关于地震科学实验场的几个基本问题

“实验” 和 “试验” 之间, “实验场” 和 “试验场” 之间, “中国地震科学实验场” 与其他 “地震科学实验场” ,以及 “科研项目部署在实验场” 和 “实验场的科研项目” 之间,字面意思上的不同可能会直接导致背后指代的含义也不同,这一点通常不会被注意到。本文通过对以上几组词（组）的讨论与对比,期望能够加深对中国地震科学实验场的一些基本但重要问题的科学认识。      

地震预测预报经验的积累

根据《中国震例》所载1966年至1985年以来，全国Ms≥5.0的58次中强地震的《震例》研究成果，从应用的角度出发，探讨了动态跟踪预测未来中强地震活动“时”、“空”、“强”的活动规律，得出如下启示1)利用地震的前兆总体演变过程的阶段性以探讨定量预测其“活动时段”；2)利用地震的前兆总体分布图象以探讨定量预测其“活动空间”；3)利用地震的前兆环的规模以粗略地预估其未来强震的“活动强度”。还初步探讨了利用它们的“场”、“源”演变的关联性，提出文中一些作法的物理意义之所在。     

“韧性”的词义解析及其应用

英文“Resilience”和汉语“韧性”这两个词汇被广泛应用在不同的学科领域。在中国的生态学和工程学领域“Resilience”一词常被翻译成“恢复力、弹性、韧性和韧弹性”等,正确的理解和解析英文“Resilience”和汉语“韧性”十分必要。本文主要依据现有英文和汉语辞典、辞书以及相关的中外科技文献,对英文“Resilience”和汉语“韧性”这两个词汇的含义进行全面的词义辨析和清理,认为英文“Resilience”翻译成汉语“韧性”比较合适,符合汉语的词义和语言环境,韧性在一定程度上涵盖了恢复、弹回和弹性的含义;在此基础上,总结和厘定了韧性的起源、定义和内涵;比较全面的梳理和评述了“Resilience”和“韧性”这两个词在不同学科领域的发展和演化。这一研究工作对正确的使用英文“Resilience”和汉语“韧性”有重要意义,对从事韧性城市研究、城市规划、城市抗震韧性研究和建筑抗震韧性研究的科技人员有一定的参考价值。     

The variation of cosmogenic Kr and Xe in a core from Estherville mesosiderite: direct evidence that the lunar131Xe anomaly is a depth effect

Kr and Xe were measured by a stepwise heating technique in three samples of a drill core in the “Minnesota” fragment of the Estherville mesosiderite. The cosmogenic⁷⁸Kr/⁸³Kr decreased from the “top” sample to the “bottom” sample(“top” = 0.163 ± 0.005, “bottom” = 0.151 ± 0.005) while the cosmogenic¹³¹Xe/¹²⁶Xe ratio increased(“top” = 5.58 ± 0.35, “bottom” = 6.92 ± 0.17). Cosmic-ray track studies have shown that the “top” sample was indeed closer to the preatmospheric surface than the “bottom” sample by ～ 10 cm. This is the first direct evidence, in a sample of known geometry, that the cosmogenic¹³¹Xe/¹²⁶Xe ratio increases as a function of depth, and as such, confirms the hypothesis that the lunar¹³¹Xe anomaly is a bona fide depth effect due to resonance neutron capture in¹³⁰Ba.     

Intraseasonal predictability of the duration of flooding above National Weather Service flood warning levels across the U.S. Midwest

Unpreparedness is often the main cause of the economic and social damages caused by floods. To mitigate these impacts, short-term forecasting has been the focus of several studies during the past decades; however, less effort has been paid to flood predictions at longer lead times. Here, we use forecasts by six models from the North American Multi-Model Ensemble project with a lead time from 0.5 to 9.5 months to predict the seasonal duration of floods above four National Weather Service flood categories (“action,” “flood,” “moderate” and “major”). We focus on 202 U.S. Geological Survey gage stations across the U.S. Midwest and use a statistical framework which considers precipitation, temperature, and antecedent wetness conditions as predictors. We find that the prediction skill of the duration of floods for the “action” and “flood” categories is overall low, largely because of the low accuracy of the climate forecasts rather than of the errors introduced by the statistical models. The prediction skill slightly improves when considering the shortest lead times (i.e., from 0.5 to 2.5 months) during spring in the Northern Great Plains, where antecedent wetness conditions play an important role in influencing the generation of floods. It is very difficult to draw strong conclusions with respect to the “moderate” and “major” flood categories because of the limited number of available events.     

