Lessons from the 1985 Mexican earthquake

1986 ◽  
Vol 13 (5) ◽  
pp. 535-557 ◽  
Author(s):  
Denis Mitchell ◽  
John Adams ◽  
Ronald H. DeVall ◽  
Robert C. Lo ◽  
Dieter Weichert
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Soft Soil ◽  
Near Field ◽  
Lessons Learned ◽  
Background Information ◽  
Soil Conditions ◽  
National Committee ◽  
Severe Damage ◽  
Epicentral Area

Severe damage during the September 19, 1985 Mexican earthquake prompted a site visit by three engineers and two seismologists representing the Canadian National Committee on Earthquake Engineering. This paper includes background information on earthquake history of the region, details of the 1985 earthquake and its strong ground motion, subsoil conditions, and building code provisions. The team's observations of moderate damage in the epicentral area are consistent with the relatively low near-field accelerations (15% g). In the damaged parts of Mexico City, soft soil conditions amplified the ground motion and resulted in almost pure harmonic motion with a period of about 2 s. These characteristics, together with the long duration and high accelerations (20% g) caused severe damage to many structures, as is illustrated in the paper. Lessons learned from the earthquake together with the Mexican emergency code changes are discussed. Key words: seismic, earthquake, Mexico, soils, structures, codes.

scholarly journals Checking the site categorization criteria and amplification factors of the 2021 draft of Eurocode 8 Part 1–1

2021 ◽  
Author(s):  
Roberto Paolucci ◽  
Mauro Aimar ◽  
Andrea Ciancimino ◽  
Marco Dotti ◽  
Sebastiano Foti ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Shear Wave ◽  
Ground Motion ◽  
Shear Wave Velocity ◽  
Soft Soil ◽  
Site Amplification ◽  
Soil Conditions ◽  
Eurocode 8 ◽  
Site Specific ◽  
Amplification Factors

AbstractIn this paper the site categorization criteria and the corresponding site amplification factors proposed in the 2021 draft of Part 1 of Eurocode 8 (2021-draft, CEN/TC250/SC8 Working Draft N1017) are first introduced and compared with the current version of Eurocode 8, as well as with site amplification factors from recent empirical ground motion prediction equations. Afterwards, these values are checked by two approaches. First, a wide dataset of strong motion records is built, where recording stations are classified according to 2021-draft, and the spectral amplifications are empirically estimated computing the site-to-site residuals from regional and global ground motion models for reference rock conditions. Second, a comprehensive parametric numerical study of one-dimensional (1D) site amplification is carried out, based on randomly generated shear-wave velocity profiles, classified according to the new criteria. A reasonably good agreement is found by both approaches. The most relevant discrepancies occur for the shallow soft soil conditions (soil category E) that, owing to the complex interaction of shear wave velocity, soil deposit thickness and frequency range of the excitation, show the largest scatter both in terms of records and of 1D numerical simulations. Furthermore, 1D numerical simulations for soft soil conditions tend to provide lower site amplification factors than 2021-draft, as well as lower than the corresponding site-to-site residuals from records, because of higher impact of non-linear (NL) site effects in the simulations. A site-specific study on NL effects at three KiK-net stations with a significantly large amount of high-intensity recorded ground motions gives support to the 2021-draft NL reduction factors, although the very limited number of recording stations allowing such analysis prevents deriving more general implications. In the presence of such controversial arguments, it is reasonable that a standard should adopt a prudent solution, with a limited reduction of the site amplification factors to account for NL soil response, while leaving the possibility to carry out site-specific estimations of such factors when sufficient information is available to model the ground strain dependency of local soil properties.

