利用远震接收函数反演重庆地震台下方的速度结构

选取重庆地震台2010年至2012年记录的60个远震宽频带数字地震记录,采用频率域反褶积法获得台站的接收函数,采用H-Kappa叠加方法反演台站下方的地壳厚度和泊松比,作为台站下方波速反演的约束条件,以减少反演的非唯一性.计算结果显示,重庆地震台下方地壳厚度为42 km,与中国大陆中西部地区Moho面深度在38-45 km保持一致.该研究对增强该区的深部地质构造特征、分析孕震机制等具有积极意义.     

利用接收函数研究延边地震台下方地壳结构

收集整理2007年以来延边地震台记录的113个远震数字波形资料,采用远震接收函数反演延边地震台下方地壳结构,运用H-Kappa叠加方法,计算得到台站下方地壳厚度和泊松比.采用全球平均地壳模型作为初始模型,反演台站下方0-100 km的S波速结构.反演结果表明,延边地震台下方地壳厚度为30.8 km,波速比为1.84,泊松比较高,为0.29.在台站下方15-20 km及25-30 km处存在低速层.     

八五三地震台地壳结构与泊松比浅析

整理收集2017年1月—2018年9月八五三地震台记录到的远震地震事件,采用频率域反褶积方法提取P波径向接收函数,运用H-Kappa叠加方法反演台站下方地壳厚度及壳内物质泊松比.结果表明:八五三地震台下方的地壳厚度为34.6km,泊松比值较低,为0.226;反映了台站下方地壳物质岩性二氧化硅含量较高,熔融度低的长英质岩...     

华东及安徽地区断裂构造及分形分析

根据安徽台网25个台站记录到的远震波形资料,运用频率域反褶积的方法提取接收函数,并采用H-Kappa扫描法反演得到安徽地区各个台站下方的地壳厚度与纵横波速度比。结果显示,安徽地区台站下方地壳厚度大致可分为3个区域：皖西南大别山地区、皖南山区和淮河以北的皖北平原地区,其中大别山地区台站下方的地壳厚度位于35—39 km范围内,相对较厚;皖南地区位于33—36 km范围内;皖北以平原为主,地壳厚度位于30—33 km范围内。这一研究结果与安徽地区的地质构造背景具有较好的相关性。同时,H-K扫描结果显示,安徽地区台站下方波速比基本处于1.70—1.80范围内,变化不大。在界面倾斜角度不大的前提下,利用横向均匀分层模型的波形反演实现接收函数的波形拟合,得到台站下方地壳上地幔S波速度结构,计算结果显示,安徽地震监测台站下莫霍面上表面S波速度一般为3.6—3.9 km/s,而界面底部大约为4.3—4.6 km/s,莫霍面处的速度起伏变化并不十分明显。     

利用接收函数反演安徽地区地壳S波速度结构

根据安徽台网25个台站记录到的远震波形资料,运用频率域反褶积的方法提取接收函数,并采用H-Kappa扫描法反演得到安徽地区各个台站下方的地壳厚度与纵横波速度比。结果显示,安徽地区台站下方地壳厚度大致可分为3个区域:皖西南大别山地区、皖南山区和淮河以北的皖北平原地区,其中大别山地区台站下方的地壳厚度位于35—39 km范围内,相对较厚;皖南地区位于33—36 km范围内;皖北以平原为主,地壳厚度位于30—33 km范围内。这一研究结果与安徽地区的地质构造背景具有较好的相关性。同时,H-K扫描结果显示,安徽地区台站下方波速比基本处于1.70—1.80范围内,变化不大。在界面倾斜角度不大的前提下,利用横向均匀分层模型的波形反演实现接收函数的波形拟合,得到台站下方地壳上地幔S波速度结构,计算结果显示,安徽地震监测台站下莫霍面上表面S波速度一般为3.6—3.9 km/s,而界面底部大约为4.3—4.6 km/s,莫霍面处的速度起伏变化并不十分明显。     

利用远震接收函数研究辽宁地区的地壳厚度及泊松比

文中利用辽宁省数字地震遥测台网15个台站记录的远震P波波形资料,用频率域反褶积方法提取接收函数,由H-Kappa叠加方法得到了各台站下方的地壳厚度和泊松比。研究结果表明,辽宁地区的地壳泊松比在0.25～0.29之间,地壳厚度介于31～36km之间,东部褶隆带的地壳厚度从北向南由31km增至35km。松辽构造盆地地壳厚度变化不大,平均厚度为31km。辽西褶隆带与东部褶隆带的地壳厚度均比哈尔滨构造盆地厚约2～4km     

利用远震接收函数反演山西地区台站下方的地壳厚度及泊松比

利用2008—2013年山西数字地震台网远震宽频带记录波形资料,运用H-Kappa叠加方法得到各台站下方的地壳厚度和波速比。研究结果表明,山西地区地壳厚度存在明显的差异。研究区内地壳平均厚度约39km,南北地壳厚度变化幅度较大,其中SHZ(上皇庄台)地壳厚度最大为43km,ANZ(安泽台)地壳厚度最小为36km,南北两端差异达7km。泊松比值在0.24~0.31之间变化,与全球的泊松比估计值相当。山西的地壳厚度与地表地形存在着明显正相关,而地壳厚度和泊松比则呈现负相关的关系。     

