尾波的场地放大作用及其在S波场地响应中的有效应用

本文的主题是，研究是否可由尾波测得特定场地的Ｓ波响应。我们使用了南加州４个ＴＥＲＲＡ地学透镜台观测到的１９９２年半德期和大熊地震的余震的记录。由于ＴＥＲＲＡ地学透仪的大动态范围，所记录的Ｓ波具有宽频带响应，而尾波的持续时间也长。     

BED SHEAR IN EVOLVING SCOUR AT A CYLINDER:A THEORETICAL APPROACH

ＢＥＤＳＨＥＡＲＩＮＥＶＯＬＶＩＮＧＳＣＯＵＲＡＴＡＣＹＬＩＮＤＥＲ：ＡＴＨＥＯＲＥＴＩＣＡＬＡＰＰＲＯＡＣＨＳｕｂｈａｓｉｓｈＤＥＹ１ａｎｄＳｒｉｊｉｂＫ．ＫＡＲ２Ａｂｓｔｒａｃｔ：Ｔｈｅｔｅｍｐｏｒａｌｖａｒｉａｔｉｏｎｏｆｓｈｅａｒｓｔｒｅｓｓ...     

由富尔奈斯火山上的GEOSCOPE VBB台站得到的地倾斜信号

报道了距富尔奈斯火山顶8 km处的GEOSCOPE台网甚宽频带地震台观测到的甚长周期的瞬变过程。我们将地震台观测到的地面速度转换成地倾斜并通过与同一拱顶观测室内Blum型传统摆式倾斜仪记录的数据相比较检验了结果。通过比较表明,用水平地震仪测量周期小于25h的地倾斜是有效的。把这种方法用于1991年以来的几次火山喷发和岩浆侵入之前观测到的瞬变过程。由于GEOSCOPE台站到火山顶的距离适中,因而所得到的地傾斜观测值提供了有关火山喷发和岩浆侵入的信息,补充了火山顶部地倾斜观测网提供的有关岩浆源的形态和位置信息。     

结构非弹性动力响应的力模拟法

提出了基于力模拟法研究受动力荷载作用的结构非线性特性的一种新的算法，与传统改变刚度矩阵的方法不同，该算法是通过改变结构位移场来进行非弹性分析。结构的每一个非弹性变形代表一个自由度，因而结构所有的非弹性特性可通过一个方程表示。这个算法在计算时间上是非常有效的，因为它仅需使用初始刚度矩阵，且当运动动力分析中的状态空间数值积分法时，可以达到很高的数值精度。而且，这个算法在分析结构应变硬化性质、弹塑性性质和应变软化性质时都是稳定的。通过将这种算法与已有的非弹性动力分析软件程序相比较，说明了这个算法是的、高效的。最后，通过对一个6层医院建筑动力响应分析的应用，演示了该算法在分析实际结构中的完整的非弹性分析过程。     

Transboundary impacts on regional ground water modeling in Texas

Recent legislation required regional grassroots water resources planning across the entire state of Texas. The Texas Water Development Board (TWDB), the state's primary water resource planning agency, divided the state into 16 planning regions. Each planning group developed plans to manage both ground water and surface water sources and to meet future demands of various combinations of domestic, agricultural, municipal, and industrial water consumers. This presentation describes the challenges in developing a ground water model for the Llano Estacado Regional Water Planning Group (LERWPG), whose region includes 21 counties in the Southern High Plains of Texas. While surface water is supplied to several cities in this region, the vast majority of the regional water use comes from the High Plains aquifer system, often locally referred to as the Ogallala Aquifer. Over 95% of the ground water demand is for irrigated agriculture. The LERWPG had to predict the impact of future TWDB-projected water demands, as provided by the TWDB, on the aquifer for the period 2000 to 2050. If detrimental impacts were noted, alternative management strategies must be proposed. While much effort was spent on evaluating the current status of the ground water reserves, an appropriate numerical model of the aquifer system was necessary to demonstrate future impacts of the predicted withdrawals as well as the effects of the alternative strategies. The modeling effort was completed in the summer of 2000. This presentation concentrates on the political, scientific, and nontechnical issues in this planning process that complicated the modeling effort. Uncertainties in data, most significantly in distribution and intensity of recharge and withdrawals, significantly impacted the calibration and predictive modeling efforts. Four predictive scenarios, including baseline projections, recurrence of the drought of record, precipitation enhancement, and reduced irrigation demand, were simulated to identify counties at risk of low final ground water storage volume or low levels of satisfied demand by 2050.     

Bioaccumulation of nitroarenes in bivalves at Osaka Bay, Japan

This paper reports for the first time the detection and occurrence of nitroarenes (NPAHs) in marine organisms. Mussels and oysters collected from Osaka Bay, Japan, had total NPAHs concentrations that ranged from 2380 to 24,688 pg/g dry and 2672 to 25,961 pg/g dry, respectively. Relatively higher concentrations were detected in sampling sites located near the central district and suburbs of Osaka City implying that the most probable sources of NPAHs in the two bivalves are exhaust gases and smokes emitted by automobiles and industrial plants. Bivalves had relatively higher residues of 1-nitronaphthalene, 2-nitronaphthalene, 3-nitrophenanthrene, and 9-nitrophenanthrenes. Residues of 2-nitrofluorene, 1-nitropyrene, 4-nitropyrenes, and 6-nitrochrysene were much lower compared to nitronaphthalenes and nitrophenanthrenes. Inter-species differences was only observed for 2-nitronaphthalene with oysters exhibiting significantly higher residues than mussels.     

滑坡编目:地震滑坡危险性分析中必不可少的部分

详细精确的滑坡编目是地震滑坡危险性分析工作中必不可少的一部分。理想的编目要满足如下条件:覆盖整个地震影响区;应包含所有可调查到的滑坡,滑坡的最小长度应小至1～5m左右;编目中的滑坡位置也必须准确,应使用能够反应它们真实的平面形状的区要素来表征。符合上述要求的滑坡编目可以用来进行地震滑坡危险性分析和其他的定量分析研究。详细的地震滑坡编目可以追溯到1960年代初的航空摄影技术的出现与应用。近年来,随着空间技术科学的进步,高分辨率卫星影像获取成为可能,从而使得除最小的滑坡之外可以识别并绘出所有由地震事件触发的滑坡。得益于遥感技术的这种可以观测到地球任何地方的能力,我们可以获取到任何大量地震滑坡发生区域的遥感影像。然而,随着高分辨率遥感影像时代的到来,地震滑坡编目数据不完整也成为当前研究中的一个普遍存在的问题。     

2009年日本骏河湾地震后东海俯冲带上应力转移之探讨

日本西南部位于菲律宾海俯冲板块和欧亚上冲板块交界处。1944年和1946年,东南海和南海分别发生一次8级大逆冲型地震,但与该板块边界相邻的东海却仍保持闭锁状态[1]。因此,东海地区有可能会发生一次大逆冲型地震。2009年,骏河湾发生6.4级地震,地震位于菲律宾海俯冲板块内,靠近东海地区。在此,我们利用断层滑动模型来研究由骏河湾地震引起的应力变化[2]对东海地区的影响。我们发现在这次地震之后,板块边界的地震活动发生率有所上升。东海地区推测的强闭锁地段大都位于应力逐渐增大的地区。其中一小块闭锁地段的破裂——发生在地震应力达到临界值之后——就会引起整个东海地区的破裂,最终引发一场大逆冲型地震。