RELATION BETWEEN BUILDING DAMAGE AND GROUND CONDITIONS IN THE 1999 QUINDIO EARTHQUAKE IN COLOMBIA

An earthquake of magnitude 6.2 (M _b ) occurred in west-central part of Colombia on January 25, 1999. This earthquake is officially called Quindio Earthquake from the name of the most affected province. The earthquake caused disastrous damage to a large number of buildings resulting in significant casualties. In Armenia City and its neighbouring villages close to the epicentre over 1000 people were killed by the earthquake and the total monetary loss reached US$ 2 billion. Armenia City, which has an approximate population of 280 000 people, apparently suffered the worst in terms of casualties and damage to the buildings.

The present paper focuses on the causes of damage to houses and buildings in Armenia City. First, the evolution of the urban area of the city was investigated using historical features available maps from each era. Then a correlation between buildings damage and topographical features of the city was studied. The effects of geological features and amplification of ground motion were also investigated.     

NOTE ON THE INCLUSION OF SITE CLASSIFICATION INFORMATION IN EQUATIONS TO ESTIMATE STRONG GROUND MOTIONS

Two main regression methods have been proposed for using site category information within ground motion prediction equations, these are: (a) joint estimation of the site category coefficients and the magnitude and distance coefficients; or (b) estimation of site category coefficients by using the residuals from the equation derived without considering soil conditions. Method (a) requires each record be assigned a site category whereas for method (b), because it relies on residuals, site information can be missing for some records. This short note finds that if the mean of the transformed distances within each site category is the same then the two methods give the same site coefficients. If, however, these means are significantly different then method (b) can yield incorrect site coefficients.     

SEISMIC HAZARD IN GREECE BASED ON DIFFERENT STRONG GROUND MOTION PARAMETERS

The available Greek strong ground motion records to date are used in order to study the duration of strong-motion in Greece, covering magnitudes between 4.5 and 6.9 and distances from 1 km to 128 km. An attenuation relation of strong-motion duration is calculated and compared to earlier existing similar relations proposed for Greece and Japan. Furthermore, the seismic hazard for the area of Greece is assessed, using the strong-motion parameters of duration and peak ground acceleration. The results are presented in the form of a map according to which Greece is classified in four different categories of equal seismic hazard.     

THE EFFECTIVE DURATION OF EARTHQUAKE STRONG MOTION

The duration of strong ground shaking during earthquakes can play an important role in the response of foundation materials and structures, particularly when strength or stiffness degradation is encountered. A thorough seismic hazard assessment should therefore include an estimation of the expected duration of strong motion, which first requires criteria to define the part of an accelerogram considered to represent the duration of strong ground motion. Some 30 different definitions of strong motion duration are reviewed and classified into generic groups. Problems that arise with the use of these definitions for duration are highlighted. A new definition of duration is presented using a previously unexplored option which identifies the part of the record where the main energy is contained and constrains this strong shaking phase by absolute criteria. This new definition is shown to give consistently meaningful durations for strong earthquake accelerograms from an engineering viewpoint. The correlations between the new definition of duration and magnitude, soil conditions and distance are explored as a first step towards the development of predictive equations.     

PROCEDURE AND SPECTRA FOR ANALYSIS OF RC STRUCTURES SUBJECTED TO STRONG VERTICAL EARTHQUAKE LOADS

Abstract

In view of the compendium of field evidence and supporting analysis work indicating the possible damaging effects of vertical earthquake ground motion, this paper addresses the problem of code-type vertical force calculation. In light of recent engineering seismology studies of the relationship between vertical and horizontal peak ground acceleration, the inadequacy of the 2/3-rule depicted by codes is highlighted. A simple piece-wise linear relationship is proposed and shown to represent existing strong-motion measurements adequately. Bilinear and inelastic spectra are derived and studied. It is demonstrated that net tensile forces and displacements may ensue, thus eroding the shear resistance of RC columns. A simple procedure is outlined whereby modal analysis may be employed to estimate conservatively vertical earthquake forces on buildings. Finally, areas of further exploration and refinement are identified.     

EMPIRICAL EVALUATION OF SITE EFFECTS BY MEANS OF H/V SPECTRAL RATIOS AT THE LOCATIONS OF STRONG MOTION ACCELEROMETERS IN ISRAEL

Acceleration data from local and regional earthquakes is of prime importance in evaluating the seismic hazard. Consequently, strong motion accelerometers are currently installed at more than 60 locations in Israel. We have explored the possibility of site amplification effects at 10 sites where local earthquakes triggered strong motion accelerometers by integrating empirical and analytical estimations. Implementing H/V spectral ratio techniques using 15 accelerograms from nine earthquakes, 105 seismograms shear-wave records of 35 local and regional earthquakes and seismograms of microtremors were used in the empirical evaluations. The subsurface models were constructed by integrating available geological and geophysical information at the analysed site with empirically evaluated site response functions. Amplification effects of factor 3-6 are observed at various frequencies in the 0.8-6.0 Hz band. Through the analysis process it became evident that the instant availability of many useful time windows of microtremors provides systematic estimations of the fundamental resonance frequency of each site and their associated amplification levels, which are similar to those obtained from H/V spectral ratios of seismograms and accelerograms and to those inferred from the subsurface geology. Analytical transfer functions should be reviewed with respect to empirical site response evaluations. Estimations that are based on only one approach may be totally misleading.     