A Case Study of Accelerometric Records Analysis of May 21st, 2003, Boumerdes (Algeria) Earthquake

2013 ◽  
Vol 4 (2) ◽  
pp. 34-52 ◽  
Author(s):  
Abdelwahab Mourad Khellafi ◽  
Zamila Harichane ◽  
Hamid Afra ◽  
Amina Sadouki
Keyword(s):  
Earthquake Engineering ◽  
Epicentral Distance ◽  
Near Field ◽  
Response Spectra ◽  
Soil Conditions ◽  
Eurocode 8 ◽  
Earthquake Epicenter ◽  
Ground Acceleration ◽  
Design Spectra ◽  
The North

On May 21st, 2003, the north Algeria was stricken by a 6.8 magnitude earthquake which was felt over a distance of 250 km from the epicenter, which is localized in Mediterranean Sea at 10 km from the coast. During this event, several ground accelerations were recorded by the instrumentation network of the National Center of Applied Research in Earthquake Engineering (CGS). The records analysis revealed an important difference in peak ground acceleration (PGA) between two close stations (0.58g and 0.33g, respectively, in East-West direction) at about 20 km from the earthquake epicenter. Also, two other record stations, located in the Mitidja basin, at about 29 km and 86 km from the earthquake epicenter, respectively, showed a high level of acceleration: PGAs of 0.54g and 0.16g. So, the authors attempt in this paper to analyze these records through the characteristics of strong ground motions, the effects of different parameters such as damping ratios, soil conditions and epicentral distance on normalized response spectra. Also, the quantification of site effects during this earthquake is analyzed. Then, the authors compare the near-field mean response spectra obtained during this earthquake with the Algerian seismic design spectra (RPA99 – 2003 version) and with two other well-known design spectra: Eurocode 8 and UBC97 in order to contribute to the future revision of RPA99.

scholarly journals The September 19th, 2017 Puebla, Mexico earthquake

2020 ◽  
Vol 53 (3) ◽  
pp. 150-172
Author(s):  
Samuel Roeslin ◽  
Hugón Juárez-Garcia ◽  
Kenneth Elwood ◽  
Rajesh Dhakal ◽  
Alonso Gómez-Bernal
Keyword(s):  
Earthquake Engineering ◽  
Structural Damage ◽  
Risk Mitigation ◽  
Soft Soil ◽  
American Concrete Institute ◽  
Mitigation Measures ◽  
Soil Conditions ◽  
Local Site Effects ◽  
Local Site ◽  
Mexico Earthquake

This report presents the observations and findings following the 2017 Puebla earthquake that occurred inMexico on September 19th, 2017. The reconnaissance mission was a collaboration between the New ZealandSociety of Earthquake Engineering (NZSEE), the Universidad Autónoma Metropolitana (UAM) Azcapotzalco,the American Concrete Institute (ACI) Disaster Reconnaissance team, and the Colegio de Ingenieros Civilesde Mexico (CICM). During the earthquake, 77 buildings suffered partial or total collapse and more than8,000 buildings experienced damage ranging from slight damage to significant structural damage necessitatingdemolition. As observed in previous earthquakes, the unique soil conditions of Mexico City resulted inextensive damage to the city’s infrastructure, primarily due to local site effects. The earthquake causedrelatively more damage to buildings built on transition and soft soil zones (i.e. between hard and deep softsoils) than those on hard soils.The NZSEE and UAM team focussed on areas with widespread and extensive damage. They also assessedthe performance of repaired and retrofitted buildings after the 1985 Michoacán earthquake. It was found thatthe lessons learnt from the 1985 Michoacán earthquake led to some risk mitigation measures which benefitedseveral buildings in the 2017 earthquake. Retrofitted buildings were found to have performed very well withlittle or no damage when compared to other buildings.

The SMART I Accelerograph Array (1980-1987): A Review

1987 ◽  
Vol 3 (2) ◽  
pp. 263-287 ◽  
Author(s):  
N. A. Abrahamson ◽  
B. A. Bolt ◽  
R. B. Darragh ◽  
J. Penzien ◽  
Y. B. Tsai
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Ground Motions ◽  
Near Field ◽  
Strong Motion ◽  
Response Spectra ◽  
Transform Faults ◽  
Engineering Research ◽  
Motion Data ◽  
Time Histories

