FUZZY PATTERN CLASSIFICATION OF STRONG GROUND MOTION RECORDS

Classification of earthquake strong ground motion (SGM) records is performed using fuzzy pattern recognition to exploit knowledge in the data that is utilised in a genetic algorithm (GA) search and scaling program. SGM records are historically treated as “fingerprints” of certain event magnitude and mechanism of faulting systems recorded at different distances on different soil types. Therefore, databases of SGM records of today present data of complex nature in high dimensions (many of the dimensions—or SGM parameters in time and frequency domain—are presently available from different archives). In this study, simple ground motion parameters were used but were combined and scaled nonlinearly such that the physical properties of the data could be preserved while reducing its dimensionality. The processed data was then analysed using fuzzy c-means (FCM) clustering method to explore the possibility of meaningfully representing earthquake SGM data in lower dimensions through finding subsets of mathematically similar vectors in a benchmark database. This representation can be used in practical applications and has a direct influence on the processes of synthesising ground motion records, identifying unknown ground motion parameters (e.g. soil type in this study), improving the quality of matching SGM records to design target spectra, and in rule generalisation for response. The results showed that the stochastic behaviour of earthquake ground motion records can be accurately simplified by having only a few of motion parameters. The very same parameters may also be utilised to derive unknown characteristics of the motion when the classification task on “training” records is performed carefully. The clusters are valid and stable in time and frequency domain and are meaningful even with respect to seismological features that were not included in the classification task.     

SITE AMPLIFICATION FACTOR IN ANCHORAGE,ALASKA BASED ON LONG PERIOD MICROTREMORS

Long period microtremors with periods ranging from 0.5 to 10 seconds were measured in the Anchorage metropolitan area. Two horizontal components of motion were recorded at 81 sites uniformly distributed throughout the basin with spatial resolution of about 2 km. Recording at each site was done for 300 seconds with a sampling rate of 20 Hz. Repeated measurements were performed at a bedrock reference site simultaneously with the measurements in the field. The measurements were completed in six days. In addition, multiple recordings were obtained concurrently at the reference bedrock site and a sediment site. Based on these measurements the Fourier spectra were calculated for each of the site. Ground motion amplification is determined in terms of spectral ratio of horizontal spectral amplitudes at a sediment site and the reference bedrock site. Mean spectral ratio contours were evaluated for different period bands. The results show that for period band 3 to 5 seconds the spectral ratio contours agree well with the ground failure susceptiblity map of Anchorage.     

Interpretation of elevation-scan HF backscatter data from Losquet Island radar

Most methods using HF ground backscatter radar data to estimate the ionospheric bottomside electron density profile rely upon multi-frequency measurements of the minimum group delay. However, information of the same nature can also be extracted at a single frequency if the elevation angle can be precisely controlled. We outline the analysis of this technique, known as elevation-scan backscatter sounding. The relevant parameter estimation problem is studied using a Bayesian approach. We report on an experiment using the Losquet Island radar to illustrate this method. The performance is compared to ionosonde data. This technique provides a method of teledetection of the bottomside F-region electron density profile hundreds of km from the radar site: however, further development is needed to provide increased reliability of the estimates.     

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.     

SEISMIC DESIGN REGULATION CODES: CONTRIBUTION OF K-NET DATA TO SITE EFFECT EVALUATION

The purpose of this study is to compare the site effect section of building codes (EC8 and UBC97) with the set of data provided by the Kyoshin network. In order to obtain a set of site coefficients and spectral shapes, we have first deduced an attenuation law for both horizontal and vertical motion. Site conditions are represented by the shear velocity averaged over the upper 30 m (V _s ³⁰). Our site classification (4 categories similar to those proposed in the new ECS and the UBC97) is based on borehole investigations at every station. This classification has permitted to distinguish clearly four response spectra which demonstrates the efficiency of V _s ³⁰ as characterising site conditions. Our law is then used to test site coefficients and spectral shapes of building codes ECS and UBC97. Concerning spectral shapes and site coefficients, our results are found to be in good agreement with EC8 and UBC97 only if category B (400<V _s ³⁰<800 m/s) is taken as reference. We also conclude that a site which is characterised as “rock” on geological criteria can not generally be classified in category A (V _s ³⁰>800 m/s). This suggests that classification in category A should be based only on field measurements. Concerning vertical motion, our analysis of the K-NET data shows that the ratio av/ah (vertical peak ground acceleration over horizontal peak ground acceleration) is between 0.50 and 0.68.     

