Crustal velocity structure of the Shaowu-Nanping-Pingtan transect through Fujian from deep seismic sounding-tectonic implications

The Shaowu-Nanping-Pingtan deep seismic sounding profile is located in northern Fujian Province. High-quality seismic sounding data were acquired by five large explosive blasts received by 133 digital seismic instruments along the profile. Based on seismic facies analysis and travel-time picking on shot record sections, a model of the velocity structure of upper crust was developed by finite-difference tomography of the first breaks; the 2-D P-wave velocity structure and tectonic characteristics of the crust were interpreted further by fitting of waveforms and seismic travel times. The results show that the top of the crystalline basement is buried at depths of 2.0–4.0 km, with the deepest buried up to 4.0 km within the Fuzhou Basin. The Moho interface was found to be deeper in the west and shallower in the east(i.e., 30.0 km near the coast, increasing to 33.0 km northwestward). The lower crust on the east side of the Zhenghe-Haifeng Fault Zone has a smoothly varying gradient structure, whereas on the west side it has two distinct layers with a boundary between those layers at a depth of 23 km. Seismic velocities on the west side are generally lower than on the east side; a low velocity layer is observed with a lowest speed of 6.25 km/s at a depth of 22 km on the west side, which may consist of partially molten material. The Zhenghe-Haifeng Fault is a deep crustal fault, and should be a channel for deep material upwelling; it has a direct relationship with multiple stages of continental tectonic movements in Southern China and with multiple magmatic events that started in the Proterozoic and ended in the of late Tertiary in Fujian.     

西岭雪山滑雪场秋冬旅游降雪预报研究

利用大邑、西岭雪山滑雪场及周边区域自动站2005～2017年每年10月～次年2月逐日最低温度资料,通过统计分析区域自动站与大邑站候平均最低温度差值,建立以大邑本站最低温度预报值为基础,加上逐候最低温度差值后得到区域各站的日最低温度预报的候最低温度差值订正方法;用距滑雪场最近的格点温度预报数据代替滑雪场站点温度预报,选出最低温度,以气温预报变化量,建立最低气温预报的模式温度订正方法;建立以候最低温度差值订正和模式温度订正进行加权平均的最低温度集成订正方法。通过对以上三种最低温度预报方法进行检验,发现最低温度集成订正方法预报准确率最高。基于最低温度集成订正方法预报西岭雪山滑雪场的最低温度,结合智能网格降水预报结果和降雪最低温度阈值判别,建立西岭雪山降雪的订正预报方法。     

辽宁区域性春旱的大气环流及影响因子分析

利用美国NCEP/NCAR的再分析资料、Hadley中心逐月海温资料(HadiSST)和辽宁地区逐日降水资料,对辽宁区域性春旱大气环流特征及影响因子进行分析。结果表明：乌山脊和东亚大槽减弱,位相比历年平均位相偏东,中高纬大气环流经向度减小,是导致中国辽宁区域性春季降水减少的大气环流背景;区域性春旱同期,大陆气压升高,海上气压降低;辽宁上空湿度明显小于历年均值,贝湖到中国辽宁一带盛行西北气流。区域性春旱前冬,辽宁上空200hPa高度场出现正距平;地面气温较历史同期偏高;Nino3海温异常偏低。     

二郎山公路隧道岩爆特征与预测研究

根据二郎山公路隧道施工中记录的200多次岩爆资料,总结隧道的岩爆特征,并采用"地质超前预报法"和"σθ/Rb判据现场测定预测法"两种方法,对岩爆预测问题进行有益探讨.     

Comparison of two types of persistent heavy rainfall events during sixteen warm seasons in the Sichuan Basin

本文筛选出四川盆地西部(盆西型)和盆地东部(盆东型)持续性暴雨个例,深入对比两类持续性暴雨的大气环流特征和直接造成持续性暴雨的西南低涡维持的机理.四川盆地的短波槽和西太平洋副热带高压的配置有利于持续性暴雨的维持,盆东型的降水强度较盆西型个例强,高空急流位置偏南,南亚高压的强度更强,高层辐散更强,对流层中层副热带高压偏东偏南.盆西型的水汽输送主要来自南海,而盆东型的水汽输送主要来自南海和孟加拉湾.合成涡度收支的结果表明散度项是两类持续暴雨中西南涡维持的主要原因,但盆西型中,垂直平流的作用更强.     

