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1.
The new European Macroseismic Scale 1992 (EMS) is applied to intensity estimation of data collected in field investigations of the 26 June 1993 Pollina (northern Sicily) earthquake and the results are compared with those obtained using the MSK-81 scale. The highest intensity estimated (VI–VII) fits with the low magnitude value (M
L
= 4.7) and the low resistance level of buildings is responsible for some unexpected severe damage, thus raising the seismic vulnerability of the area. The tectonic framework shows significant elements of recent activity accounting for the frequent seismicity. The study also evaluated the validity of using vulnerability classes of buildings as defined in the EMS scale in the intensity assessment of historical earthquakes of the area. 相似文献
2.
Seismic risk scenarios are obtained for an informal settlement in Mérida (Venezuela), which is representative of an important
number of urban areas in earthquake-prone regions of the developing world. The vulnerability indices of the buildings range
between 0.64 and 0.80 on a scale of 0 to 1. In an intensity IX earthquake scenario, more than 32% of the buildings would suffer
damage of grade 4 (extensive) or greater. A structural analysis of the buildings in the study area shows that they are unsafe
for gravity loads, and that the seismic demands exceed the strength of the constructions. Simple and comparatively inexpensive
measures can improve the seismic performance of these buildings; the vulnerability can be reduced by about 51%. In an intensity
IX earthquake scenario, the expected economic loss before retrofitting the buildings is US5.36 million, with 275 fatalities; once retrofit has been carried out, the resulting figures are US5.36 million, with 275 fatalities;
once retrofit has been carried out, the resulting figures are US0.39 million and 10 fatalities. Retrofit would cost US1.04 million, whereas reconstruction would cost US1.04
million, whereas reconstruction would cost US19 million. 相似文献
3.
The expected fraction of buildings lost in the event of an earthquake of a given intensity can be considered as a useful indicator of the seismic vulnerability of a small urban nucleus and can be used for the evaluation of seismic risk on a regional scale. This work describes a procedure for quantifying this indicator through data obtained from the buildings which constitute the nucleus during rapid on-site surveys. The knowledge on which the procedure is based is that given by the observed vulnerability of old Italian centres. 相似文献
4.
Many tens of severe earthquake damage patterns were revealed at the ancient city of Ayla. The seismic deformation patterns
are of various types, including systematic tilting of walls, systematic shifting and rotation of wall fragments and individual
stones, arch deformations and joints crossing two or more stones. Features of later repair, supporting walls and secondary
use of building stones suggest that the damage patterns can be explained by two historical devastating earthquakes: (I) revealed
in the constructions built during the late Rashidun period (644–656 A.D.); (II) revealed in the structures restored and/or
built during the Fatimid period (1050–1116 A.D.). The maximum observed intensity of both earthquakes at the studied site was
not less than IX (EMS98 scale). The sources of the seismic events were probably the Dead Sea Transform and Wadi Araba Faults
that cross the site obliquely. The last 1995 Nuweiba earthquake with maximum observed intensity VIII has also left its clear
traces in the excavated ancient Ayla buildings. The severity of the destruction was significantly increased because of site
effects. 相似文献
5.
Al Hoceima is one of the most seismic active regions in north of Morocco. It is demonstrated by the large seismic episodes reported in seismic catalogs and research studies. However, seismic risk is relatively high due to vulnerable buildings that are either old or don’t respect seismic standards. Our aim is to present a study about seismic risk and seismic scenarios for the city of Al Hoceima. The seismic vulnerability of the existing residential buildings was evaluated using the vulnerability index method (Risk-UE). It was chosen to be adapted and applied to the Moroccan constructions for its practicality and simple methodology. A visual inspection of 1102 buildings was carried out to assess the vulnerability factors. As for seismic hazard, it was evaluated in terms of macroseismic intensity for two scenarios (a deterministic and probabilistic scenario). The maps of seismic risk are represented by direct damage on buildings, damage to population and economic cost. According to the results, the main vulnerability index of the city is equal to 0.49 and the seismic risk is estimated as Slight (main damage grade equal to 0.9 for the deterministic scenario and 0.7 for the probabilistic scenario). However, Moderate to heavy damage is expected in areas located in the newer extensions, in both the east and west of the city. Important economic losses and damage to the population are expected in these areas as well. The maps elaborated can be a potential guide to the decision making in the field of seismic risk prevention and mitigation strategies in Al Hoceima. 相似文献
6.