Determining the settlement history of Hellenistic,Roman, and Byzantine sites in the Galilee,Israel: Comparing surface,subsurface, and stratified artifact assemblages

Abstract

Archaeological field survey is the basic method for determining the history of settlement on the regional level. The backbone of survey is locating and surveying individual sites, estimating their size, and uncovering their settlement histories. Various biases place doubt on the reliability of surface data and the conclusions drawn from them. This study presents three methods for investigating multiperiod sites in eastern Galilee, Israel: advanced surface survey, shovel test sampling, and large-scale stratigraphic excavations. Advanced surface survey was carried out at 46 sites settled during the Hellenistic through Byzantine periods (ca. 300 b.c.–a.d. 650). Three of these sites were later sampled using shovel test pits. Large-scale excavations were conducted at two of these sites, Khirbet Wadi ?amam and Nasr ed-Din enabling the comparison of the three methods. Applying these three methods to the same sites allowed us to evaluate the advantages and disadvantages of each method for determining settlement history. The results indicate that a thorough surface survey of a site in an area where local pottery is well documented can provide a clear picture of its occupation history. However, these data are not sufficient to determine variations in the size of the site over time. Shovel test sampling presents no advantage over surface survey with regard to documenting periods of activity at a given site, but it is preferable for tracing changes in the intensity of occupation during different periods. Excavation is the most informative method, but because it is costly and time consuming, it often sheds light only on small portions of selected sites.     

Improving Distance Estimates between Areal Units in Migration Models

There are many methods of modeling migrant flows within a set of areal units, but it is common in most to incorporate some measure of distance as an explanatory variable. These distances are effectively meant to represent the typical distance between pairs of areas that would be traveled by potential migrants. They are usually calculated between population-weighted centroids derived for each zone. It is argued here that this method of calculating distance is biased and that the zonal system used will influence the final model parameters that are intended to describe the underlying migration process. The distances between nearby zones will be particularly poorly specified using this approach, but other problems arise which relate to the shape of the zones and the position of the zones in relation to each other. This paper describes an alternative method of calculating these distances which reduces this bias. It is shown that the resulting models fit the data far more satisfactorily and that the residuals from models incorporating this approach are significantly different from those identified from models that use the standard method of specifying distance.     

A NON-PARAMETRIC APPROACH TO ATTENUATION RELATIONS

Abstract

A non-parametric multidimensional regression method is proposed for the prediction of seismic ground motion parameters. The main features which distinguish the method from standard regression procedures are: (1) The relationship between the input and output variables is not selected a priori by a prediction law, (2) an arbitrary number of input variables Can be taken into account, provided that an appropriate data base exists, and (3) the computational procedure is very simple. The results can be easily updated when new information becomes available. The method has been applied for the derivation of attenuation relations by using a combination of databases compiled by other researchers. In the majority of the cases discussed in this paper, the method was used for the prediction of horizontal peak ground acceleration as a function of magnitude and distance. In some cases, ground conditions were also taken into account. Some results on the attenuation relations of peak ground velocity and displacement, as well as Arias intensity, are also presented.     

Migration and implicit amenity markets: does incomplete compensation matter?

We first develop an empirical approach for generating measuresof wage over or under compensation (incomplete compensation)for location attributes. We then devise a method to test whethermigration is influenced by incomplete compensation in wagesfor location characteristics. An intercity wage regression isestimated where fixed effects capture the impact of site characteristicson wages. We then regress the fixed effects on a comprehensivevector of site attributes, where the residuals from this stagecapture incomplete compensation in wages. The derived measuresof incomplete compensation are included in a standard microdata-baseddiscrete choice model of migration. The results suggest thatincomplete wage compensation for site characteristics mattersin migration decisions, and the findings are consistent withtendencies toward spatial equilibrium in the distribution ofpopulation.     

A hierarchical taxonomic procedure for provenance determination: A case study of Chalcolithic ceramics from the central Zagros

This study develops a data analysis methodology for the exploration of the variance in chemical composition of ceramic artifacts due to their typological, location and temporal characteristics. This methodology then allows for the characterization of ceramics based on these characteristics and the sequential assignment of unclassified ceramics to a region, subregion or site, with further assignment to specific ware and chronological period. The procedure uses INNA data on the elemental composition of ceramics in order to derive a series of classification functions for each category within each level of the taxonomic hierarchy. The developed procedure is used to investigate a provenance problem involving Chalcolithic ceramics from the Zagros region of western Iran. The results show that the elemental composition of ceramics, when coupled with multivariate statistical techniques, represents a powerful means for distinguishing ceramic provenance.     

