中华民族不会忘记——有一种力量叫科学

“科学,教会人们过负责任的生活”,这句话出自美国的“2061计划”。 科学,是一种价值观、是探索自然规律的过程;科学还是“一只高高飞翔的鸟”,具有太多的动态性、发展性成分。有国内外专家认为：今天的科学是一种职业活动,是一种社会建制,是一种社会工具,是一个知识体系。是一套研究方法。但是“5．12”地震至今,科学是自救、抢救、拯救和挽救,是生命的福音;科学是巨大的智慧和力量。是重建家园、创造美好生活的强音。     

突变理论在地震成因及地震危险性与岩体稳定性评价研究中的应用

地震是一种非连续的突变现象,孕震系统是一个很繁杂的系统。这个系统是非线性的,甚至是高度非线性的。系统的过程可用非线性微分方程描述,非线性系统不同干线性系统的特点,其一是两个解的线性迭加一般不再是方程的解;其二是非线性体系可能有多个定态解(或周期解),其中有些是稳定的,有些是不稳定的。随着参数的变化,这些定态的稳定性会发生变化,出现分歧或临界现象。突变论是研究这种临界行为的有力工具,因为突变论通过剖分引理证明了系统结构的不稳定性并不取决于可能达成千上万的状态变量的总数 n,而     

遇到沙尘暴 你该怎么办?

正春天是多风的季节,也是沙尘暴的季节。沙尘暴是沙暴和尘暴的总称。指强风将地面大量沙尘卷入空中使空气特别浑浊,水平能见度低于一千米的天气现象。产生沙尘暴的条件主要有两方面:一是要有强风,二是地面要有大量的沙尘。中国是一个沙尘暴多发的国家。每年春季,长江以北地区都会遭受沙尘暴的袭击。北方沙尘暴多发生春季,主要是春季北方地理环境符合沙尘暴发生的条件。首先,我国北方地区靠近冬季风的策源地,冬春     

纽约世贸中心大楼遭飞机撞击和大楼坍塌产生的地震波

地震学家有时是在悲剧的背景下进行数据采集和分析工作的。这通常所指的是远离家乡在经受天然、有时是坡坏性地震影响的地区的野外工作。但目前的情况是,我们是在我们自己的城市,即纽约帕利塞兹哥伦比亚大学拉蒙特-多赫蒂地球观测站,面对的是反人民、反我们社会结构的野蛮活动。     

钻孔应变在新疆地震预报中的应用实践

简要总结了新疆十几年来,利用钻孔应变资料进行地震预报的实践。指出用钻孔应变资料预报地震是可能的,尤其是短临预报更是行之有效。实践证明打破年变规律是大震应变异常的主要特征。指数曲线是临震异常的具有规律性的可靠依据。压一张一发震的力学过程是应变异常的动态特点。     

远古花香——辽宁古生物博物馆

年轻是什么？是奋发进取的力量,是一往无前的果敢,是与时代争先的勇气,古老是什么？是千万年积淀的厚重,是印在岁月年轮里的印记,是时间雕刻的传奇。当年轻带着他的朝气与活力同古老的沉稳与厚重完美地邂逅,又会带给人们怎样的惊喜呢？ 辽宁古生物博物馆对这个问题做出了很好的解答。年轻的博物馆同数十亿年前的珍贵展品在这里完美地结合。就这样,年轻与古老携手为参观者们奉献了一场充满神奇的科普盛宴。     

利用最大熵原理估算山西地震带中强震的重现期和未来100年内中强震的发震概率

本文利用最大熵原理估算了山西地震带中强震的重现期和未来100年内中强震的发震概率。经计算,五级地震的重现期是16.2年,发震概率是0.998;六级地震的重现期是64.9年,发震概率是0.777;七级地震的重现期是260.4年,发震概率是0.330;大于等于八级地震的重现期是1570.3年,发震概率是0.062。     

