Infrasound Radiated During the Montana Earthquake of 1959 August 18

Summary Seismic waves caused by earthquakes radiate infrasound into the atmosphere as they proceed over the Earth's surface. Several instances of such sound waves radiated locally by seismic waves passing through the Washington, D.C., area have been observed at the infrasonic station there. A notable instance was the great Montana earthquake of 1959 August 18. Measurements of the radiated infrasound gave data on the seismic waves, including their travel times, local speeds, directions of travel, amplitudes, and waveforms.     

四硼酸十八铝晶须制备实验中的原料和产品分析

本文报道了在四硼酸十八铝晶须材料制备实验中，原料明矾、脱水明矾和硼酸，以及制成品四硼酸十八铝晶须的熔样处理和分析方法，同时给出有关分析结果。     

汶川地震区暴雨滑坡泥石流活动趋势预测

汶川大地震发生后,暴雨又激发了新的滑坡和泥石流发生.为探讨汶川地震区暴雨滑坡泥石流活动趋势,对比分析了日本关东大地震和台湾集集大地震后诱发滑坡和泥石流活动趋势,在此基础上,对汶川地震区未来滑坡、泥石流活动趋势作了预测分析.同时,还讨论了估算不同强度降雨条件下滑坡面积和泥石流冲出量的方法.初步研究表明,汶川强震区至少在近10 a内,滑坡和泥石流活动趋势是强烈的,之后地质条件将逐渐趋于稳定.本研究选择了面积为5.9 km2的北川县城西侧斜坡为研究区,计算结果是如果一旦遭遇100 a一遇降雨,新增滑坡面积可达166.97 ×104 m2,约占整个研究区流域面积的28.3%.本研究还预测了魏家沟、苏家沟流域的不同频率降雨条件下的泥石流土砂产量,在100 a一遇降雨条件下,泥石流土砂产量分别达71.0×104 m3和49.2×104 m3.研究成果为进一步认识汶川地震区后续降雨作用诱发的滑坡泥石流活动趋势提供参考.     

A Preliminary Investigation into the Relationship between Long-Period Seismic Noise and Local Fluctuations in the Atmospheric Pressure Field

Summary The displacement response of an elastic half space to a plane pressure wave is examined in order to establish the conditions under which sources of this type can contribute significantly to the long-period seismic noise field. The study is restricted to pressure waves which propagate at velocities well below the seismic wave velocities characteristic of the half space. The numerical studies indicate that pressure waves with amplitudes of 100 μbar or more can contribute significantly to the long-period vertical background noise observed at the surface, provided that the detectors are located on sections of alluvial fill or poorly to moderately indurated sandstones and shales whose thicknesses are greater than about a kilometre. These same waves can also create significant tilt noise on long-period horizontal seismographs located at or near the surface, regardless of the rock type. The seismic disturbances created by pressure waves decay rapidly away from the surface. Therefore, it appears that it may be possible to eliminate the effects of atmospherically generated noise by placing the detectors at moderate depths.     

Raw materials activities of the manhattan project on the colorado plateau

The Manhattan Project was a highly secret project during World War II to develop the atomic bomb, and included the acquisition of raw materials. It was carried out by the Army’s Corps of Engineers Manhattan Engineer District. In the United States, 2,698,000 pounds of uranium oxide were acquired at various vanadium mills on the Colorado Plateau, mainly from the treatment of tailings. Geologic investigations conducted by a contractor, Union Mines Development Corporation, laid the ground work for the exploration activities of the Atomic Energy Commission which succeeded the Manhattan Engineer District in 1947     

Preliminary Results on the 3-dimensional Seismic Structure of the Lithosphere under the USGS Central California Seismic Array

About 1500 readings of teleseismic P -time residuals obtained from the US Geological Survey seismograph network in central California have been used to obtain a three-dimensional image of seismic velocity anomalies for this area by the method of Aki, Christoffersson & Husebye We found that the California network is less suitable than the LASA and NORSAR arrays for this kind of studies because of its greater proportion of peripheral blocks in which the resolution is very poor for the stochastic inverse solution and the random error effect is severe for the generalized inverse solution. Nevertheless, the resultant velocity anomalies show a remarkable correlation with the San Andreas fault zone to a depth of 75 km. The anomaly pattern changes drastically as the depth exceeds 75 km, suggesting that the asthenosphere has been reached.     

有关汶川地震及次生山地灾害研究的一些科学问题

汶川8.0级地震的发生远远超出地学界以前关于横断山区地震及次生灾害发生规律的认识,说明地学界以前对横断山区的新构造运动特点,地震区域分布规律、发生原因,地震次生滑坡泥石流灾害的强度、危害和特大地震在横断山区地貌演化的作用等重大科学问题的认识存在不足或偏差之处.在思考此次地震发生特点的基础上,结合在西南山区的多年工作经验,提出了汶川大地震后亟待开展的第四纪以来横断山区古地震重建、古滑坡分布、水库诱发地震、特大地震在横断山区山地地貌演化的作用等方面的科学研究问题.     

基于国际比较的中国原材料工业发展诊断

新世纪以来中国进入新一轮的重化工业加速发展期,原材料工业得以快速发展。“十二五”是中国从工业化中期向工业化后期转变的过渡时期,原材料工业将进入新的发展阶段。通过原材料工业发展的国际比较,发现中国原材料工业在规模、结构、布局、竞争力等方面存在的差距和面临的问题。随着工业化的阶段性转变,借鉴国际原材料工业的发展经验,结合新时期的新挑战,中国原材料工业将进入由规模扩张转向结构调整和升级以及注重增长方式发展的转变时期。