A GIS method for assessing the zone of human-environmental impact around archaeological sites: a test case from the Late Neolithic of Wadi Ziqlâb,Jordan

Assessing the impact of prehistoric sites on their local environment is difficult to accomplish with standard archaeological methods. Simulation modeling offers a solution to this issue, but it is first necessary to delimit a site catchment, or “zone of impact”, around archaeological sites in which to carry out human–environment interaction modeling. To that end, I have developed a new method for GIS-based catchment reconstruction and distilled it into a custom module (r.catchment) for GRASS GIS, which calculates catchments of a given area based on anisotropic travel costs from a point of origin. One method of applying this new module in exploratory catchment modeling is discussed using the pastoral economy of the Late Neolithic period in Wadi Ziqlâb, Northern Jordan as a test case. A model of Late Neolithic herding economy and ecology is constructed, which combines data from archaeology, phytogeography, range science, agronomy, and ethnohistory. Four sizes of pastoral catchments are then derived using r.catchment, and the herd ecology model is used to estimate the stocking-rate (carrying capacity) of mixed goat and sheep herds for each catchment. The human populations these herd numbers could support (between 3 and 630 people in the Wadi) are then compared with human population estimates derived from household architectural analyses (between 18 and 54 people in the Wadi) to determine the most probable catchment configurations. The results indicate that the most probable zone of impact around the known Late Neolithic sites in Wadi Ziqlâb was somewhere between 9 and 20 square kilometers, delineated by 3 and 4.5 km pasture radii respectively.     

3D modelling of magnetic data from an archaeological site in north-western Tlaxcala state,Mexico

In Archaeology, geophysical methods had been applied usually in a qualitative form, limited only to the use of filters that enhance the data display. The main objective in this work is the implementation of a modelling technique that allows us to reconstruct the geometry of buried bodies and the determination of their depths. This is done by means of the estimation of the magnetic moments of archaeological objects using a three-dimensional mesh of individual magnetic dipoles using the least squares method and the singular value decomposition of a weighted matrix to solve the linear problem. The distribution and shape of the underlying archaeological remains can be inferred. This methodology was applied to an archaeological site called Los Teteles de Ocotitla, in the state of Tlaxcala, Mexico. A high-resolution magnetic prospection was carried out in three selected areas (terraces). The most important total field anomalies found on each area were inverted, obtaining results that were corroborated by archaeological excavations. This investigation demonstrates the potential of quantitative geophysical methods for the characterization of archaeological structures, in extension and in depth.     

Development and Verification of a New Site Classification System and Site Coefficients for Regions of Shallow Bedrock in Korea

In this article, site response analyses for 124 sites collected in Korea were performed to evaluate earthquake ground motions in regions of shallow bedrock in Korea. Based on the results, a new two-parameter site classification system was developed for use in regions of shallow bedrock. The system incorporates depth to bedrock and mean V_S of soil above bedrock as parameters for site classification instead of V_S30. Soil sites were divided into seven site classes and the corresponding site coefficients were proposed for each site category. Some verification work demonstrates the superiority of the proposed system over the current seismic codes.     

A comparison of different non-destructive methods of age estimation in skeletal material

The skeletal remains of unidentifiable persons, recovered in recent years from the churchyard adjoining the House of Correction in Oslo, included 91 instances in which the maxillae and/or mandibles had been preserved, and these were examined. The length of the apical translucent zone in unsectioned teeth and the amount of secondary dentine deposit have been regarded as two of the most reliable factors in odontological age estimation. This study has used two methods, each using one of these factors, on single-rooted teeth from, respectively, 78 and 76 individuals. The distribution of age at death, as estimated from the two dental methods and from anthropological criteria, was then compared with the distribution of age at death of 380 individuals recorded in the church register for the House of Correction. Age calculations from secondary dentine, measured indirectly on dental radiographs of premolars, and estimates based on anthropological criteria both seemed to approximate to the chronological age distribution better than age estimates based on the length of the apical translucent zone. Statistical analyses indicated that all three methods of age estimation were significantly different (p<0.05). When compared with the church register, each method assigned a lower percentage of individuals to the younger and older age-groups and a higher percentage to those in the middle. No statistical difference could be found between the age distribution from the church register and estimates from either anthropological criteria or dental radiographs; but when age estimates based on these two latter methods were compared, 39.5 per cent differed by more than 10 years.     