莺歌海盆地“暗点”型气藏地震识别技术研究

莺歌海盆地乐东区深层与东方区具有类似的成藏条件,是高温高压领域获取下一个重大勘探突破的最现实区域.但是该区已钻遇的“亮点”型储层物性差,普遍表现为低孔-特低渗特征,而区域基础规律研究表明,区域潜在甜点储层在地震上应该表现为“暗点”型特征.但是,“暗点”型储层在叠后地震资料上无法有效识别,如何准确预测“暗点”型储层是乐东区勘探新突破的重点攻关方向.本文针对“暗点”识别难的问题,提出了基于叠前地震资料的储层预测技术.从岩石物理出发系统性地梳理该区“暗点”型储层的地球物理特征,总结出其具有“叠加无反射、近道弱波峰、远道弱波谷、道集极性反转”的规律,根据该规律建立了Fstack属性重构算法,利用该算法开展甜点储层筛选并进行“暗点”储层预测,结合道集资料、反演结果等地球物理信息,最终确定潜在“暗点”型气层的分布范围.钻井结果证实该技术对乐东区深层潜在“暗点”型储层具有很好的预测效果.     

Interactions of isolated vortices I: Modons colliding with modons

Abstract

Collisions between isolated(i.e. localized) dipolar vortex states, called modons, are examined in various numerical solutions of the quasigeostrophic, equivalent barotropic equation. For a range of parameters, the collision interactions are soliton-like in that the vorticity maxima are displaced (phase-shifted) with only small speed changes and little excitation of internal degrees of freedom. For other parameters, new “inelastic” effects are observed, including speed changes due to vorticity rearrangement, vorticity filamentation, modon “capture” or “fusion” in an overtaking collision, and the “fission” of a modon into its component vorticity monopoles in a head-on collision.     

The Transition from Three-Dimensional Embedding to Two-Dimensional Euler-Lagrange Deformation Tensor of the Second Kind: Variation of Curvature Measures

Based on the Stein formulation of changes of curvature parameters, we describe the changes of Riemann two-dimensional manifolds of surface geometries. The three-dimensional left and right Euclidean manifolds with the curvature parameters “geodetic curvature, normal curvature, geodetic torsion” characterize the embedding “Riemann to Euclid” or 2d into 3d. The variation in time of the Euler-Lagrange deformation tensor of the second kind, in short “curvature variation” is studied.     

Seismic Precursors to Space Shuttle Shock Fronts

—?Seismic precursors to space shuttle re-entry shock fronts are detected at TXAR in Southwest Texas when the ground track of the orbiter vehicle passes within ～150–200?km of the observatory. These precursors have been termed “shuttle-quakes” because their seismograms superficially mimic the seismograms of small earthquakes from shallow sources. Analysis of the “shuttle-quake” seismograms, however, reveals one important difference. Unlike ordinary earthquakes, the propagation azimuths and horizontal phase velocities of the individual phases of the “shuttle-quakes” are functionally related. From a theoretical model developed to account for the origin of these precursors it is found that the seismic phases of “shuttle-quakes” are “bow” waves. A “bow” wave originates at the advancing tip of the shock front trace (i.e., intersection of the re-entry shock front with the surface of the earth) when the ground speed of the orbiter vehicle exceeds the horizontal phase velocity of a particular seismic phase. “Bow” waves are shown to differ in two important respects from the ordinary seismic phases. They vanish ahead of the advancing tip of the shock front trace and their propagation azimuths and horizontal phase velocities are functionally related. The ground speed of the orbiter vehicle exceeds the horizontal phase velocities of crustal seismic phase over much of the re-entry flight profile. As a result, P,S, and R _g “bow” waves will be seen as precursors to the re-entry shock front at stations located within a few hundred km of its ground track.     

