Response of Alum Rock springs to the October 30, 2007 Alum Rock earthquake and implications for the origin of increased discharge after earthquakes

The origins of increased stream flow and spring discharge following earthquakes have been the subject of controversy, in large part because there are many models to explain observations and few measurements suitable for distinguishing between hypotheses. On October 30, 2007 a magnitude 5.5 earthquake occurred near the Alum Rock springs, California, USA. Within a day we documented a several‐fold increase in discharge. Over the following year, we have monitored a gradual return towards pre‐earthquake properties, but for the largest springs there appears to be a permanent increase in discharge. The Alum Rock springs discharge waters that are a mixture between modern (shallow) meteoric water and old (deep) connate waters expelled by regional transpression. After the earthquake, there was a small and temporary decrease in the fraction of connate water in the largest springs. Accompanying this geochemical change was a small (1–2°C) temperature decrease. Combined with the rapid response, this implies that the increased discharge has a shallow origin. Increased discharge at these springs occurs both for earthquakes that cause static volumetric expansion and for those that cause contraction, supporting models in which dynamic strains are responsible for the subsurface changes that cause flow to increase. We make a quantitative comparison between the observed changes and model predictions for three types of models: (i) a permanent increase in permeability; (ii) an increase in permeability followed by a gradual decrease to its pre‐earthquake value; and (iii) an increase of hydraulic head in the groundwater system discharging at the springs. We show that models in which the permeability of the fracture system feeding the springs increases after the earthquake are in general consistent with the changes in discharge. The postseismic decrease in discharge could either reflect the groundwater system adjusting to the new, higher permeability or a gradual return of permeability to pre‐earthquake values; the available data do not allow us to distinguish between these two scenarios. However, the response of these springs to another earthquake will provide critical constraints on the changes that occur in the subsurface and should permit a test of all three types of models.     

Evolution of fluid chemistry during travertine formation in the Troll thermal springs,Svalbard, Norway

Arctic hydrothermal springs at Bockfjorden, Svalbard, have isotope and trace element signatures indicative of derivation from glacial melt waters with minor contribution from seawater. Downstream gradients in water chemistry, isotopic composition and carbonate precipitation rates have been documented for the Troll spring and travertine terrace system. The main controls on the downstream evolution of these parameters are carbon dioxide degassing, calcite precipitation, evaporation and biological activity. The carbonate precipitation rates not only show an approximately parabolic dependence on the calcite supersaturation levels, but depend also on local hydrodynamics. Downstream loss of light isotopes of oxygen and hydrogen can be explained as an effect of evaporation, as estimated using chloride as a conservative marker. Biological activity affects nitrate and bromide concentrations and influences the morphology of calcite precipitates.     

What do aqueous geothermometers really tell us?

The application of chemical geothermometry to shallow groundwaters or spring discharge assumes that there is minimal mixing or re-equilibration of water as it travels from depth to the surface. In this study, we examine the potential for mixing and re-equilibration by examining heat and fluid flow along crustal-scale faults in tectonic geothermal systems. Numerical modeling results indicate that maximum in situ temperatures could be under-predicted by up to 30% due to mixing of fluids that enter the fault at different depths. This, coupled with the depression of isotherms by downward groundwater flow in the hanging wall, could cause underestimates of maximum circulation depth of greater than 80% in extreme cases. Kinetics does not favor re-equilibration in the shallower portions of faults due to low temperatures and higher fluid velocities. However, in areas of deeper circulation or higher heat flow such reactions are possible.     

