Predicting Probabilistic-Based Strong Ground Motion Time Series for Citadel of Arg-E-Bam (South-East of Iran)

The main objective of this article is to present a probabilistic-based strong motion compatible with the source-path and site soil condition given the probability of exceedence for citadel of Arg-e-Bam site bed rock (South-East of Iran). A Fourier amplitude spectral attenuation relation for bed rock beneath the site is proposed which permits the estimation of time-histories through a probabilistic seismic hazard analysis procedure. Due to lack of data, the two well-known simulation techniques, point source and finite fault models have been used for generating hundreds of strong motion as input data. Tens of model parameter values such as stress-drop nucleation points were used, in each specified magnitude-distance, to reduce the uncertainty effects inherently existing in seismological/geological parameters. The proposed attenuation relation is validated by comparing the estimated strong motion, in the form of Fourier amplitude spectral, using the proposed attenuation relation with those of recorded ground motion data at three stations far away from the assumed source so that the results would not be influenced by the near source problems such as directivity and fling step. The results of proposed technique is assessed by comparing the estimated response spectra, with 10% probability of exceedence and 5% damping ratio, with those of traditional uniform hazard spectra. The proposed technique is supposed to be used in retrofitting procedure of international historical adobe structures in Arg-e-Bam site, which have been damaged during the destructive Bam earthquake 2003, Iran     

GENERATION OF SYNTHETIC EARTHQUAKE ACCELEROGRAMS USING SEISMOLOGICAL MODELLING: A REVIEW

A stochastically based seismological model is described in this paper and used to generate synthetic accelerograms that are considered representative of intraplate earthquake events recorded on rock. The model, whilst well publicised in the seismological literature, is discussed and reviewed in this paper from an engineering perspective. The key factors influencing the frequency properties of the Fourier spectrum of the earthquake ground motion are presented and the differences observed between regions such as between eastern and western USA axe discussed. A procedure to generate representative artificial accelerograms from the Fourier spectrum is described. Average response spectra derived from these synthetic accelerograms are then compared with a selection of response spectra derived from recorded accelerograms to test and substantiate the model. The application of the seismological modelling approach to regions outside North America and the implications of the Displacement Based prinicples on the future development of seismological modelling have been addressed and discussed in the paper.     

Seleucia Pieria: an ancient harbour submitted to two successive uplifts

Historical sources ascribe the foundation of Seleucia (Seleukeia) Pieria to Seleucos I Nikator, shortly before the foundation of Antioch in the late 4th century BC. The Seleucia Pieria site seems however to have been inhabited earlier, perhaps from around 700 BC, possibly by a Greek population under an Assyrian ruler. The city became of considerable military importance during the wars between the Ptolemies and the Seleucids; it was occupied by the Romans in the 1st century BC, but had practically disappeared in the 6th century AD.
Geomorphological surveys in the area have revealed the existence of elevated marine notches and rims bioconstructed by vermetids, oysters and calcareous algae, which occasionally erode or intersect the archaeological sites, showing that two rapid land uplift movements, probably of seismic origin, took place during the late Holocene. The first movement, which occurred about 2500 ± 100 years bp, was the strongest one and caused a local vertical displacement of about 1.7 m, which may have severely affected the earlier Greek settlement. Though several earthquakes are reported to have occurred in the area during the following ten centuries, none of them seem to have been strong enough to cause significant vertical displacements. The second movement occurred around 1400 years bp, probably in May 526 AD, when a great earthquake followed by tsunami waves is known to have caused devastating damage in Antioch and Seleucia. According to geomorphological data supported by several radiocarbon dates, the earthquake was accompanied by a 0.7 to 0 8 m upheaval. This seismotectonic event also caused a rapid silting of the Seleucia Pieria closed harbour basin and entrances, thus preventing its further use.     

A LOGIC TREE EXTENSION OF THE CAPACITY SPECTRUM METHOD DEVELOPED TO ESTIMATE SEISMIC RISK IN OSLO,NORWAY

The city of Oslo, Norway, was affected by a magnitude 5.4 earthquake in 1904 causing widespread minor damage. The earthquake occurred around 100 km south of Oslo within the Permean rift structure that runs North-South along the Oslofjord, and deep clay deposits under the city contributed to the damages. A seismic risk scenario including soil amplification and buildings classifications has been conducted with two earthquake sources, one very close to the city and one near the 1904 epicenter. Both scenarios exhibit strong dependencies on the soft clays underlying large parts of Oslo. The results confirm the 1904 effects, but also show a strong dependency on the applied attenuation functions. All computations are based on the capacity-spectrum method, and the predefined pushover curves and vulnerability functions were adopted from the HAZUS code. With this basis, the computational scheme was developed independent from the GIS framework, and a weighted logic tree formulation was implemented for appropriate treatment of epistemic uncertainties.     