在香山地震预报发展战略研讨会上的发言

这次在香山召开的地震预报发展战略研讨会可以说是一次地震预报攻关的战略研讨会。香山会议应该是一个科学会堂,将对今后产生重大作用,可以载入史册。这一次地震预报战略攻关研讨,从会议的论文集可以看出,大家准备得很认真。今天下午听了院士、专家的发言,也是高水平的。地震预报是一个尚未攻克的世界性科学难题,同时也是政府、社会的迫切需要。地震预报这个问题有人说不好搞,有人说好搞;有人说是不成功,有人说是成功。我想我们还是要用事实说话。     

关于就矿找矿论的几个问题

就矿找矿是指依据已知找矿线索而开展的一种找矿。就矿找矿是矿产勘查工作的一条指导方针,也是矿产勘查工作中的一种重要找矿方法。就矿找矿与新区找矿是找矿哲学理论体系中的一对范畴,讲的是矿产勘查工作在空间上的布局问题。     

以“河长制”促进“河长治”

<正>水是生态系统的控制要素,河湖是生态空间的重要组成,水利是生态文明建设的核心内容。全面推行河长制,是推进生态文明建设的必然要求,是解决我国复杂水问题的有效举措,是维护河湖健康生命的治本之策,是保障国家水安全的制度创新,是中央作出的重大改革举措。目前20多个省份明确今年年底前全面建立河长制。总体看,全面推行河长制起步顺利、     

Field survey report on tsunami disasters caused by the 1993 Southwest Hokkaido earthquake

Detailed field work at Okushiri Island and along the southwest coast of Hokkaido has revealed quantitatively (1) the advancing direction of tsunami on land, (2) the true tsunami height (i.e., height of tsunami, excluding its splashes, as measured from the ground) and (3) the flow velocity of tsunami on land, in heavily damaged areas. When a Japanese wooden house is swept away by tsunami, bolts that tie the house to its concrete foundation resist until the last moment and become bent towards the direction of the house being carried away. The orientations of more than 850 of those bent bolts and iron pipes (all that can be measured, mostly at Okushiri Island) and fell-down direction of about 400 trees clearly display how tsunami behaved on land and caused serious damage at various places. The true tsunami height was estimated by using several indicators, such as broken tree twigs and a window pane. The flow velocity of tsunami on land was determined by estimating the hydrodynamic force exerted on a bent handrail and a bent-down guardrail by the tsunami throughin situ strength tests.Contrary to the wide-spread recognition after the tsunami hazard, our results clearly indicate that only a few residential areas (i.e., Monai, eastern Hamatsumae, and a small portion at northern Aonae, all on Okushiri Island) were hit by a huge tsunami, with true heights reaching 10 m. Southern Aonae was completely swept away by tsunami that came directly from the focal region immediately to the west. The true tsunami height over the western sea wall of southern Aonae was estimated as 3 to 4 m. Northern Aonae also suffered severe damage due to tsunami that invaded from the corner zone of the sand dune (8 m high) and tide embankment at the northern end of the Aonae Harbor. This corner apparently acted as a tsunami amplifier, and tide embankment or breakwater can be quite dangerous when tsunami advances towards the corner it makes with the coast. The nearly complete devastation of Inaho at the northern end of Okushiri Island underscored the danger of tsunami whose propagation direction is parallel to the coast, since such tsunami waves tend to be amplified and tide embankment or breakwater is constructed low towards the coast at many harbors or fishing ports. Tsunami waves mostly of 2 to 4 m in true height swept away Hamatsumae on the southeast site of Okushiri Island where there were no coastal structures. Coastal structures were effective in reducing tsunami hazard at many sites. The maximum flow velocity at northern Aonae was estimated as 10 to 18 m/s (Tsutsumi et al., 1994), and such a high on-land velocity of tsunami near shore is probably due to the rapid shallowing of the deep sea near the epicentral region towards Okushiri Island. If the advancing direction, true height, and flow velocity of tsunami can be predicted by future analyses of tsunami generation and progagation, the analyses will be a powerful tool for future assessment of tsunami disasters, including the identification of blind spots in the tsunami hazard reduction.     