Recent development of the earthquake strong motion-intensity catalog and intensity prediction equations for Iran

This study aims to develop a new earthquake strong motion-intensity catalog as well as intensity prediction equations for Iran based on the available data. For this purpose, all the sites which had both recorded strong motion and intensity values throughout the region were first searched. Then, the data belonging to the 306 identified sites were processed, and the results were compiled as a new strong motion-intensity catalog. Based on this new catalog, two empirical equations between the values of intensity and the ground motion parameters (GMPs) for the Iranian earthquakes were calculated. At the first step, earthquake “intensity” was considered as a function of five independent GMPs including “Log (PHA),” “moment magnitude (M_W),” “distance to epicenter,” “site type,” and “duration,” and a multiple stepwise regression was calculated. Regarding the correlations between the parameters and the effectiveness coefficients of the predictors, the Log (PHA) was recognized as the most effective parameter on the earthquake “intensity,” while the parameter “site type” was removed from the equations since it was determines as the least significant variable. Then, at the second step, a simple ordinary least squares (OLS) regression was fitted only between the parameters intensity and the Log (PHA) which resulted in more over/underestimated intensity values comparing to the results of the multiple intensity-GMPs regression. However, for rapid response purposes, the simple OLS regression may be more useful comparing to the multiple regression due to its data availability and simplicity. In addition, according to 50 selected earthquakes, an empirical relation between the macroseismic intensity (I₀) and M_W was developed.     

Groundwater potential zones using a combination of geospatial technology and geophysical approach: case study in Dehradun,India

ABSTRACT

A combination of geospatial, geophysical and statistical models using satellite data, the weighted index overlay (WIO) method and two-dimensional electrical resistivity tomography (2D-ERT) is applied to generate the highest potential groundwater area and to further explore the groundwater in Dehradun, India. The results show that of 19.7 km² total basin area, 0.26% falls under the “poor” category as a prospect zone for groundwater, 4.3% is “moderate”, 10.10% “moderately good”, 4.9% “good” and 0.17% “very good”. In addition, the demonstration of the geophysical survey is presented, in which Purkal Youth Society Division (PYSD) site is categorized as a shallow aquifer zone and the Guru Nanak Fifth Centenary School (GNFCS) site is a deeper aquifer zone. Our study emphasizes remote sensing and geographic information system integrated with a geophysical survey to support prospecting the most probable area and confirm the existence of groundwater.     

An improved shuffled frog leaping algorithm and its application in the optimization of cascade reservoir operation

ABSTRACT

A new improved shuffled frog leaping algorithm (SFLA), the chaos catfish effect SFLA (CCESFLA), is proposed by coupling a local “refine search” mechanism and a “global incentive adjustment” mechanism. Chaotic technology is introduced in the local “refine search” mechanism to improve local search ability, by implementing more refined local search around the optimal individuals. The catfish effect mechanism is adopted in the “global incentive adjustment” mechanism to improve global convergence, by motivating the frogs to “jump out” of the local steady state. The operation optimization by the CCESFLA is carried out taking the Li Xianjiang cascade reservoirs in China as an example. Compared with SFLA, particle swarm optimization, immune SFLA and cloud SFLA, the average annual power generation using the CCESFLA can be increased by 6.7, 7.5, 3.0 and 0.8%, respectively. The convergence process of the CCESFLA is more stable, and its execution time is the least of the three improved SFLAs.     

Estimation of source function and medium response function by autoregressive method

By modelling seismograms as “low” and “high” order autoregressive (AR) processes, the source function and the medium response function are separated from a single channel seismogram. Akaike's final prediction error is used as a statistic to select the appropriate “low” and “high” AR order of the process. Case studies of synthetic data show that the recovered source and reflectivity functions compare very well with the input functions. Using this method, arrivals of the surface reflected P phases of five explosions from the Soviet region and of two earthquakes from Kamchatka, recorded at Gauribidanur Seismic Array (GBA), India, are identified. Certain features of the source and source region of these events are also inferred.     