《人民日报》汶川大地震报道框架理论分析

《人民日报》关于汶川地震的报道是一次成功的灾难报道。本文试从框架理论的角度,以《人民日报》关于汶川地震的报道为例,探讨媒体对灾难报道的重大突破。本文运用框架理论,详尽而具体地分析《人民日报》在汶川地震发生后一个月内的所有报道,试从研究中发现《人民日报》是如何在报道中再现＂汶川大地震＂这次突发性公共事件,以及《人民日报》是如何设置这次突发性公共事件的报道框架,以为今后媒体在面对重大突发性公共事件时公如何树立正确的新闻框架提出建议。     

震后赴川入境旅游者满意度评价研究

本文以震后赴川入境旅游者为研究对象,采用因子重要性排序、配对样本t检验及重要性-绩效感知模型揭示了震后赴川入境旅游者的真实满意度感知。研究显示,入境游客对四川旅游经历的整体满意度较高;地震遗迹、大熊猫诸因子期望值与满意度之间的距离存在较大的差距,在排除前期望值过高的干扰后,得出大熊猫因子最终满意度较高的结论;民俗文化、历史文化、自然景观、当地人友善度为主要吸引要素;多数因子的重要性及满意度均较高,仅有城市基础设施一项因子重要性低而评价高,没有因子的重要性高而评价低。     

Groundwater discharges in the Baltic Sea: survey and quantification using a schlieren technique application

Groundwater seeps are known to occur in Eckernförde Bay, Baltic Sea. Their discharge rate and dispersion were investigated with a new schlieren technique application, which is able to visualize heterogeneous water parcels with density anomalies down to Δσ_t = 0.049 on the scale of millimeters. With the use of an inverted funnel, discharged fluids can be captured and the outflow velocity can be determined. Overall, 46 stations could be categorized by three different cases: active vent sites, seep‐influenced sites, and non‐seep sites. New seep locations were discovered, even at shallow near‐shore sites, lacking prominent sediment depression, which indicate submarine springs. The detection of numerous seeps was possible and the groundwater‐influenced area was defined to be approximately 6.3 km². Flow rates of between 0.05 and 0.71 l m^?2 min^?1 were measured. A single focused fluid plume, which was not disturbed by the funnel was recorded and revealed a flux of 59.6 ± 20 ml cm^?2 min^?1 and it was calculated that this single focused plume would be strong enough to produce a flow rate through the funnel of 1.32 ± 0.44 l m^?2 min^?1. The effect of different seep‐meter funnel sizes is discussed.     

汶川地震导致的壁画文物震害研究——以广元市觉苑寺大雄宝殿壁画为例

为保护壁画文物,以四川省广元市剑阁县大雄宝殿为例,对汶川地震作用下殿内壁画的震害进行了研究.根据震后勘查结果,讨论了大雄宝殿壁画的典型震害症状,分析了古建筑侧脚构造对壁画抗震的有利影响.根据大雄宝殿壁画加固工艺作法及古建筑榫卯连接特点,建立了大雄宗殿的震前有限元模型.为研究汶川地震作用下壁画的震害特征,首先对其进行了模态分析,然后将模拟汶川地震波进行调幅,然后作用于大雄宝殿进行地震反应分析.通过采用时程分析法,获得了地震作用下不同时刻壁画整体的内力与变形响应峰值,并获得了典型节点的地震响应曲线.结果表明:大雄宝殿壁画开裂与空鼓的主要原因是面层与墙体粘结不牢导致的受拉破坏;地震作用下壁画保持稳定的振动状态;为提高壁画的抗震性能,壁画木框与外墙板间应加强连接,并在空隙处填塞隔震材料,同时应加强壁画本身保养工作.     