港湾中海啸流的模拟及其时空演变特征对输入条件不确定性的响应分析

一直以来,海啸波特征作为表征海啸潜在破坏性的参数指标得到了广泛应用,特别是针对近场极端海啸事件造成的灾害来说,这种表征具有较好的适用性.然而总结分析历史海啸事件造成的损失发现：在远场近岸及港湾系统中,海啸诱导的强流却是造成损失的主要原因.陆架或港湾振荡导致海啸波幅快速升降诱发强流,可能促使港工设施受到威胁及损害,进而对海啸预警服务及海事应急管理提出了新的挑战.因此,全面理解与评估海啸在港湾中诱发的灾害特征,探索港湾中海啸流的数值模拟方法,发展针对港湾尺度的海啸预警服务指导产品尤为迫切.受限于海啸流验证数据的缺乏及准确模拟海啸流技术方法的诸多不确定性,大部分海啸数值模拟研究工作主要是针对水位特征的研究及验证,可能导致对港湾中海啸灾害危险性认识的曲解与低估.本研究基于非线性浅水方程,针对夏威夷群岛三个典型港湾建立了精细化海啸数值模型（空间分辨率达到10 m）,并联合有限断层破裂模型计算分析了日本东北地震海啸在三个港湾及其邻近区域的海啸特征,波、流计算结果与实测结果吻合较好,精细化的海啸港湾模型模拟结果可信.模拟发现港湾中较小的波幅,同样可以产生强流.综合分析日本东北地震海啸波、流特征对输入条件不确定性的响应结果发现：港湾中海啸波-流能量的空间分布特征差异较大,这与港湾系统中海啸波的驻波特性相关;相比海啸波幅空间特征,海啸流特征具有更强的空间敏感性;海啸流时空分布特征对输入条件的不确定性响应比海啸波幅对这些不确定性的响应更强,海啸流的模拟与预报更有挑战性;不确定性对海啸流计算精度的影响会进一步传导放大港湾海啸流危险性的评估及对港工设施产生的应力作用的误差,合理的输入条件对海啸流的精确模拟至关重要.最后,希望通过本文的研究可以从海啸波-流特征角度更加全面认识近岸海啸灾害特征,拓展海啸预警服务的广度与深度,从而为灾害应急管理部门提供更加科学合理的辅助决策产品.     

Logic-tree Approach for Probabilistic Tsunami Hazard Analysis and its Applications to the Japanese Coasts

For Probabilistic Tsunami Hazard Analysis (PTHA), we propose a logic-tree approach to construct tsunami hazard curves (relationship between tsunami height and probability of exceedance) and present some examples for Japan for the purpose of quantitative assessments of tsunami risk for important coastal facilities. A hazard curve is obtained by integration over the aleatory uncertainties, and numerous hazard curves are obtained for different branches of logic-tree representing epistemic uncertainty. A PTHA consists of a tsunami source model and coastal tsunami height estimation. We developed the logic-tree models for local tsunami sources around Japan and for distant tsunami sources along the South American subduction zones. Logic-trees were made for tsunami source zones, size and frequency of tsunamigenic earthquakes, fault models, and standard error of estimated tsunami heights. Numerical simulation rather than empirical relation was used for estimating the median tsunami heights. Weights of discrete branches that represent alternative hypotheses and interpretations were determined by the questionnaire survey for tsunami and earthquake experts, whereas those representing the error of estimated value were determined on the basis of historical data. Examples of tsunami hazard curves were illustrated for the coastal sites, and uncertainty in the tsunami hazard was displayed by 5-, 16-, 50-, 84- and 95-percentile and mean hazard curves.     

