈地震 ,造成了严重破坏 ,至少使 45人丧生 ,2 0 0多人受伤 ,1 0 0幢建筑物倒塌。据土耳其伊斯坦布尔地震研究中心测定 ,第一次地震发生在 2月 3日当地时间上午 9时1 1分 ,震级为里氏 6.0。第二次地震发生在 2小时之后 ,震级为 5.3。这 2次地震的震中均在阿菲永省的博尔瓦丁镇。据报道 ,这 2次地震后 ,至少发生了 7次余震。据法国斯特拉斯堡地球科学观测中心测定 ,2月 3日首先发生的是里氏 5.6级地震 ,2小时后发生的才是里氏 6.0级地震。据中国华北遥测地震台网测定 :地震发生时间为 2…     

2003年7月21日云南大姚发生6.2级地震

据中国地震局地球物理研究所测定 ,2 0 0 3年 7月 2 1日 2 3时 1 6分 (北京时间 )在我国云南地区 ( 2 5 9°N ,1 0 1 2°E)发生一次MS6 2地震及多次较强余震 ,造成了较大的人员伤亡和财产损失。1　地震震源参数据地震部门测定 ,这次地震的震中位于大理市东北约 1 0 0km处的楚雄彝族自治州大姚县昙华乡 ,距大姚县县城约 30km ,距云南省省会昆明市约 1 80km ,震源深度 6km。这次地震持续了几十秒。主震发生后 ,余震不断 ,截至 7月 2 8日 ,在大理、大姚、洱源、永胜、通海等地共发生 4 89次余震 ,其中 7月 2 4日上午 7时 52分在昙华乡发生…     

2000年1月15日云南省姚安县发生5.9、6.5级强震

据云南省地震遥测台网测定 :2 0 0 0年 1月 1 5日 0 6时 0 9分 0 1秒和 0 7时 37分 0 5秒分别在 2 5°34′Ｎ ,1 0 1°0 5′Ｅ ;2 5°35′Ｎ ,1 0 1°0 7′Ｅ ,距姚安县城西北约 1 0ｋｍ处先后发生了 5 9级和 6 5级两次强震 ,震源深度初定为 30ｋｍ。截至 2月 9日共记录到 1级以上地震共 463次 ,其中 1～ 1 9级 2 80次 ,2～ 2 9级 1 56次 ,3～ 3 9级1 6次 ,4～ 4 9级 7次 ,5 9、 6 5级各一次 ,最大余震为 4 7级 ,余震震中高度集中于 7× 8(ｋｍ2 )范围内。现场考察结果显示极震区长轴为Ｎ1 2°Ｅ的椭圆。极震区烈度为ＶＩＩＩ度 ,位于姚安…     

伊朗东南部发生里氏6.8级强烈地震

20 0 3年 1 2月 2 6日德黑兰当地时间上午 5点 2 8分 ,伊朗东南部地区发生里氏6 8级强烈地震 (根据伊朗地震台网修正后的数据。美国地震台网测定震级 6 7,中国地震台网测定震级为 7 0 ) ,震中位置为2 9 0 1°N ,58 30°E ,震源深度 33km。地震震中位于距克尔曼省省会克尔曼市约 1 80km的巴姆市。地震造成了大面积破坏 ,巴姆市有 6 0 %的房屋倒塌 ,一些具有历史价值的古迹也变成了废墟 ,巴姆及其附近地区的通讯、水、电供应均遭中断。联合国人道事务协调办公室派往伊朗巴姆地震灾区的救灾协调人员 1 2月 2 9日乘飞机对伊朗地震灾区进行了…     