VERTICAL EARTHQUAKE GROUND MOTION RECORDS: AN OVERVIEW

Recent research clearly shows the importance of including the vertical component of earthquake ground motion in seismic analysis and design. In addition, pioneering studies [e.g., Elnashai and Papazoglou (1997)] have explored and documented the characteristics of available near-field vertical ground motion records. As a follow-up, this paper complements earlier studies, and investigates additional far-field records and available downhole array vertical motion records. A total of 111 free-field strong motion records (from California) and available downhole array records are employed. Compared to near-field records, far-field records generally contain more energy at longer periods. Based on the available data, response spectra are presented for near-field and far-field records respectively. The currently scarce downhole-array vertical motion records show that significant amplification may occur within the top 10-20 m soil layers. A simple one-dimensional (ID) vertical wave propagation model did not appear adequate for modelling the observed downhole array response. In using such a simplified model, very high viscous damping in the range of 15-25% was needed to match the recorded downhole vertical response, even for small tremors. Additional data and research are required [Beresnev et al., 2002] towards the development of a rational vertical motion site response analysis procedure.     

ESTIMATION OF NEAR-SOURCE GROUND MOTION AND SEISMIC BEHAVIOUR OF RC FRAMED STRUCTURES DAMAGED BY THE 1999 ATHENS EARTHQUAKE

On September 7, 1999 an earthquake with magnitude M _W =5.9 occurred close to the city of Athens in Greece. More than 80 buildings collapsed, about 150 deaths and hundreds of injuries were reported. Soon after the event a damage investigation was carried out by two of the authors in the most heavily struck areas. The most serious damages were observed in the northern suburbs of Athens, where reinforced concrete frames and masonry buildings represent the prevalent construction systems. The hysteretic energy demands imposed on RC buildings should have been rather severe considering the structural systems characteristics and the inadequate construction details. However, over-strengths, redundancy and especially the presence of infill walls, provided a significant increase of the seismic capacity and contributed to the survival of many buildings.

The objective of the present work is to reproduce and analyse the response of typical RC frames subjected to the 1999 Athens earthquake in areas where the observed damage was particularly severe but no recordings of the ground motion were available. After a general overview of the seismotectonic environment, seismological data, observed macro-seismic intensities, structural typologies and observed building behaviour, an attempt is made to identify representative excitations in the meizoseismal area. Specifically, the required accelerograms are obtained by modifying available records so as to reproduce a given global energy content and to be consistent with the observed damage. To study the seismic response of RC models, the obtained accelerograms are used to perform nonlinear dynamic analyses.     

EFFECTS OF SOIL LAYERING ON THE CHARACTERISTICS OF BASIN-EDGE INDUCED SURFACE WAVES AND DIFFERENTIAL GROUND MOTION

This paper studies the effects of soil layering in the basin based on the characteristics of basin-edge induced surface waves and associated differential ground motion. Seismic responses of various basin-edge models were simulated using software based on parsimonious finite difference staggered grid approximation of 2.5D eiastodynamic wave equation. Seismic responses of various models with different number of soil/soft rock layers but for a fixed thickness of deposit, fundamental frequency and impedance contrast revealed a decrease of surface wave amplitude with an increase in the number of layers in the basin. Shifting of dominant frequency towards the higher values was obtained with an increase of number of layers. An increase of dispersion of surface waves with an increase of number of soil layers in the basin was observed. A minor increase of Rayleigh wave velocity with an increase of number of soil layers was also obtained, but in the case of Love wave it was almost negligible.

Spectral analysis of the edge-induced surface waves revealed that the anomalous earthquake intensity may arise in a zone of width of 2.5–3.0 km, parallel to basin-edge and at an offset of 0.5–0.7 km from the edge. Maximum horizontal differential ground motion (HDGM) developed by Love wave (≈4.9×10^?2) was more than that of Rayleigh wave (≈9.4×10^?3). Large variation in HDGM caused by the surface waves was obtained with a change in the number of layers in the basin and maximum HDGM was observed when there were only two layers in the basin. It was inferred that the effect of soil layering in the basin was more on the Rayleigh wave as compared to the Love wave. Development of large HDGM near the basin-edge and its dependency on the number of soil layers reveals that basin-edge induced surface waves need special attention during seismic microzonation or seismic hazard prediction.     