B. C. Papazachos Ch. A. Papaioannou B. N. Margaris N. P. Theodulidis 《Natural Hazards》1993,8(1):1-18
A semi-probabilistic approach to the seismic hazard assessment of Greece is presented. For this reason, a recent seismotectonic model for shallow and intermediate depth earthquake sources, based on historical as well as on instrumental data, was used. Different attenuation formulae were proposed for the macroseismic intensity and the strong ground motion parameters for the shallow and the intermediate focal depth shocks. The data were elaborated in terms of McGuire's computer program, which is based on the Cornell's method.A grid of equally spaced points at 20 km distance was made and the seismic hazard recurrence curves for various parameters of the seismic intensity was estimated for each point. Finally, seismic hazard maps for the area of Greece were compiled utilizing the entire range of recurrence curves. These maps depict areas of equal seismic hazard and for every area the analytical relations of the typeSI =f(Tm), whereSI is a seismic intensity parameter andTm is the mean return period, were determined. 相似文献
7.
Jairo A. Valcárcel Miguel G. Mora Omar D. Cardona Lluis G. Pujades Alex H. Barbat Gabriel A. Bernal 《Natural Hazards》2013,69(1):845-868
This article presents a methodology for an estimate of the benefit cost ratio of the seismic risk reduction in buildings portfolio at broadscale, for a world region, allowing comparing the results obtained for the countries belonging to that region. This methodology encompasses (1) the generation of a set of random seismic events and the evaluation of the spectral accelerations at the buildings location; (2) the estimation of the buildings built area, the economic value, as well as the classification in structural typologies; (3) the development of vulnerability curves for each typology; (4) the estimation of the annual average loss of the buildings portfolio in the current conditions as well as in the case of a hypothetical structural intervention. The benefit cost ratio is estimated as the difference between the estimates of the present value of these two annual average losses, divided by the retrofitting costs. This methodology has been applied to the portfolio of public schools of 14 countries of Latin America and the Caribbean, for evaluating the feasibility of the seismic risk reduction at a national scale. 相似文献
8.
9.
The January 6, 2006, Balei earthquake as a reflection of the present tectonic activity of the east Trans-Baikal Region 总被引：1，自引：0，他引：1
Mel’nikova V. I. Radziminovich Ya. B. Gileva N. A. Radziminovich N. A. Papkova A. A. 《Doklady Earth Sciences》2011,437(2):552-556
The results of detailed studies of the January 6, 2006, Balei earthquake (K
p = 13.1, M
b = 4.7 [7]), which occurred in an almost aseismic area of the east Trans-Baikal Region, are presented. The focal mechanism
and dynamical characteristics of the focus are considered, and the structural-tectonic position of the focus is analyzed.
It is supposed that the focus of this seismic event coincides with an activated segment of the northwest-striking Balei-Darasun
fault. The maximal observed macroseismic intensity was 5–6 points by the MSK-64 scale (in the town of Baleis). The origination
of foci for the earthquake with such intensity and magnitude takes place substantially owing to subhorizontal northeastern
compression, the varied-rank block structure of the medium, and low rate values of tectonic motions; on aggregate, all these
factors promote the accumulation of stresses in the Earth’s crust. The obtained data can be useful for the purpose of assessment
in seismic danger of the region. 相似文献
10.
A deterministic seismic risk and monetary loss model is presented for the capital of Santorini volcanic Island, the town of Fira, on a building block scale. A local seismic source of M5.6 inferred from a recent volcano unrest in 2011–2012, detailed seismic vulnerability of 435 buildings and site conditions deduced from free-field ambient noise measurements were combined toward assessing the EMS-98 damage grade and its probability to occur. The seismic scenario yielded no damage or slight damage for 84% of the buildings, 16% of the constructions are expected to present moderate-to-heavy damage, while the economic loss amounts to 4 million euros. Although the model predicts low damage and direct economic loss, interaction with the touristic business activities might produce cascade side effects for the economy of the island and consequently Greece’s GDP, an important part of which emanates from Santorini. 相似文献
11.
Earthquake disaster is still the number one among all natural disasters, particularly, in terms of destructive power in causing deaths. Can earthquake engineers control seismic casualties through the seismic design of buildings? For this purpose, a conception of casualty control based seismic design is presented and a “two-step decision-making” method is proposed for determining the optimum seismic design intensity (or ground-motion) for controlling both seismic death and economic losses. The key problems in establishing the model are to determine the appropriate socially acceptable level of earthquake mortality and establish the corresponding objective function and /or constraint conditions in determining the optimum seismic design intensity. Ten different grades of socially acceptable mortality are suggested and the final socially acceptable mortality level was proposed for seismic design based on a questionnaire that was distributed nationwide in China. Finally, the method was applied to eight cities with different seismic hazard in China and the effects of various grades of acceptable earthquake mortality on seismic design intensity are analyzed. 相似文献
12.