Tracing origins of sewage and organic matter using dissolved sterols in Masan and Haengam Bay,Korea

Masan and Haengam Bays in Korea are highly polluted and semi-enclosed. Domestic and industrial effluents are directly or indirectly discharged into the bays through sewage treatment plants (STP) and creeks. In this study, 15 dissolved sterol compounds were determined in order to understand their sources and relative contribution. Freshwater samples were taken from 13 creeks and at two STP sites on a monthly basis. Total dissolved sterol concentrations ranged from 993 to 4158 ng/L. The concentrations of sterols in winter were higher than in summer. Among the sterols analyzed, cholesterol, β-sitosterol, coprostanol and cholestanone were major compounds in creek water. Seawater samples were concurrently collected at 21 stations in Masan Bay. Total sterol concentrations ranged 118–6,956 ng/L. Inner bay showed high concentrations of sterols in summer, while outer bay showed high sterol concentrations in winter. Among the sterols, cholesterol, β-sitosterol and brassicasterol were major compounds in seawater. In order to examine the contribution of urban sewage, the concentration of coprostanol and fecal sterol ratios were calculated. Most of the creek water, inner bay and near STP outlet samples were affected by sewage. Terrestrial organic matters accounted for a high proportion of dissolved organic matter origin. Fecal origins were relatively high in the inner bay areas and in the STP outlet, while sterols of marine origin were high in the outer bay areas.     

基于网络环境的台站地震速报系统研制与应用

介绍了在网络环境下台站地震速报系统研制的相关技术和流程,阐述了速报系统功能模块的作用和C/S编程实现方法.该系统在安徽省地震台站投入使用以来,替代了台站过去的电话速报方式,为加强台站地震速报质量管理和工作责任起到积极促进作用,收到了预期的效果.     

Undrained monotonic shear behavior of marine soft clay after long-term cyclic loading

Abstract

In the coastal area, nearshore and offshore structures have been or will be built in marine soft clay deposits that have experienced long-term cyclic loads. Therefore, the mechanical behavior of marine clay after long-term cyclic loading needs to be investigated. In this research, a series of monotonic and cyclic triaxial tests were carried out to investigate the postcyclic mechanical behavior of the marine soft clay. The postcyclic water pore pressure, shear strength and secant stiffness are discussed by comparing the results with the standard monotonic test (without cyclic loading). It is very interesting that the postcyclic behavior of marine soft clay specimen is similar to the behavior of overconsolidated specimen, that is, the specimen shows apparent overconsolidation behavior after long-term cyclic loading. Then relationship between the overconsolidation ratio and the apparent overconsolidation ratio is established on the basis of the theory of equivalent overconsolidation. Finally, a validation formula is proposed which can predict the postcyclic undrained shear strength of marine soft clay.     

Fine particulate organic matter transport dynamics in a small Coastal Plain stream: influence of hydrology and channel morphology

Fine particulate organic matter (FPOM) represents a major component of stream organic matter budgets, and its dynamics greatly affect the productivity and metabolism of a stream community. FPOM transport dynamics has been well documented in high-gradient streams with rocky substrates, but information from low-gradient, sandy-bottom streams has been lacking. We estimated FPOM retention patterns in Payne Creek, a 2nd order Coastal Plain stream (USA), under naturally varying hydraulic conditions (discharge and velocity). Corn pollen, as an FPOM analogue, was released along with a conservative solute tracer and the particle retention coefficient (k _p) was calculated by fitting the ratio of total pollen remaining in the water column against the longitudinal transport distance to an exponential decay model. Pollen k _p (n = 4) ranged from 0.034 to 0.214 /m, and particle transport distance (S _p) ranged from 4.7 to 29.7 m. The S _p measured in Payne Creek was in the lowest range of previously reported values, and such rapid particle retention was attributed to the low channel slope and slow current velocity. S _p was significantly correlated to water velocity and the channel friction factor, but not to discharge (Q). Two summer experiments conducted in contiguous stream segments resulted in the shortest (4.7 m) and longest (29.7 m) S _p, despite the similar Q. This was attributed to the segment-scale channel alterations that occurred during the previous winter, which led to very different hydraulic conditions in the two stream segments. In Payne Creek, seasonal changes in hydrology and segment-scale variation in channel morphology were the main factors controlling FPOM transport and retention.     

营口-潍坊断裂带的新构造和新构造活动

裂带是郯庐断裂带通过渤海的部分.郯庐断裂带是我国东部一条规模巨大的NNE-NE向构造带,具有长期发育的历史,新近纪以来的新构造活动相当强烈,尤其是位于渤海的营潍断裂带.但因以前渤海石油地质勘探和研究注重古近纪的地层和构造,而有关新近纪以来的地质资料甚少,致使它成为郯庐断裂带新构造和新构造活动研究程序最低的部分.