Preliminary Discussion on the Implication of Determination of Source Depth of Earthquakes

In an earthquake catalog,the source depth of earthquakes is one of the most basic parameters; however it is also one of the most difficult to measure.The source depths in the PDE bulletin,the centroid depths from CMT inversion of USGS and Harvard University,and those obtained by depth phases of broadband waveform data are not equal to each other,and they are also have different meanings.Also,the depth obtained from broadband waveform modeling is another kind of depth of different a rupture "core." This paper preliminarily discusses the physical implication of the source depth of earthquakes with different measuring methods.     

张家口Ms4.2地震前的地下流体异常

１９９７年５月２５日张家口ＭＳ４．２地震是１９９７年上半年首都圈地区发生的显地震,虽然该地震震级不高,但地下流体的短临异常十分显。作主要介绍了该地震前地下水流体短临异常的特征高此得到的科学启示 。     

ODONATE COMMUNITIES （ODONATA： INSECTA） IN A TROPICAL RIVER BASIN, MALAYSIA

Odonata larvae were sampled from 16 tributaries of Kerian River in the Kerian River Basin (KRB) using a kick samphng technique from September 1998 to May 1999 encompassing both rainy and dry seasons. The distribution of odonate genera was significantly different ( F15.16 = 3.99) among rivers in both seasons ( F15.16 = 4.70) at P = 0.05. However, no seasonal influence was detected. Protoneuridae and Libellulidae were the most dominant families in this basin. Other families Gomphidae, Coenagrionidae, Macromiidae, Chlorocyphidae and Calopterygidae, were common but Aeshnidae and Eupheidae were rare. Several common species, Prodasineura autumnalis, Brachythemis contaminata, Macromia gerstaeckeri, Paragomphus, Orthetrum brunneum, Rhinocypha quadrimaculata and Copera marginipes were identified. The calculated values of biological indices ( H‘, D, E, R1 and R2) showed that the dragonfly fauna in this river basin was slightly poor. Varied physieo- chemical parameters of the river possibly as a result of human activities in surrounding areas were found to influence the distribution of the dragonfly larvae in the KRB. This study showed that the KRB provided favorable habitats for Protoneuridae and 1Libellulidae. Two most dominant species Prodasineura autumnalis and Brachythemis contaminata were obviously favoured slightly acidic water of the Kerian river tributaries.     

Plasticity‐fibre model for steel triangular plate energy dissipating devices

Properly fabricated triangular‐plate added damping and stiffness (TADAS) devices can sustain a large number of yield reversals without strength degradation, thereby dissipating a significant amount of earthquake‐induced energy. A pronounced isotropic‐hardening effect is recognized in the force‐deformation relationships of the TADAS devices made from two grades of low yield strength steel. The proposed plasticity‐fibre model employing two surfaces (a yield surface and a bounding surface) in plasticity theory accurately predicts the experimental responses of the TADAS devices. This model is also implemented into a computer program DRAIN2D+ to investigate a frame response with the TADAS devices. Substructure pseudo‐dynamic tests and analytical studies of a two‐storey steel frame constructed with the low yield strength steel, LYP‐100 or LYP‐235 grade, TADAS devices confirm that the dynamic structural response can only be predicted if the proposed plasticity‐fibre model is used for LYP‐100 steel TADAS device. Copyright © 2002 John Wiley & Sons, Ltd.     

关于发展我国地下流体前兆流动观测问题的建议

介绍了地下流体前兆流动观测及其目的与意义、国内外地下流体前兆流动观测的历史与现状、我国目前存在的主要问题；针对现状与问题，提出了建议我国地下流体前兆流动观测系统的建议，其中包括指导思想、发展目标、观测网的类型与布设、观测点的建议、观测项目与观测仪器的选择、观测工作的组织与实施、观测数据的产出与共享等科学与技术问题。     

关于地震地下水观测井建设的若干问题

根据有关的国家与地震行业技术标准,结合建井的实践经验,本文论述了地震地下水观测井的定位、观测井结构设计与钻井施工的技术要求。     

Steel buckling‐restrained braced frames with single and dual corner gusset connections: seismic tests and analyses

The design of a three‐story buckling‐restrained braced frame (BRBF) with a single‐diagonal sandwiched BRB and corner gusset was evaluated in cyclic tests of a one‐story, one‐bay BRBF subassembly and dynamic analyses of the frame subjected to earthquakes. The test focused on evaluating (1) the seismic performance of a sandwiched BRB installed in a frame, (2) the effects of free‐edge stiffeners and dual gusset configurations on the corner gusset behavior, (3) the frame and brace action forces in the corner gusset, and (4) the failure mode of the BRBF under the maximum considerable earthquake level. The subassembly frame performed well up to a drift of 2.5% with a maximum axial strain of 1.7% in the BRB. Without free‐edge stiffeners, the single corner gusset plate buckled at a significantly lower strength than that predicted by the specificationof American Institute of Steel Construction (2005). The buckling could be eliminated by using dual corner gusset plates similar in size to the single gusset plate. At low drifts, the frame action force on the corner gusset was of the same magnitude as the brace force. At high drifts, however, the frame action force significantly increased and caused weld fractures at column‐to‐gusset edges. Nonlinear time history analyses were performed on the three‐story BRBF to obtain seismic demands under both design and maximum considerable levels of earthquake loading. The analytical results confirmed that the BRB and corner gusset plate achieved peak drift under cyclic loading test. Copyright © 2011 John Wiley & Sons, Ltd.     

Relationship between oceanic heat content and sea surface height on interannual time scale

The relationship between heat content and sea surface height (SSH) in the global ocean on the interannual time scale is examined with satellite altimeter measurements, historical hydrography, and model assimilation outputs. Results show that correlation between altimetric SSH and heat content in the upper 700 m calculated from Ishii data is geographically nonuniform. In the tropical ocean, heat content and SSH are strongly correlated and exhibit nearly the same interannual variations. In the polar ocean, their correlation is relatively weak. Further analysis with Simple Ocean Data Assimilation outputs shows that such nonuniform distribution is not from dynamical origin but from the limited integral depth selected to calculate heat content. The integral depth of 700m is inadequate to capture variation of the deep main thermocline in the polar region. The halosteric effect also contributes to the nonuniform pattern of correlation, because saline contraction becomes significant in the polar ocean owing to low temperature.     

Seismic performance evaluation of a 34‐story steel building retrofitted with response modification elements

The original structural design of this case study consisted of five basement floors and a 34‐story hotel tower in Kaohsiung, Taiwan. The construction started in 1993, and the erection of the entire steel frame and the pouring of concrete slabs up to the 26th floor were completed before 1996. However, construction of the original hotel was subsequently suspended for 10 years. Recently, this building has been retrofitted for residential purposes. Buckling restrained braces (BRBs) and eccentrically braced frames were incorporated into the seismic design of the new residential tower. This paper presents the seismic resisting structural system, seismic design criteria, full‐scale test results of one BRB member and the as‐built welded moment connections. Test results confirm that the two side web‐plate stiffening details can effectively improve the rotational capacity of welded moment connection. The paper also discusses the analytical models for simulating the experimental responses of the BRB members and the welded moment connections. Nonlinear response history analyses (NLRHA) indicate that the inelastic deformational demands of the original and the redesigned structures induced by the maximum considered earthquakes are less than those found in the seismic building codes or laboratory tests. This paper also proposes a ground motion scaling method considering multi‐mode effects for NLRHA of the example building. It is shown that the proposed scaling method worked well in reducing the scatter in estimated peak seismic demands. Copyright © 2008 John Wiley & Sons, Ltd.