A NOTE ON THE FORMULATION OF A FULL-ANALOGUE REGRESSION MODEL OF THE SHIFT-SHARE METHOD

ABSTRACT. This paper presents a full-analogue regression model of the deterministic shift-share method, for analyzing the components of regional employment change. The model is formulated as a constrained least squares regression problem. This leads to a direct determination of estimates for the national, industrial, and regional growth coefficients. The statistical significance of these coefficients and the overall model can then be tested by using standard regression test statistics.     

Artifact orientations and site formation processes from total station proveniences

It is well understood that the orientation of clasts within a deposit can yield information on site formation processes. Although the term clast usually refers to the natural component of a deposit, the artifactual and faunal components are also known to be sensitive to site formation processes. There are a number of ways in which orientations can be recorded and analyzed, and this paper describes how orientations can be recorded as part of piece proveniencing artifacts with a total station. After the method is described, the calculation, statistical analysis and presentation of artifact orientations are considered. The final part of the paper presents orientation data from Pech de l'Azé IV recorded and analyzed in this way. The example demonstrates the effectiveness of the total station method of recording orientations, their sensitivity to site formation processes, and the importance of using multiple methods of data analysis and presentation to assess and interpret patterning.     

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.     

Quantification of slag heap volumes and masses through the use of induced polarization: application to the Castel-Minier site

When used for archaeological purposes, geophysical methods are often useful for the exploration, detection and mapping of archaeological remains. In the case of ancient metallurgical activities, slag accumulations form precious mineral records of these activities. Evaluating the volume of slag produced in such locations is an important issue, since it enables an estimate of the amount of metal produced in the smeltery. Unfortunately, slags themselves cannot be easily detected by DC electrical methods. Although they can be easily detected using magnetic techniques, these methods do not allow for an estimate of the quantity of slag, because magnetic fields do not conserve magnetic flux. In the present study we show that the Induced Polarization method (IP) is suited to the quantification of buried slags, provided the slag response has been suitably calibrated prior to the field measurements. The ability to quantify the quantity of slag is based on the quasi-linear relationship between the main IP parameter, i.e., the chargeability, and the slag concentration. This approach provides a new, non-invasive tool for the estimation of the volume of buried slag in palaeometallurgical sites.In this paper, an application of this technique for the site of Castel-Minier, Ariège, France, is presented.     

Representing Structural Change in U.S. Migration Patterns

This paper focuses on the identification of three sets of relationships exhibited by a time series of age-specific national migration rates and multiregional transition probability matrices: the relationship across time for the same age group, as defined by period (temporal) transformation coefficients or matrices; the relationships across age at a particular moment in time, as defined by age transformation coefficients or matrices; and the relationships across time and age, as defined by cohort transformation coefficients or matrices. Given any two of these relationships one can solve for the third. This feature of age-period-cohort relationships has a practical application in the development of improved methods for representing structural change in migration patterns over time and for indirectly estimating migration patterns using inadequate data.     

Using measures of cost distance in the estimation of polity boundaries in the Postclassic Yautepec valley,Mexico

The reconstruction of polity boundaries is essential for the study of political evolution, but few enhancements to archaeological boundary estimation methods have been proposed in recent years. New techniques of terrain modeling and geographical analysis provide the means to augment traditional methods of boundary estimation. In this paper, I review archaeological methods for estimating the spatial location of boundaries between independent polities and ways to modify these methods to explore the processes of political expansion in the evolution of complex societies. I demonstrate several of these methods using data from Postclassic polities in the Yautepec valley, Morelos, Mexico. Through time, seven independent polities were founded, expanded, and were ultimately incorporated within two levels of regional political administration. I apply new quantitative methods for the estimation of polity territories and explore the processes that resulted in the formation of a regional polity. The resulting boundaries are objective estimates of the location of borders based on energetic efficiency that can be systematically tested against theoretical models. These estimated boundaries provide a basis for exploring the social meaning of territorial divisions. Additionally, energetic boundaries provide a means for delineating local zones for landscape utilization and comparative analyses.