The impact of meteorological changes from 2013 to 2017 on PM2.5 mass reduction in key regions in China

Science China Earth Sciences - In 2013, China issued the “Action Plan for the Prevention and Control of Air Pollution” (“Ten Statements of Atmosphere”) and implemented a...     

Soil failure can be used for seismic protection of structures

A new seismic design philosophy is illuminated, taking advantage of soil “failure” to protect the superstructure. Instead of over-designing the foundation to ensure that the loading stemming from the structural inertia can be “safely” transmitted onto the soil (as with conventional capacity design), and then reinforce the superstructure to avoid collapse, why not do exactly the opposite by intentionally under-designing the foundation to act as a “safety valve” ? The need for this “reversal” stems from the uncertainty in predicting the actual earthquake motion, and the necessity of developing new more rational and economically efficient earthquake protection solutions. A simple but realistic bridge structure is used as an example to illustrate the effectiveness of the new approach. Two alternatives are compared : one complying with conventional capacity design, with over-designed foundation so that plastic “hinging” develops in the superstructure; the other following the new design philosophy, with under-designed foundation, “inviting” the plastic “hinge” into the soil. Static “pushover” analyses reveal that the ductility capacity of the new design concept is an order of magnitude larger than of the conventional design: the advantage of “utilising” progressive soil failure. The seismic performance of the two alternatives is investigated through nonlinear dynamic time history analyses, using an ensemble of 29 real accelerograms. It is shown that the performance of both alternatives is totally acceptable for moderate intensity earthquakes, not exceeding the design limits. For large intensity earthquakes, exceeding the design limits, the performance of the new design scheme is proven advantageous, not only avoiding collapse but hardly suffering any inelastic structural deformation. It may however experience increased residual settlement and rotation: a price to pay that must be properly assessed in design.     

地震台站计算机常见故障分析与处置

将地震台站计算机作为探讨目标,分析研究前兆站点计算机经常出现的 “系统死机” “自动关机” 和 “蓝屏” 等故障原因,提出合理有效的解决办法,及时排除故障,有效保障台站计算机的正常运行,这对台站计算机维护管理人员的工作有一定的指导意义。      

Climate variability,hydrology and water resources: do we communicate in the field? (HAPEX,FIFE, GEWEX,GCIP and what next?)

Abstract

All the field “experiments” indicated in the sub-title above include the hydrological cycle in some or all of its aspects and thus require the use of “hydrological sciences”. Is hydrology actually included in them? This depends on the definition of hydrology used. The paper briefly describes the different definitions of “hydrology” in the context of the scientific objectives and concepts of these experiments and related scientific activities. It further evaluates the role actually assigned to hydrologists in past cross-disciplinary endeavours to conduct “field experiments” and goes on to propose adjustments to this role in the GEWEX Continental-scale International Project (GCIP). Related activities are analysed in some detail in this framework and proposals are presented for increased inter-disciplinary communication.     

Analysis of the changing patterns of seasonal flooding along the U.S. East Coast

Ocean Dynamics - Sea level rise (SLR) is causing acceleration in the frequency and duration of minor tidal flooding (often called “sunny-day” or “nuisance” flooding) along...     

“情景-应对”型理论体系的发展及其在地震灾害应急管理中的应用探讨

“情景-应对”型理论体系基于事件静、动态情景分析生成应急决策方案,已成为重大突发事件应急决策的基本范式。近年来,“情景-应对”研究理论的迅速发展极大地拓宽了其应用范围,逐渐被引入地震应急中,在一定程度上能够弥补传统“预测-应对”模式的不足,为震后高效行动及充分应对提供有效支撑。本文从情景识别、情景推演及应对处置方案生成等方面详细介绍了“情景-应对”理论体系发展中涉及的关键技术,阐述了其在地震灾害应急管理中的应用。通过对已有研究的回顾,分析讨论了该领域的最新进展及需进一步解决的问题。