A probabilistic assessment of the seismic hazard in Turkey 总被引：1，自引：0，他引：1
13.
Carlos López Casado Jesús Garrido José Delgado José Antonio Peláez Jesús Henares 《Natural Hazards》2018,93(1):153-167
The January 25, 2016, Mw 6.3 Alborán Sea earthquake shook the autonomous city of Melilla (Spain) with a macro-seismic intensity of VI (EMS-98). In spite of this low intensity, significant non-structural damages were reported, whose cost was estimated in more than 13 million euros. The damages were concentrated in the modernist district, which is considered the most important and valuable part of the city. This scenario is not new in Melilla, since historical and instrumental seismicity studies based on intensities felt in Melilla have revealed that earthquakes with intensities of V–VI have a return period of approximately 25 years. However, seismic microzonation studies have not been carried out so far. In this paper, we present a seismic microzonation study based on seismic noise measurements and the foreshock, mainshock and aftershock records of the January 25, 2016, earthquake. The seismic signals were processed using the horizontal-to-vertical spectral ratio (HVSR) technique. The frequency amplification results were correlated with geological formations, and after that they were correlated with the distribution of damages. The lagoon and the recent alluvial deposits show the maximum number of damaged buildings and maximum frequency amplifications of 2–8 between 2 and 7 Hz. In the coastal deposits, some amplification in the same frequency range has been observed, but other formations show a minimum number of damaged buildings and a flat spectral response ratio. Two important factors in this damage pattern are the high vulnerability of ornamental facades characteristics (non-structural elements) of the modern architecture buildings and their location on the lagoon and the recent alluvial deposits where maximum site amplification is reached. 相似文献
14.
This paper is concerned with an investigation of the damage to residential buildings in two areas within Gilan and Zanjan provinces, Iran, caused by the Manjil-Rudbar earthquake of 20 June 1990. A statistical correlation between the observed ground motion and the damage to the residential buildings is derived for overall damaged buildings and expressed as the vulnerability function. The loss function is calculated by combining the seismic hazard with the vulnerability function.The study of vulnerability and annual seismic hazard shows that the specific annual risk for the range of motion of 0.18 to 0.5 g is equal to 0.02. This indicates that the specific risk for semi-engineered residential buildings with a lifetime of 20 years is about 33%. This study also shows that in large cities, such as Tehran, located in seismic areas, the extent of damage according to the vulnerability function will be 45 and 70% for expected maximum accelerations of 0.3 and 0.4 g, respectively. 相似文献
15.
L&#;pez Casado Carlos Garrido Jes&#;s Delgado Jos&#; Pel&#;ez Jos&#; Antonio Henares Jes&#;s 《Natural Hazards》2017,93(1):153-167
The January 25, 2016, Mw 6.3 Alborán Sea earthquake shook the autonomous city of Melilla (Spain) with a macro-seismic intensity of VI (EMS-98). In spite of this low intensity, significant non-structural damages were reported, whose cost was estimated in more than 13 million euros. The damages were concentrated in the modernist district, which is considered the most important and valuable part of the city. This scenario is not new in Melilla, since historical and instrumental seismicity studies based on intensities felt in Melilla have revealed that earthquakes with intensities of V–VI have a return period of approximately 25 years. However, seismic microzonation studies have not been carried out so far. In this paper, we present a seismic microzonation study based on seismic noise measurements and the foreshock, mainshock and aftershock records of the January 25, 2016, earthquake. The seismic signals were processed using the horizontal-to-vertical spectral ratio (HVSR) technique. The frequency amplification results were correlated with geological formations, and after that they were correlated with the distribution of damages. The lagoon and the recent alluvial deposits show the maximum number of damaged buildings and maximum frequency amplifications of 2–8 between 2 and 7 Hz. In the coastal deposits, some amplification in the same frequency range has been observed, but other formations show a minimum number of damaged buildings and a flat spectral response ratio. Two important factors in this damage pattern are the high vulnerability of ornamental facades characteristics (non-structural elements) of the modern architecture buildings and their location on the lagoon and the recent alluvial deposits where maximum site amplification is reached.
相似文献16.