2003年4月17日青海省德令哈发生6.6级地震

据中国地震台网测定 ,2 0 0 3年 4月 1 7日北京时间 0 8时 48分 ,青海省 (北纬37 5度 ,东经 96 8度 )发生 6 6级地震 ,震中距德令哈市约 50km。据中国地震局新闻办公室称 ,该震发生后 ,中国地震局局长宋瑞祥于 1 7日中午即率数位地震专家飞赴西宁 ,赶往德令哈。中国地震局派出的现场工作组一行 1 7人随后亦乘机前往地震现场。据已赶到此次地震极震区———怀头他拉乡的青海海西州地震工作人员向青海省地震局反映的情况 ,震中区域除个别土坯房和围墙倒塌外 ,目前还没有发现人员伤亡。2003年4月17日青海省德令哈发生6.6级地震@董泰…     

2002 年甘肃玉门 5.9 级地震的地质背景研究

野外调查结果表明 ,2 0 0 2年 1 2月 1 4日发生在甘肃省玉门地区的 5 9级地震 ,其宏观震中和仪器震中都位于祁连山北缘断裂上。震中区烈度为Ⅶ度 ,Ⅶ度区呈长椭圆形 ,长轴走向N6 5°W ,长度为 1 5km ,短轴走向N2 5°E ,长度为 9km。发震断层应为祁连山北缘断裂的次级断裂旱峡—大黄沟断裂 ,本次地震的余震都分布于该断裂附近。     

强震观测网、高灵敏度地震观测网、地中强震观测网、宽频带地震观测网

阪神·淡路大震灾后 ,日本着手对原有的地震观测体制作彻底改革 ,多项全国性配置地震计的计划同时开始启动。地震引起的地面晃动的程度不尽相同 ,无感微小地震引发的晃动仅有 0 .0 0 1 μm,频率为1 0 Hz;巨大地震引起的地面晃动的幅度高达 2～ 3 m,周期也有几十秒。虽说都称之为地震计 ,但由于地震动的振幅和频率涉及的范围太大 ,所以应针对观测对象选用不同类型的地震计。下面介绍不同类型的观测网。1　强震观测网 ( K- NET)无论大地有多大的晃动都能将其准确记录下来的地震计称之为强震计。它构造坚实 ,信号明确 ,通常设置在地表 ,对了…     

Age, geology, geophysics, and geochemistry of Mahukona Volcano, Hawai`i

The size, shape, and magmatic history of the most recently discovered shield volcano in the Hawaiian Islands, Mahukona, have been controversial. Mahukona corresponds to what was thought to be a gap in the paired sequence (Loa and Kea trends) of younger Hawaiian volcanoes (<4?Ma). Here, we present the results of marine expeditions to Mahukona where new bathymetry, sidescan sonar, gravity data, and lava samples were collected to address these controversies. Modeling of bathymetric and gravity data indicate that Mahukona is one of the smallest Hawaiian volcanoes (～6,000?km³) and that its magmatic system was not focused in a long-lived central reservoir like most other Hawaiian volcanoes. This lack of a long-lived magmatic reservoir is reflected by the absence of a central residual gravity high and the random distribution of cones on Mahukona Volcano. Our reconstructed subsidence history for Mahukona suggests it grew to at least ～270?m below sea level but probably did not form an island. New ⁴⁰Ar–³⁹Ar plateau ages range from 350 to 654?ka providing temporal constraints for Mahukona’s post-shield and shield stages of volcanism, which ended prematurely. Mahukona post-shield lavas have high ³He/⁴He ratios (16–21?Ra), which have not been observed in post-shield lavas from other Hawaiian volcanoes. Lava compositions range widely at Mahukona, including Pb isotopic values that straddle the boundary between Kea and Loa sequences of volcanoes. The compositional diversity of Mahukona lavas may be related to its relatively small size (less extensive melting) and the absence of a central magma reservoir where magmas would have been homogenized.     

The Yecheng,Xinjiang, China,earthquake of February 14, 1980

In this study, we have checked the location and focal depth of the Yecheng earthquake (m _b = 6.0, maximum intensity VII) of February 14, 1980. The result shows that this is an intermediate event with a focal depth of 90 km. The microepicenter is located at 36. 4°N, 76, 9°E, while the macroepicenter is at 37.3°N, 76.9°E, 90 km to the north of the microepicenter. This is the first destructive intermediate event in China which led to a damage as severe as of intensity VII. The focal mechanism of the event is determined to be of thrust type. Combined with the analysis of seismological and geological data in surrounding area, the possible relation between the event and plate movement has been discussed. The result in this paper indicates that in some particular place, the destructive effect of intermediate event should be considered in seismic hazard assessment.     