利用远震接收函数反演陕西地震台站下方的地壳厚度

文中利用陕西数字地震遥测台网14个遥测子台记录的远震波形资料,用频率域反褶积方法提取接收函数,由H-Kappa叠加方法反演得到各台站下方的地壳厚度和泊松比。在此基础上结合相关地震构造文献,对陕西地区的地壳特征进行了分析,并讨论了陕西地震活动与地壳结构、地质构造之间的关系。研究结果表明:1)陕西地区的地壳总体趋势是东薄西厚,陕西南部和北部地区地壳较厚(≥40km),位于陕西中部的渭河盆地地壳较薄(34～40km);14个台站中,渭河盆地东部与山西交界的华阴台下方地壳厚度最薄(34km),而盆地西北端的陇县台位于六盘山余脉上,地壳厚度最厚(48km)。2)陕西地区泊松比值总体变化不大(0.24～0.29),可能表明这一地区的岩石组成以中度组分为主;以渭河盆地为界,向北靠近地台一侧泊松比值相对较高,向南靠近秦岭山脉一侧则比值相对较低。3)地震活动与地质构造之间存在内在的联系。渭河盆地处于几个构造体系的复合部位,属于强地震的多发区;陕西南部地区的地震活动相对较弱,主要发生在汉中盆地和安康盆地,受陕南几条主要断裂控制;陕西北部地区地质构造相对稳定,地震活动最弱。泊松比反映了地球内部的物质构成,分析认为其与地震活动存在一     

利用远震接收函数探测襄樊台下方地壳厚度及泊松比

利用襄樊台2015—2018年记录的震中距30°—90°,震级5.5级以上(含5.5级)的高信噪比远震波形事件,通过时间域反褶积方法提取台站接收函数,并用H-k扫描叠加方法得到台站下方地壳厚度和波速比。结果表明,襄樊台下方地壳厚度为35 km,略高于大陆地壳平均厚度33 km,处于西部山区厚地壳与中东部薄地壳的过渡地带。泊松比偏低,存在因区域内地壳应力积累发生微小地震的可能性。     

普洱、西双版纳地区的速度结构研究

利用接收函数方法对2008年普洱、西双版纳区域内6个台站接收到的远震数据进行反演,得到该研究区域内台站下方的速度结构.结果表明:景谷、思茅台下方的莫霍面深度在36km左右,区域南部的孟连、澜沧、勐腊台下方的地壳厚度有轻微变薄现象,为32km,景洪台下方地壳厚度最薄,仅为30km.     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

Earthquake Engineering and Engineering Vibration Aims And Scope

正This journal is established by the Institute of Engineering Mechanics(IEM),China Earthquake Administration,to promote scientific exchange between Chinese and foreign scientists and engineers so as to improve the theory and practice of earthquake hazards mitigation,preparedness,and recovery.To accomplish this purpose,the journal aims to attract a balanced number of papers between Chinese and     

Foreword

Destructive earthquakes have caused great damage in China and the United States and collapsing buildings havecaused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence ofearthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structuresduring earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant,and finally, how to cope with earthquake damage and restore a city to normal functioning. Such efforts are in progressin both countries, but unfortunately, the language barrier interferes with the free flow of information between China andthe Untied States. It would be mutually beneficial if some means could be developed to promote the exchangeof information across the Pacific Ocean. This new journal has been established for this purpose and its success willbe an important step in promoting earthquake engineering in China and the United States.     

WORLD ASSOCIATION FOR SEDIMENTATION AND EROSION RESEARCH(WASER)

正President:Giampaolo Di Silvio,Italy Vice Presidents:Ulrich C.E.Zanke,Germany Zhao-yin Wang,China The World Association for Sedimentation and Erosion Research(WASER),inaugurated on Oct.19,2004,is an independent non-governmental,non-profit organization.The mission of WASER is to promote international co-operation on the study     

Enhancing remote sensing research on global change to improve our understanding on Earth system processes

正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases     

Solute concentrations in the lower niger river and the source rock contribution

Water quality analyses for the Niger River for the 1980/81 hydrological year are presented. The samples were collected from the main river at Lokoja, and from two main tributaries, the Kaduna and the Benue Rivers. Different water types were distinguished by the concentrations of major ions. The type Ca > Na > Mg > K - HCO₃ > SO₄ > Cl was represented at all stations during at least part of the year. Chloride was found to dominate the sulphate ion in the Kaduna and Niger, while the Benue maintained a higher concentration of sulphate relative to chloride all year round. Distinct patterns of seasonal variation in the ion concentrations were observed, particularly for the samples collected at Lokoja. Low ion concentrations were prominent during periods of high discharge, while low flow periods coincided with high dissolved ion concentrations. The contribution of rainwater to the total dissolved solids in the river waters was assessed indirectly using rainwater chemistry data from the Gulf of Guinea. The estimated rainwater contribution to the Lower Niger amounts to 5.15 mg 1^?1. Geochemical weathering calculations involving reactions of the four major minerals of granitic rocks - anorthite, biotite, albite, and K-feldspar - with carbon dioxide and water, can account for the average water composition of the Lower Niger. The proportion of the ionic components was also related to the occurrence of the respective element in the minerals.