公共危机管理语境中的我国政府能力评析——以汶川抗震救灾危机管理为例

政府领导者的决策能力、政府体系的决策执行能力和政府动员社会支援能力是现代政府能力结构的基本要素。公共危机管理使政府在非常态行政环境中的政府能力充分“曝光”,成为检验一个国家政府能力强弱的最好机会。中国政府正是凭籍强大的政府能力优势,成功地应对了汶川地震危机。这种强政府能力具体体现为：中国政府领导者强大的决策能力、中国政府体系高效的决策执行能力、充足的动员社会支持能力。     

Sampling and analysis of geothermal fluids

Sampling of geothermal fluids presents some problems not encountered when sampling surface and nonthermal ground waters. Specific collection techniques are required to obtain representative samples because of the elevated temperature and boiling of these fluids, the effect of exposing them to the atmosphere and cooling of the samples. Sample treatment during collection depends on the analytical method to be used. When sampling wet‐steam wells, both the liquid and the vapour fractions should be collected at the same fluid separation pressure. When sampling fumarole steam, maximum information is obtained if the total discharge is collected into a single container without separating the gas and the steam condensate fractions. Silica polymerization affects the solution pH. The only way to obtain reliable pH measurement of a water sample supersaturated with respect to amorphous silica is to measure it on site, before the onset of polymerization. This paper provides an outline of the geothermal sampling techniques and analytical methods currently in use in Iceland. Sampling of hot‐water and wet‐steam wells is described, as is sampling of hot springs, fumaroles and gas bubbling through hot‐spring waters. Detailed procedures are given for the analysis of total carbonate carbon and total sulphide sulphur in geothermal water and steam condensate samples.     

社区人文社会环境对汶川地震移民社会适应的影响——以北川县为例

对汶川地震移民来说,社区人文社会环境直接影响他们的社会适应状况。本文基于调研数据,构建模型来探究社区人文社会环境对移民社会适应的影响。研究表明：社区人文社会环境下的16个单一指标,仅\"社区治安\"和\"干群关系评价\"对移民的社会适应状况有显著影响;但16个单一指标集成的4个综合指标-\"配套设施\"、\"邻里关系\"、\"干群关系\"和\"观念习俗\",却均对地震移民的社会适应状况影响显著,并且除\"观念习俗\"与移民的社会适应程度呈弱显著的负相关关系外,其他3个综合指标与移民的社会适应程度都呈强显著的正相关关系。     

Permeability of continental crust influenced by internal and external forcing

The permeability of continental crust is so highly variable that it is often considered to defy systematic characterization. However, despite this variability, some order has been gleaned from globally compiled data. What accounts for the apparent coherence of mean permeability in the continental crust (and permeability–depth relations) on a very large scale? Here we argue that large‐scale crustal permeability adjusts to accommodate rates of internal and external forcing. In the deeper crust, internal forcing – fluxes induced by metamorphism, magmatism, and mantle degassing – is dominant, whereas in the shallow crust, external forcing – the vigor of the hydrologic cycle – is a primary control. Crustal petrologists have long recognized the likelihood of a causal relation between fluid flux and permeability in the deep, ductile crust, where fluid pressures are typically near‐lithostatic. It is less obvious that such a relation should pertain in the relatively cool, brittle upper crust, where near‐hydrostatic fluid pressures are the norm. We use first‐order calculations and numerical modeling to explore the hypothesis that upper‐crustal permeability is influenced by the magnitude of external fluid sources, much as lower‐crustal permeability is influenced by the magnitude of internal fluid sources. We compare model‐generated permeability structures with various observations of crustal permeability.     

汶川地震导致的古建筑震害

为了解汶川地震造成的古建筑震害及对古建筑的保护,根据古建筑震害资料,通过归纳方法,获得了古建筑不同的震害症状：对木结构而言,主要有地基破坏、柱底侧移、柱身倾斜、节点拔榫、装修开裂、梁架歪闪、瓦件掉落、填充墙破坏等;而砖石及砖木结构由于承重材料的抗拉、压、剪强度相对较差,容易产生倒塌等严重震害。在此基础上,通过勘查分析方法,获得了古建筑产生震害的主要原因：地震力过大、古建筑缺乏及时保养与加固、施工原因及砖石材料本身强度差的原因等。针对不同的震害原因,提出了相应的抗震加固建议。在上述工作基础上,得出如下结论：为提高古建筑的抗震性能,应加强对古建筑的维护与加固,及时清除各种隐患,将地震产生的破坏减小到最轻的程度。     