SHIFTING SETTLEMENT PATTERNS IN THE SOUTHERN JORDAN VALLEY AND DESERT FRINGES OF SAMARIA DURING THE EARLY BRONZE AGE I PERIOD

Abstract

This study deals with the unprecedented settlement activity during the Early Bronze Age I that has been recently recorded in the Jordan Valley and the desert fringes of Samaria. The increase in the number of sites primarily characterises the latter part of the period (Early Bronze Age IB), and is accompanied by two other important phenomena: population inroads into new regions, and the first appearance of fortified sites. A profound crisis at the end of the period resulted in the almost complete abandonment of the valley sites and the concentration of settlement along the eastern foothills of Samaria.     

SIGNIFICANT GROUND MOTION PARAMETERS FOR EVALUATION OF THE SEISMIC PERFORMANCE OF SLENDER MASONRY TOWERS

The evaluation of seismic risk of masonry monuments requires to study the combination of vulnerability and hazard. In the present work, the global seismic response of slender masonry towers has been studied by means of a specific 3-D fibre model. Accounting for the particular behaviour of such structures, the hazard should also be described by a suitable measure of intensity of the seismic action. A variety of different parameters relating with the ground acceleration recordings have been investigated for what regards their correlation with the damage indicators of the model. The combination of the peak ground velocity of the horizontal component and of the significant duration is an effective measure of intensity. This measure can be improved by considering the accord of the frequency content of the ground motion with the dynamical characteristics of the tower. Since in some cases the effect of the vertical component proved to be important, a further improvement can be obtained by taking into account also the vertical ground motion intensity.     

FROM THE FIRM GROUND OF RESULT AND FACT TO THE TOSSING SEA OF CAUSE AND THEORY: THE ROLE OF GOVERNMENT IN URBAN DEVELOPMENT*

Are government policies of any real significance in shaping the pattern of development in metropolitan regions? This essay summarizes the widely-held view that ‘economic forces’ determine the distribution of jobs and residences in urban areas, and argues that this conclusion involves serious conceptual difficulties. The essay then shows how the theory of political influence and related concepts can be used to clarify the issue of causation in urban development, and summarizes the authors' own substantive conclusions—that under certain specifiable conditions government activities do have a highly significant role in shaping metropolitan growth.     

PROVENANCING OF LIGHTWEIGHT VOLCANIC STONES USED IN ANCIENT ROMAN CONCRETE VAULTING: EVIDENCE FROM TURKEY AND TUNISIA

The mastery of the use of lightweight rocks in concrete as a means of controlling the thrusts of large‐scale vaults was among the most important contributions of the Roman builders to the development of vaulted architecture. The string of volcanoes along the Tyrrhenian coast of Italy produced a variety of lightweight rocks, which allowed the builders in Rome to develop highly sophisticated ways of manipulating form and mass to create stable structures. The use of lighter rocks in vaults and heavier in foundations occurs from the mid‐first century bc in Rome, but the systematic use of imported lightweight rocks only began in the early second century ad under Trajan ( Lancaster 2005 , 59–64). Soon thereafter, the technique of using lightweight stones to build large vaults spread throughout the empire, usually to areas that had a local source of lightweight volcanic material. However, there was also a seaborne trade in lightweight rocks to areas that did not have local sources of such material. The intention of our analysis is to determine as precisely as possible the provenance of the lightweight stones used in vaulting of two areas of the Mediterranean, modern Turkey (ancient Cilicia) and Tunisia (ancient Africa Proconsularis), and thus to provide a better understanding of the nature of this trade.     

AN EVALUATION OF ANALYTICAL AND INTERPRETATIVE METHODOLOGIES FOR THE EXTRACTION AND IDENTIFICATION OF LIPIDS ASSOCIATED WITH POTTERY SHERDS FROM THE SITE OF SAGALASSOS,TURKEY*

Three lipid analysis methods were applied to extracts of archaeological potsherds from the ancient city of Sagalassos, south‐west Turkey. In the fatty acid methyl ester fraction, obtained by selective transesterification of acylglycerols, the ratio of methyl palmitate to methyl stearate was determined. Secondly, by means of gas chromatography– combustion–isotope ratio mass spectrometry (GC–C–IRMS), stable carbon isotope ratios were measured for the same methyl esters. Finally, triglyceride composition was determined via high‐performance liquid chromatography–mass spectrometry (HPLC–MS). All three methods can be used to trace the origin of animal fat. Agreement between them is reasonable, especially in recognizing ruminant adipose fat. One sample was found to be of dairy origin using both GC–C–IRMS and HPLC–MS. The advantages of the various methods are discussed. Variations in lipid composition were observed between samples from different periods and excavated in diverse areas within the city of Sagalassos.     