南京长江大桥桥头堡抗震加固受力性能研究

为研究南京长江大桥桥头堡填充墙加固对结构抗震性能的影响,提出考虑较高填充墙开裂的双斜撑模型,用于罕遇地震工况下桥头堡的抗震性能计算,同时提出考虑填充墙加固后刚度增强效应的建模方法。利用SAP2000建立了加固前后用于多遇地震工况、设防地震工况及罕遇地震工况的分析模型,并选取了桥头堡在1974年经历的实际地震激励时程及El-Centro地震激励时程作为激励进行了加固前后结构的抗震性能分析比较。研究发现,填充墙加固后桥头堡的抗震性能有了明显提升,其位移响应峰值约下降8%~23%,层间位移角响应峰值约下降12%~22%,而且桥头堡结构在设防地震情况下2个方向的层间位移角均满足了规范要求。另外,在罕遇地震工况下,未加固的填充墙开裂会使结构的扭转刚度下降,而填充墙加固可有效提升结构的扭转刚度,降低桥头堡在地震时发生扭转振动的概率。这2种地震荷载激励的分析结果差异约在3%~21%不等,且响应峰值出现的位置也有一些不同,故对桥头堡进行抗震时程分析时建议选取多条地震波输入综合分析。研究成果可为同类型的钢筋混凝土建筑遗产的抗震加固提供借鉴和参考。     

Ethnographic reflections on ‘oppositional heritage discourse’ in two post-earthquake Italian cities

This article explores the politicisation of cultural heritage during the aftermath of the 1980 earthquake in Naples and the 2009 earthquake in L’Aquila. It begins by critically addressing the positions of Tomaso Montanari and Salvatore Settis, two prominent heritage intellectuals at the forefront of national campaigns to restore the damaged historic centre of L’Aquila. Both have been instrumental in shaping an ‘oppositional heritage discourse’ in Italy that underscores the civic virtues of the nation’s cultural patrimony while simultaneously railing against its marketisation. Reflecting upon observations in L’Aquila, where locals involved in protests at government inaction have been scolded by fellow inhabitants for their lack of obeisance to cultural heritage, and drawing on longstanding ethnographic research in Naples, where heritage campaigns against redevelopment in the historic centre in the 1980s were later incorporated into an ambitious regeneration agenda, the article argues that this oppositional heritage discourse is not only premised upon idealist notions of collective identity but also, as a result of its attempts to legislate the boundaries of heritage citizenship and its disavowal of philologically incorrect relationships with historic centres, it ultimately provides tacit support to the very same neoliberal urban processes against which it claims to take a stand.     

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.     

MICROZONATION OF THE EXPECTED SEISMIC SITE EFFECTS ACROSS PORT VILA,VANUATU

The city of Port Vila, Vanuatu, is located in one of the most active seismic regions on earth. Earthquakes are felt frequently and, due to very rapid plate convergence rates, return period of large earthquakes (M>6) in the New Hebrides Benioff zone can be less than 10 years. Even though Port Vila does not lie on an identified seismic fault zone, strong motions by nearby earthquakes have to be expected due to the city's geographical location close to the plate boundary of New Hebrides convergence zone. An accurate estimation of the seismic ground motion across the city is of prime importance for urban developments and mitigation of earthquake risk. Following many examples of monitored strong earthquakes in the current century, it is evident that the local site effects may have a dominant contribution to the intensity of damage and destruction. In this study we focussed on the first stage of associating site effects and seismic hazard by preparing a microzonation map for Port Vila. The seismic microzonation of the city has been carried out to provide a detailed map of the zones that exhibit site effects in terms of resonance frequencies and approximated amplification of the ground shaking. Having in mind that these data will be used in improving building design to sustain strong ground motions, our analysis is limited to the frequency band of 1–10 Hz, corresponding to the expected resonance of different types of buildings in Port Vila. The Nakamura technique has been used to estimate site amplification effects from single station noise recordings. Interestingly, excluding one site located on an old dump zone, the amplification factors at about the 100 sites surveyed in Port Vila remain below 3 with an average well below 2 in the 1 to 10 Hz frequency band. These results suggest that there is no significant Vs velocity change in consequently layered material and that the uppermost sedimentary layers in the surveyed down town area are relatively thin. These observations are in agreement with the mapping of limestone terraces throughout Port Vila area. However, both the surface geology and results from seismic zonation indicate a thicker (up to several tens of meters) sedimentary cover around the Bauerfield airport and in the Mele terrace zone. Low resonance frequencies (around and below 1 Hz) and amplification factor of the order of 5 were observed over this large area, immediately outside Port Vila. Any building development in this area should take these results into account.     