海底地震有限断层破裂模型对近场海啸数值预报的影响

快速准确的海啸源模型是近场海啸精确预警的关键.尽管目前还没有办法直接对其进行正演定量计算,但是可以通过多源地震、海啸观测数据进行反演或联合反演推算.不同的海啸源可能导致不同的预警结论,了解不同类型海啸源适用性、评估海啸源特征差异对近场海啸的影响,无论对于海啸预警还是海啸模拟研究尤为重要.本文评估分析了6种不同同震断层模型对2011年3月11日日本东北地震海啸近场数值预报的影响,重点对比分析了有限断层模型与均一滑动场模型对近场海啸产生、传播、淹没特征的影响及各自的误差.研究表明:近场海啸波能量分布主要取决于海啸源分布特征,特别是走向角的差异对海啸能量分布影响较大;有限断层模型对海啸灾害最为严重的39°N以南沿岸地区的最大海啸爬坡高度明显优于均一滑动场模型结果;综合对比DART浮标、GPS浮标及近岸潮位站共32个站次的海啸波幅序列结果发现有限断层模型整体平均绝对/相对误差比均一滑动场模型平均误差要低,其中Fujii海啸源的平均绝对/相对误差最小,分别是0.56m和26.71%.UCSB海啸源的平均绝对/相对误差次之.3个均一滑动场模型中USGSCMT海啸源模拟精度最高.相对于深海、浅海观测站,有限断层模型比均一滑动场模型对近岸观测站计算精度更高.海啸源误差具有显著的方向性,可能与反演所采用的波形数据的代表性有关;谱分析结果表明Fujii海啸源对在12至60min主频波谱的模拟要优于UCSB海啸源.海啸源中很难真实反映海底地震破裂过程,然而通过联合反演海啸波形数据推算海啸源的方法可以快速确定海啸源,并且最大限度的降低地震破裂过程与海啸产生的不确定性带来的误差.     

Onshore tsunami deposits caused by the 1993 Southwest Hokkaido and 1983 Japan Sea earthquakes

Onshore tsunami deposits resulting from the 1993 Southwest Hokkaido and 1983 Japan Sea earthquakes were described to evaluate the feasibility of tsunami deposits for inferring paleoseismic events along submarine faults. Tsunami deposits were divided into three types, based on their composition and aerial distribution: (A) deposits consisting only of floating materials, (B) locally distributed siliclastic deposits, and (C) widespread siliclastic deposits. The most widely distributed tsunami deposits consist of the first two types. Type C deposits are mostly limited to areas where the higher tsunami runup was observed. The scale of tsunami represented by vertical tsunami runup is an important factor controlling the volume of tsunami deposits. The thickest deposits, about 10 cm, occur behind coastal dunes. To produce thick siliclastic tsunami deposits, a suitable source area, such as sand bar or dune, must be available in addition to sufficient vertical tsunami runup. Estimation of the amounts of erosion and deposition indicates that tsunami deposits were derived from both onshore and shoreface regions. The composition and grain size of the tsunami deposits strongly reflect the nature of the sedimentary materials of their source area. Sedimentary structures of the tsunami deposits suggest both low and high flow régimes. Consequently, it seems very difficult to identify tsunami deposits based only on grain size distribution or sedimentary structure of a single site in ancient successions.     

Tsunami Source of the 2010 Mentawai, Indonesia Earthquake Inferred from Tsunami Field Survey and Waveform Modeling

The 2010 Mentawai earthquake (magnitude 7.7) generated a destructive tsunami that caused more than 500 casualties in the Mentawai Islands, west of Sumatra, Indonesia. Seismological analyses indicate that this earthquake was an unusual “tsunami earthquake,” which produces much larger tsunamis than expected from the seismic magnitude. We carried out a field survey to measure tsunami heights and inundation distances, an inversion of tsunami waveforms to estimate the slip distribution on the fault, and inundation modeling to compare the measured and simulated tsunami heights. The measured tsunami heights at eight locations on the west coasts of North and South Pagai Island ranged from 2.5 to 9.3 m, but were mostly in the 4–7 m range. At three villages, the tsunami inundation extended more than 300 m. Interviews of local residents indicated that the earthquake ground shaking was less intense than during previous large earthquakes and did not cause any damage. Inversion of tsunami waveforms recorded at nine coastal tide gauges, a nearby GPS buoy, and a DART station indicated a large slip (maximum 6.1 m) on a shallower part of the fault near the trench axis, a distribution similar to other tsunami earthquakes. The total seismic moment estimated from tsunami waveform inversion was 1.0 × 10²¹ Nm, which corresponded to M_w 7.9. Computed coastal tsunami heights from this tsunami source model using linear equations are similar to the measured tsunami heights. The inundation heights computed by using detailed bathymetry and topography data and nonlinear equations including inundation were smaller than the measured ones. This may have been partly due to the limited resolution and accuracy of publically available bathymetry and topography data. One-dimensional run-up computations using our surveyed topography profiles showed that the computed heights were roughly similar to the measured ones.     