Geodynamically induced variations in the emission of CO2 gas at San Faustino (Central Apennines,Italy)

The Central Apennines are affected by frequent earthquakes of moderate magnitude that occur mainly within the upper part of the crust at depths of <15 km. A large number of cold gas emissions that are rich in CO₂ are also found in the region. One particular vent with a high rate of degassing was equipped with a sensor to measure flow rates, which were recorded for a number of different periods between 2005 and 2010. Factors that could affect potentially CO₂ flow rates include barometric pressure, atmospheric temperature, precipitation and local seismicity. Our analysis indicates that the periods of anomalous flow rate were related not to the environmental factors but probably to the deformative processes of the crust associated with the local seismicity. Local seismic events as expression of geodynamic processes occurred always before and during these anomalous gas flow periods. This correlation exists only for events that occurred eastwards of the gas emission site close to the Martana fault zone. We herein consider this correlation as indication for a continuous interaction between the field of static strain and the deep fluid pressure. An approximation of the fluid pressure transmission towards the gas emission site gives reasonable values of 1–10 m² sec^?1. To make comparisons with the long‐term effects of the static strain, we also recorded the short‐term effects of the dynamic release of strain induced by the series of strong earthquakes that took place in L’Aquila in 2009. We detected a significant anomalous flow rate that occurred at the same time as this seismic sequence, during which widespread degassing was induced around the focal zone.     

基于集体记忆的震后北川老县城空间重构

汶川地震重灾区北川老县城为案例地,以地震受灾群体老县城居民为研究样本,通过问卷调查与访谈挖掘灾后遗址唤起居民的集体记忆和空间,通过认知地图和GIS空间分析对比遗址官方记忆空间、居民集体认知-情感空间、行为空间的差异,揭示现实空间与居民集体记忆空间互动影响机制。灾后日常记忆、灾难记忆夹杂在一起,产生怀旧、创伤等情感,构成居民复杂的集体记忆。尽管具体空间引发的情感以负面为主,但居民对老县城整体还是充满了积极的地方依恋和认同。     

Seismic History of the Church of San Pietro Di Coppito in L’Aquila

After the terrible 18th-century earthquakes—in L’Aquila in 1703, Lisbon in 1755, and Reggio Calabria in 1783—specific anti-seismic precepts were introduced in the rules of the art of masonry construction. Scrupulously adhered to in the first years after the earthquake, those precepts gradually ceased to be used until they were almost completely forgotten, centuries later, by which time the earthquake had become a distant memory. The church of San Pietro di Coppito, one of the most important churches of L’Aquila, is emblematic of this singular process. Deeply transformed in accordance with new anti-seismic construction techniques after it was particularly badly damaged in the terrible 1703 earthquake, the church was subjected, in the 1970s, to drastic alterations by the Commissioner Mario Moretti, who demolished all the baroque additions and redesigned it in the “medieval Abruzzo” style, eliminating in the process the intelligent anti-seismic provisions introduced in the 18th century. In addition to documentary purposes, this work aims to underline the effectiveness of this early 18th-century example of anti-seismic engineering in the belief that the constructive solutions it employed could still form a valid architectural and structural model in view of the massive restoration task for which, unfortunately, L’Aquila is still waiting today.     

5.12汶川地震中四川可移动文物及其建筑受损情况调查

四川省文博单位所藏大量可移动文物在5.12汶川地震中遭受不同程度损毁,其受损原因极具研究价值。采用文物受损信息调查表、实地调查与再核实、数据统计与分析等方法,针对受损可移动文物所处大环境、小环境及其存放或展示方式,结合每件可移动文物的受损状态进行统计研究。基本探明汶川地震中文博单位建筑和可移动文物受损原因和类型,为提升文博工作者的文物防震保护意识和开展文物防震保护研究提供基础资料。