Site Classification Assessment for Estimating Empirical Attenuation Relationships for Central-Northern Italy Earthquakes

The aim of this article is to investigate the ground motion attenuation of the most industrialized and populated regions of Italy, evaluating the capability of different approaches to estimate site dependent models. The 5.2 local magnitude earthquake on November 24, 2004 shocked the areas of Northern Italy producing damage of about 215 million euros. The data set, including 243 earthquakes of local magnitude up to 5.2, has been collected in the period December 2002–October 2005 by 30 three-component seismic stations managed by Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Milano (INGV-MI). Empirical attenuation relationships have been estimated for horizontal peak ground velocity (PGHV), acceleration (PGHA), displacement (PGHD), and for response spectral acceleration (SA) for periods between 0.1 and 1.5 s. To estimate suitable attenuation models, in particular for sites characterized by thick sedimentary geological formations, a soil discrimination based on EU8 code can lead to wrong evaluations. On the contrary, a classification based on H/V spectral ratios of seismic ambient noise (NHV) allows the models to fit better real and predicted data and to reduce the uncertainties of the process. For each receiver, NHV have been strengthened by additional H/V spectral ratio of earthquake data (EHV), calculated considering different portions of the analysed signals. In order to validate the PGHA attenuation relationship for greater magnitudes, accelerometric records, relative to Central-Northern Italy strong motions occurring in the last 30 years, have been collected and superimposed to our attenuation curves.     

Impact of Vertical Ground Excitation on a Bridge with Footing Uplift

Ground motions recorded in the epicentral region of an earthquake often have a strong vertical component with dominant high frequencies. Damage to bridges in near-source regions due to strong vertical ground motion has been reported. The beneficial effects of footing uplift on structural performance in form of reduction of seismic response of structural members have been confirmed in previous research. The uplift of bridge piers has been utilised in a very limited number of bridge structures, e.g., the South Rangitikei railway bridge in New Zealand. However, the near-fault seismic behaviour of bridges with footing uplift has been even less addressed. In this study shake table investigations were carried out on the response of a single-span bridge model with footing uplift subjected to simultaneous vertical and horizontal excitations. Near-fault ground motions recorded in the Canterbury earthquake sequences of 2010 and 2011 were used. The experimental results show that inclusion of vertical ground motions produce stronger axial force in the pier and larger bending moment in the deck. Concurrent horizontal and vertical excitations may also cause more frequent footing uplift than the solely horizontal excitations.     

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.     

A Fast and Efficient Simulation of the Far-Fault and Near-Fault Earthquake Ground Motions Associated with the June 17 and 21, 2000, Earthquakes in South Iceland

The two M_w 6.5 earthquakes on June 17 and 21, 2000, respectively, in the populated South Iceland Seismic Zone (SISZ) significantly augmented the Icelandic database of strong ground motions, and several strong velocity pulses were recorded at near-fault sites. The strong motions are interpreted via the Specific Barrier Model (SBM) and a mathematical model of near-fault velocity pulses. The data indicates self-similar source scaling and significantly greater attenuation of seismic waves than in other interplate regions. Through inversion of the data a new attenuation function for the SISZ has been adopted, which results in unbiased simulations. For the first time, the characteristics of the recorded near-fault pulses have been identified and compared to the worldwide database of such records. The SBM and the near-fault pulse model combine naturally in a fast and efficient synthesis of realistic, broad-band strong ground motions in the far-fault and near-fault region. Such simulations are showcased for the June 2000 earthquakes and indicate that the modeling approach adopted in this study is an effective tool for the estimation of realistic earthquake ground motions in the SISZ.     