Bayesian tsunami fragility modeling considering input data uncertainty

Empirical tsunami fragility curves are developed based on a Bayesian framework by accounting for uncertainty of input tsunami hazard data in a systematic and comprehensive manner. Three fragility modeling approaches, i.e. lognormal method, binomial logistic method, and multinomial logistic method, are considered, and are applied to extensive tsunami damage data for the 2011 Tohoku earthquake. A unique aspect of this study is that uncertainty of tsunami inundation data (i.e. input hazard data in fragility modeling) is quantified by comparing two tsunami inundation/run-up datasets (one by the Ministry of Land, Infrastructure, and Transportation of the Japanese Government and the other by the Tohoku Tsunami Joint Survey group) and is then propagated through Bayesian statistical methods to assess the effects on the tsunami fragility models. The systematic implementation of the data and methods facilitates the quantitative comparison of tsunami fragility models under different assumptions. Such comparison shows that the binomial logistic method with un-binned data is preferred among the considered models; nevertheless, further investigations related to multinomial logistic regression with un-binned data are required. Finally, the developed tsunami fragility functions are integrated with building damage-loss models to investigate the influences of different tsunami fragility curves on tsunami loss estimation. Numerical results indicate that the uncertainty of input tsunami data is not negligible (coefficient of variation of 0.25) and that neglecting the input data uncertainty leads to overestimation of the model uncertainty.     

海啸及其在核电厂选址中的安全评价

海啸大小的量度应包括关于海啸“源”处大小的描述,“源”处海啸的大小与地壳形变规模和方式有着直接的关系。在海啸与地震的关系中,除了地震震级外,强调了震源破裂方式这一因素。阐述了关于核电厂选址安全评价中历史资料的整理、分析,对未来海啸“源”的预测、海啸传播路径的调查和分析以及综合评价等4个方面进行了讨论     

Tsunamis on the Pacific Coast of Canada Recorded in 1994–2007

In the last 15 years there have been 16 tsunami events recorded at tide stations on the Pacific Coast of Canada. Eleven of these events were from distant sources covering almost all regions of the Pacific, as well as the December 26, 2004 Sumatra tsunami in the Indian Ocean. Three tsunamis were generated by local or regional earthquakes and two were meteorological tsunamis. The earliest four events, which occurred in the period 1994–1996, were recorded on analogue recorders; these tsunami records were recently re-examined, digitized and thoroughly analysed. The other 12 tsunami events were recorded using digital high-quality instruments, with 1-min sampling interval, installed on the coast of British Columbia (B.C.) in 1998. All 16 tsunami events were recorded at Tofino on the outer B.C. coast, and some of the tsunamis were recorded at eight or more stations. The tide station at Tofino has been in operation for 100 years and these recent observations add to the dataset of tsunami events compiled previously by S.O. Wigen (1983) for the period 1906–1980. For each of the tsunami records statistical analysis was carried out to determine essential tsunami characteristics for all events (arrival times, maximum amplitudes, frequencies and wave-train structure). The analysis of the records indicated that significant background noise at Langara, a key northern B.C. Tsunami Warning station located near the northern end of the Queen Charlotte Islands, creates serious problems in detecting tsunami waves. That station has now been moved to a new location with better tsunami response. The number of tsunami events observed in the past 15 years also justified re-establishing a tide gauge at Port Alberni, where large tsunami wave amplitudes were measured in March 1964. The two meteorological events are the first ever recorded on the B.C. coast. Also, there have been landslide generated tsunami events which, although not recorded on any coastal tide gauges, demonstrate, along with the recent investigation of a historical catastrophic event, the significant risk that landslide generated tsunami pose to coastal and inland regions of B.C.     

马尼拉地震带海啸对广东沿海影响的数值研究——潮汐与海啸的非线性作用的影响

基于COMCOT数值模型,建立了天文潮与海啸耦合数学模型,对日本"311"海啸进行了模拟验证。针对马尼拉地震带海啸,通过设计海啸震源的计算,分析广东省沿海海啸风险,从数值上得出了海啸引发的最大增水值以及海啸到达广东省沿岸的时间。