The data presented in this paper show that in historical time the Chuy Basin in Kyrgyzstan was repeatedly subjected to strong earthquakes, which affected the inhabitants and the economic and political situation at that time. The deformed buildings in the Novopokrovka site of ancient settlements situated in the central part of the basin unequivocally indicate seismic damage and subsequent abandonment of the settlement. The earthquake happened at the end of the Karakhanid epoch (the end of the 12th century A.D.). The intensity of seismic oscillations (I = VIII–IX) at the site was reinforced by unfavorable engineering geology conditions. The source of the earthquake was probably related to displacements along the piedmont Ysyk-Ata Fault located to the south of the site. 相似文献
17.
Earthquake characteristics and building damage in high-intensity areas of Wenchuan earthquake II: Dujiangyan and Pengzhou City 总被引：1，自引：0，他引：1
On May 12, 2008, a massive earthquake occurred along the Longmen Mountain Central Fault in Sichuan Province, China, causing serious damages to buildings near the fault. As the Longmen Mountain Central Fault and the Anterior Fault both traversed Dujiangyan and Pengzhou cities, the seismic intensity in these areas reached levels IX?CXI. Therefore, these two cities were among the most seriously damaged regions. In this article, the types of damage to buildings in the two cities and their affiliated towns or villages are investigated and reported. It is found that the damage to a building is related to its structure type, distance from the faults, and so on. The results provide valuable information on the seismic resistance of buildings in similar areas. 相似文献
18.
The catastrophic 1883 earthquake at the island of Ischia (southern Italy): macroseismic data and the role of geological conditions 总被引：1，自引：0，他引：1
This article presents the results of a detailed study of the effects of the 1883 earthquake, which occurred at the island
of Ischia (Gulf of Naples) and produced the total destruction of buildings in the epicentral area (Casamicciola town). Despite
the moderate magnitude, this event was characterised by very high intensities (I
max = XI degree MCS) mainly due to the shallow depth of the source. The study of the earthquake shows that the intensities, which
decreased rapidly with distance, were affected by source directivity, according to the causative fault geometry and tectonic
structures, while local amplification of damage was observed where soft soils outcrop. The attenuation of seismic intensity
with distance was evaluated using the well-known relation of intensity versus epicentral distance (Blake’s method). The diverse
gradients of attenuation, observed in different directions, were ascribed to the various geological features of the shallow
crust of the island. In order to evaluate the role of geology in the damage level, we computed different attenuation models
for stiff and soft soils outcropping on the island. A systematic local amplification of about 1 MCS degree associated to the
presence of reworked tuffs was obtained. This study also shows the influence of geological conditions on the evaluation of
macroseismic data and supplies useful elements to derive a predictive map of potential site effects. 相似文献
19.
Urban earthquake disaster prevention is regarded as an integrated systematic engineering. Urban earthquake disaster prevention system is made up of all the earthquake disaster prevention activities. The concept and composition of urban earthquake disaster prevention system periphery were presented based on system periphery theory. A seismic risk-control mechanism model of system periphery was deduced using exchange rate of periphery as a dependent variable, and an observability–controllability model of system periphery was established and crystallized in its application to the quantitative analysis of practice problem. The input sets of urban earthquake disaster prevention system are determined as the maximum earthquake magnitude happened in or around the city, the measurable earthquake frequency, population density and fixed assets density. The inside state sets of urban earthquake disaster prevention system are determined as disaster resistant ability of buildings, disaster resistant ability of lifelines and investment dynamics in disaster prevention per urban built-up area. The system output is urban seismic risk. The calculative results show the model presented in this study can analyze the influence of system periphery intensity and inside state on seismic risk and can control urban seismic risk by adjusting the parameters of system periphery, the system inside state and human influence intensity. 相似文献
20.
V. M. Zobin E. I. Gordeev N. P. Kozyreva V. P. Mityakin V. N. Chirkova 《Natural Hazards》1991,4(4):327-344
This paper gives macroseismic and instrumental data on the 17 August 1983 Kamchatka earthquake which occurred in the center of the Kamchatka Gulf bend at a depth of 98 km with an epicentral intensity of VI–VII (MSK-64 scale), energy class 15, and magnitude MLH = 6.9. The focal mechanism represents a thrust along the inclined surface across the strike of the Kamchatka Gulf coastal line. The Primary-wave seismic moment M
0 is 6.3 × 1019 Nm, the Rayleigh wave M
0 is 1.6 × 1019 Nm, and the stress drop is 2.5 MPa. Copies of displacement and acceleration records are presented and the temporal and spatial distribution of the aftershocks is analyzed. 相似文献