FINITE FAULT MODELLING OF NEAR-FIELD ROCK MOTIONS IN THE NEW MADRID SEISMIC ZONE

Due to lack of strong motion records, point-source and finite-fault models have been used to simulate far-field motions at Memphis and St. Louis Cities from earthquake events in the New Madrid Seismic Zone. However, near-field rock motions and their associated uncertainties have never been studied within this zone. The objectives of this study are to develop a simple procedure to account for the uncertainty effect of earthquake source parameters, to analyze the sensitivity of near-field rock motions to input source parameters, and finally, to generate rock motions at two sites located within 11 km from the southwestern segment (strike-fault) and a third site bove the Reelfoot Rift (reverse fault) using a well-validated finite-fault simulation program; FINSIM. An equal-weight logic tree was developed to ensure that the assumed uncertainties are within physical, geological, and seismological constraints. For each site, 100 acceleration time histories with various combinations of parameter uncertainties were respectively simulated for an earthquake of M _w 7.0, 7.5, and 8.0 from each of the two faults. Their average spectral accelerations were in good agreement with those derived from the attenuation relation-ships representative to the Central and Eastern United States. Numerical simulations indicated that spectral accelerations are sensitive to the slip velocity, depth to top of fault, fault strike, slip distribution, and hypocentre location along the strike.     

Seismic History of the Church of San Pietro Di Coppito in L’Aquila

After the terrible 18th-century earthquakes—in L’Aquila in 1703, Lisbon in 1755, and Reggio Calabria in 1783—specific anti-seismic precepts were introduced in the rules of the art of masonry construction. Scrupulously adhered to in the first years after the earthquake, those precepts gradually ceased to be used until they were almost completely forgotten, centuries later, by which time the earthquake had become a distant memory. The church of San Pietro di Coppito, one of the most important churches of L’Aquila, is emblematic of this singular process. Deeply transformed in accordance with new anti-seismic construction techniques after it was particularly badly damaged in the terrible 1703 earthquake, the church was subjected, in the 1970s, to drastic alterations by the Commissioner Mario Moretti, who demolished all the baroque additions and redesigned it in the “medieval Abruzzo” style, eliminating in the process the intelligent anti-seismic provisions introduced in the 18th century. In addition to documentary purposes, this work aims to underline the effectiveness of this early 18th-century example of anti-seismic engineering in the belief that the constructive solutions it employed could still form a valid architectural and structural model in view of the massive restoration task for which, unfortunately, L’Aquila is still waiting today.     

Temporal change in groundwater level following the 1999 (Mw = 7.5) Chi-Chi earthquake, Taiwan

We examine the post‐seismic change in the groundwater level following the 1999 (M_w = 7.5) Chi‐Chi earthquake in central Taiwan, as recorded by a network of 70 evenly distributed hydrological stations over a large alluvial fan near the epicenter. Four types of post‐seismic responses may be distinguished. In type 1, the groundwater level declined exponentially with time following a coseismic rise. This was the most common response in the study area and occurred in unconsolidated sediments on the Choshui River fan. In type 2, the groundwater level rose exponentially with time following a coseismic fall. This occurred in the deformed and fractured sedimentary rocks in the foothills near the Chelungpu fault that ruptured in the Chi‐Chi earthquake. In type 3, the groundwater level continued to decline with time following a coseismic fall. This also occurred in the deformed and fractured sedimentary rocks near the ruptured fault. Finally, in type 4, the groundwater level, following a coseismic rise, stayed at the same level or even rose with time before it eventually declined. This occurred mostly in unconsolidated sediments along the coast of central Taiwan and along the Peikang Stream. We analyze these post‐seismic responses by using a one‐dimensional model. Together with the results from well test, the analysis show that the type 1 response may be explained by an aquifer model with coseismic recharge and post‐seismic subhorizontal discharge across a length of 500–5000 m; the type 2 response may be explained by a model of coseismic discharge and post‐seismic recharge from surface water; the type 3 response may be explained by a model of coseismic discharge and post‐seismic subhorizontal discharge across a length of 500–5000 m; and the type 4 response may be explained by a model of coseismic recharge and sustained post‐seismic recharge from surface water. The characteristic time for the post‐seismic changes is similar to that for the groundwater‐level decline during dry seasons before the earthquake, suggesting that there was no earthquake‐induced changes in the aquifer properties (i.e. hydraulic conductivity), confirming the earlier results from recession analyses of the post‐seismic streamflow elsewhere after several earthquakes.     