COUPLED P-Y T-Z ANALYSIS OF SINGLE PILES IN COHESIONLESS SOIL UNDER VERTICAL AND/OR HORIZONTAL GROUND MOTION

Various approaches are currently used for the analysis of piles under vertical and lateral loading. Among these, the beam-on-a-nonlinear Winkler foundation (BNWF) approach using published P-y, T-z and Q-z curves is widely used in practice. In this approach, the P-y and T-z responses are generally uncoupled from each other. The objective of this paper is to investigate the influence that the coupling of the P-y and T-z responses has.on the cyclic and dynamic response of piles in cohesionless soil. A cyclic model is first developed and a parametric study is conducted to investigate the effect the initial confining pressure, angle of wall friction and effective vertical stiffness have on the lateral cyclic hysteretic response. A dynamic model is then developed, and used to study the response of a single pile in cohesionless soil under horizontal and/or vertical ground motion. Results from the parametric study showed that the three parameters did not have a significant influence on the lateral cyclic hysteretic response. Under horizontal and/or vertical ground motion, the horizontal ground motion was observed to dominate the inertial interaction response, and significantly affected both the horizontal and vertical displacement response, mainly due to second-order P-Δ and gapping effects.     

辽西地区新石器-青铜时代耕作业的兴衰与环境变化的关系

本通过分析辽西地区新石器时代至青铜时代考古化特征和耕作业的兴衰与环境变化的关系,揭示了该地区新石器时期以来化发展受耕作业的兴衰影响出现了多次倒退的现象。并认为环境条件特别是气候条件是影响辽西地区早期化发展的本质因素。气候温暖期,定居的农业化昌盛;气候寒冷期,农业经济解体,只能维持低水平的简单畜牧经济。造成新石器时代-青铜时代本区耕作业衰落和化倒退的直接原因是5000aB．P．-4000aB．P．降温事件及铁器冷期寒冷气候的作用。环境因素的剧烈波动过程,阻碍了本区化与生产经济形态的正常演进与发展。     

NATIONAL IDENTITY IN THE VANQUISHED STATE: GERMAN AND JAPANESE POSTWAR HISTORIOGRAPHY FROM A TRANSNATIONAL PERSPECTIVE

The defeat of Germany and Japan in 1945 required historians in both countries to reevaluate the past to make sense of national catastrophe. Sebastian Conrad's The Quest for the Lost Nation analyzes this process comparatively in the context of allied military occupation and the Cold War to reveal how historians in both countries coped with a discredited national history and gradually salvaged a national identity. He pays special attention to the role of social, discursive, and transnational contexts that shaped this process to highlight the different courses that the politics of the past took in postwar Germany and Japan. The picture that emerges of German and Japanese historiography and the respective attempts to come to terms with the past is at odds with the conventional narrative that usually praises West German historians and society for having come to terms with their dark past, as opposed to postwar Japan, which is usually regarded as having fallen short by comparison. There was in fact far more critical historiographical engagement with the past in Japan than in West Germany in the 1950s. Reasons for the divergent evolution of the politics of the past in Germany and Japan should not be sought in the peculiarities of postwar national history but rather in an entangled transnational context of defeat, occupation, and the Cold War, whose effects played out differently in each country. These conclusions and others reveal some of the opportunities and special challenges of comparative transnational history.     

OXYGEN AND CARBON ISOTOPE ANALYSIS OF HUMAN TOOTH ENAMEL FROM THE NEW KINGDOM SITE OF TOMBOS IN NUBIA

This study examines the feasibility of using oxygen isotope analysis of tooth carbonate to identify immigrants from the New Kingdom site of Tombos in Nubia (n = 30). In comparison with published data, the results (δ¹⁸O_ca,VSMOW = 31.4‰) imply a substantial presence of immigrants. However, further analysis of these data strongly suggests the need to consider hydrological and cultural factors such as the contribution of aquifer waters to the Nile, use of groundwater sources, and differences in handling and storage of water. The carbon isotope analysis, in conjunction with published ⁸⁷Sr/⁸⁶Sr data, provides additional support for the presence of immigrants at Tombos.     

FROM RAW IRON TO SEMI‐PRODUCT: QUALITY AND CIRCULATION OF MATERIALS DURING THE IRON AGE IN FRANCE*

Iron raw materials provide a privileged source of information for the reconstruction of metallurgical techniques and the circulation of iron products. An interdisciplinary approach, combining archaeological and archaeometrical studies of the exemplars known from the French Iron Age, has been undertaken. This enables a new typological classification to be produced that demonstrates a correlation between morphological and structural properties. Through comparison with chronological data, it is possible to propose a reconstruction of the organization of production according to three main periods, which are characterized by the circulation of different qualities of iron and by diverse levels of artisanal specialization.