Sun, climate, hunger, and mass migration

Paleoclimatic studies indicate four epochs of global cooling during the last 4 000 years, i. e. during the few centuries before and after 2000 BC, 800 BC, 400 AD, and 1 600 AD; the quasiperiodicity corresponds to cyclic variation of solar activity. Global temperature changes influenced regional precipitation patterns: Northern Europe was wetter while the middle- and low-latitude lands were more arid during colder epochs. Both sets of cold climatical conditions were unfavorable for agricultural production. Historical records show that large demographic movements in history took place because of crop failures and mass starvation, rather than escaping from war zones. The “wandering” of the Germanic tribes during the first two or three centuries of the Christian Era is one example. Whereas the accelerated release of carbon dioxide from the burning of fossil fuels is ultimately to cause global warming, historical evidence indicates, however, that global warming has been on the whole a blessing to mankind. Global cooling, on the other hand, has curtailed agricultural production and has led to famines and mass migrations of people. Perhaps the most important task at the present is not so much computer-modelling of greenhouse effect on global climate, but water-management and agricultural researches to insure food-supply for an everincreasing world population.     

Physical properties,vitrinite reflectance,and microstructure of coal,Taiyuan Formation,Qinshui Basin,China

In this study, we experimentally established the relationship between physical properties, vitrinite reflectance, and microstructure of coal, Taiyuan Formation, Qinshui Basin, China using representative coal samples collected from three different mines via the rock mechanics testing system (MTS). We analyzed the organic macerals, vitrinite reflectance, and microstructure of 11 coal samples using petrography and scanning electron microscopy (SEM). The experimental results suggest that (1) the elastic parameters can be described by linear equations, (2) both P-and S-wave velocities display anisotropy, (3) the anisotropy negatively correlates with vitrinite reflectance, and (4) the acoustic velocities and Young’s modulus are negatively correlated with the volume of micropores. The derived empirical equations can be used in the forward modeling and seismic inversion of physical properties of coal for improving the coal-bed methane (CBM) reservoir characterization.     

Spatial distribution,source apportionment,and associated risks of trace metals (As,Pb, Cr,Cd, and Hg) from a subtropical river,Gomti, Bangladesh

Sediment samples from the Gomti River basin were investigated to determine and evaluate trace metal concentrations,their biological effect,and potential ecological and human health risks for adults and children.The mean concentrations of trace metals were organized in the descending order of mercury(Hg)(0.08 mg/kg)>chromium(Cr)(0.06 mg/kg)>lead(Pb)(0.05 mg/kg)>arsenic(As)(0.02 mg/kg)>cadmium(Cd)(0.01 mg/kg).The current study illustrated that metals were attributed to the area from natural sources and different anthropogenic sources especially from industries.However,the concentration levels were lower than the sediment quality guidelines(SQGs)based on the effect-range classifications of threshold effect concentration(TEC)and probable effect concentration(PEC).Therefore,the concentration of the elements showed no adverse biological effects on aquatic organisms.The evaluated potential ecological risk index also revealed the low toxicity to the aquatic environment.Moreover,the applied sediment quality indices,geo-accumulation index(Igeo),contamination factor(CF),and contamination severity index(CSI)suggested that the contamination levels of the elements were in the acceptable range,and the contamination had not notably impacted on the sediment quality.The risk index(HI)concerning age groups was significantly less than the threshold limit of 1 indicating that the contamination had no non-carcinogenic risk effect.The total carcinogenic risk(TCR)was less than a risk value of 1×10⁴.Hence,the current study suggests that immediate remediation is not required due to an absence of alarming conditions in the study area.Proper monitoring of the attribution of the metal elements should be done for the betterment of human and environmental health。