关于建立国内馆藏文物防震应急管理体系的探讨

我国地处环太平洋地震带和欧亚地震带间,因地震导致的馆藏文物损毁现象时有发生。近年来,我国馆藏文物防震技术研究取得了不少成果,并在部分博物馆成功进行了一体化防震示范应用。但总体而言,馆藏文物防震风险预防和应急管理水平仍相对滞后,部分博物馆存在防震措施不合理、日常管理匮乏、应急能力不足等现象,亟待健全馆藏文物防震应急管理体系,其中应急预案的编制尤为重要。通过建立完善的应急管理体系,博物馆能够全面提高防震意识和应急处置能力,合理利用各类防震措施降低潜在风险,更好地保护馆藏文物。     

Attenuation Relationships for Iran

The purpose of this study is to derive the attenuation relationships for PGA, PGV, and EPA parameters for areas within the seismic zones of Zagros, Alborz and Central Iran with rock and soil substructures. In order to do so, at first the available scientific data including the methods used for deriving attenuation relationships and the parameters involved have been gathered. Afterwards, all the efforts have been focused on gathering a thorough catalogue of earthquakes occurred in Iran. In this regard, a majority of the available catalogs in Iran have been gathered and corrected through different methods and finally a set of 89 earthquake events including 307 earthquake records with reliable data was chosen.

Since in order to derive the attenuation relationships it is essential to extract the parameters from the acceleration records, a great effort was placed on gathering the earthquake acceleration records of Iran. This resulted in building a database of a majority of the earthquake records up to the year of 2004. Afterwards, correction methods applicable to earthquakes records of Iran considering the type of machines used and the ground type were examined which resulted in certain guidelines for correction of earthquake acceleration record data related to Iran.

In the next step the needed parameters were extracted from the earthquake acceleration record data which were consequently divided into two seismic zones of Zagros, and Alborz and Central Iran according to tectonic conditions. After examination of the parameters and choosing the most appropriate among them, the attenuation relationships were derived for such parameters.     

Scalar Structure-Specific Ground Motion Intensity Measures for Assessing the Seismic Performance of Structures: A Review

The assessment of the seismic performance depends on the choice of the earthquake Intensity Measure (IM). During the past years many IMs, which take into account not only earthquake characteristics but also structural information, have been proposed. However, no consensus on which IM is the best predictor of the seismic response exists. Along these lines, the objective of this paper is to present the various developed scalar structure-specific seismic IMs and the problems associated with their use in practice, so that the engineer may become familiar with them and their implications in the context of Performance-Based Earthquake Engineering.     

Nobel laureates at the Stazione Zoologica Anton Dohrn: phenomenology and paths to discovery in neuroscience

The practice of science usually involves more than a solitary genius in a solitary room, coping with the problem of her/his life. From the second half of the 19th century onwards, scientific research, especially in the field of the Natural Sciences, has grown into a more and more complex practice, which often entangles very special needs, in terms of research objects, techniques, sources, and perspectives. A few special places, such as the Stazione Zoologica di Napoli, have represented in this period the focal points of an ever growing international scientific network, promoting independent research, exchange and diffusion of novel practices and techniques and unrestricted confrontation. The so-called "Naples experience" has been cited by a large number of renowned scientists of the last two centuries as a key moment in their scientific life. Here we have tried to test it against the experience of three great scientists par excellence, i.e. three Nobel laureates (T. H. Morgan, Otto Warburg, J. D. Watson). The different experiences they have had at Naples represent, in our view, three different moments of the professional life of almost every scientist. Therefore, we have chosen to present them as a phenomenology. The final section is dedicated to a survey of the Zoological Station's contribution to neurosciences, especially to the Naples experience of the Nobel Prize winner Sir Bernard Katz and his assistant Ricardo Miledi, between 1965 and 1970. Their work on the squid at Naples allowed probing and quantitative refinement of results already obtained on different animals and contributed to reinforce the long lasting neurophysiological tradition of the institute.     

故宫灵沼轩的动力特性及抗震性能研究

故宫灵沼轩是我国最早建造的钢铁-砌体组合结构之一,具有重要的历史、艺术和科学价值。为了评估灵沼轩在地震作用下的结构安全状况,建立了灵沼轩结构的三维有限元模型,并对其进行了动力特性和地震时程分析,得出了其固有频率、模态振型、地震位移响应和地震应力响应。结果表明:灵沼轩整体结构布置对称性较高,扭转刚度较大,对抗震较为有利;在8度多遇地震、设防地震和罕遇地震作用下,灵沼轩的金属结构部分及砌体结构部分的顶点位移和层间位移角均符合现行规范要求,砌体结构部分的第三主应力响应均小于材料的抗压强度,不存在压溃风险。在8度多遇地震和设防地震作用下,砌体结构部分的第一主应力响应均小于材料的抗拉强度,结构不会发生拉裂。但在8度罕遇地震作用下,砌体结构的部分位置拉应力超过材料的抗拉强度,这些位置存在开裂危险。最后,综合动力特性和抗震性能分析的结果,提出了灵沼轩的抗震加固建议。