SMART 1 is the first large digital array of strong-motion seismographs specially designed for engineering and seismological studies of the generation and near-field properties of earthquakes. Since the array began operation in September 1980, it has recorded over 3000 accelerogram traces from 48 earthquakes ranging in local magnitude ( ML) from 3.6 to 7.0. Peak ground accelerations have been recorded up to 0.33g and 0.34g on the horizontal and vertical components, respectively. Epicentral distances have ranged from 3 km 200 km from the array center, and focal depths have ranged from shallow to 100 km. The recorded earthquakes had both reverse and strike-slip focal mechanisms associated with the subduction zone and transform faults. These high quality, digital, ground motions provide a varied resource for earthquake engineering research. Earthquake engineering studies of the SMART 1 ground motion data have led to advances in knowledge in several cases: for example, on frequency-dependent incoherency of free-surface ground motions over short distances, on response of linear systems to multiple support excitations, on attenuation of peak ground-motion parameters and response spectra, on site torsion and phasing effects, and on the identification of wave types. Accelerograms from individual strong-motion seismographs do not, in general, provide such information. This review describes the SMART 1 array and the recorded earthquakes with special engineering applications. Also, it tabulates the unfiltered peak array accelerations, displays some of the recorded ground motion time histories, and summarizes the main engineering research that has made use of SMART 1 data.

Damage caused by the November 25, 1988, Saguenay earthquake

1990 ◽  
Vol 17 (3) ◽  
pp. 338-365 ◽  
Author(s):  
Denis Mitchell ◽  
René Tinawi ◽  
Tim Law
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Structural Damage ◽  
Poor Performance ◽  
Response Spectra ◽  
Unreinforced Masonry ◽  
National Committee ◽  
Base Shear ◽  
Acceleration Time Histories ◽  
Ground Motion Records

The November 25, 1988, Saguenay earthquake prompted a site visit by a team representing the Canadian National Committee on Earthquake Engineering. This paper contains selected ground motion records in the form of acceleration-time histories, obtained from the Geological Survey of Canada, and corresponding response spectra. The horizontal acceleration spectrum obtained for Chicoutimi is compared with the design base shear coefficients from the 1980, 1985, and 1990 National Building Codes of Canada. Failures of natural slopes and embankments as well as both architectural and structural damage are discussed. The significant role played by the presence of soft subsoil in amplifying the ground motion and resulting damage is illustrated. Although no major structural failures occurred, there were many examples of poor performance, and in some cases failures, of unreinforced masonry walls. Concerns are expressed over the abundance of unreinforced masonry, particularly in schools and buildings such as hospitals, for which postdisaster performance must be ensured. Key words: earthquake, Saguenay, soils, structures, codes, masonry.

scholarly journals The "Eje Cafetero" earthquake, Colombia of January 25, 1999

2000 ◽  
Vol 33 (1) ◽  
pp. 1-29 ◽  
Author(s):  
J. I. Restrepo ◽  
H. A. Cowan
Keyword(s):  
Emergency Response ◽  
Earthquake Engineering ◽  
Ground Motions ◽  
Soft Soil ◽  
Response Strategy ◽  
Soil Conditions ◽  
Shallow Earthquake ◽  
Topographical Effects ◽  
National Emergency ◽  
Shallow Focus

A moderate shallow earthquake struck the west central region of Colombia on 25 January 1999. The earthquake caused damage of approximately NZ $3.7 billion (US $1.9 billion). 1,230 deaths. About 200,000 people were made homeless. The level of damage and losses can be attributed to the shallow focus of the earthquake and its proximity to the major towns, together with topographical effects and soft soil conditions, which amplified the ground motions in some areas. The lack of a well-co-ordinated, national emergency response strategy, and the severe impact of the event on the organisations and key individuals responsible for managing the emergency response in the affected area, impaired the emergency response in the aftermath. This paper summarises the main findings of a reconnaissance team to the region organised by the New Zealand Society for Earthquake Engineering.

Les dommages dus au tremblement de terre du Saguenay du 25 novembre 1988

1990 ◽  
Vol 17 (3) ◽  
pp. 366-394 ◽  
Author(s):  
René Tinawi ◽  
Denis Mitchell ◽  
Tim Law
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Structural Damage ◽  
Poor Performance ◽  
Response Spectra ◽  
Unreinforced Masonry ◽  
National Committee ◽  
Base Shear ◽  
Acceleration Time Histories ◽  
Ground Motion Records

The November 25, 1988, Saguenay earthquake prompted a site visit by a team representing the Canadian National Committee on Earthquake Engineering. This paper contains selected ground motion records in the form of acceleration-time histories, obtained from the Geological Survey of Canada, and corresponding response spectra. The horizontal acceleration spectrum obtained for Chicoutimi is compared with the design base shear coefficients from the 1980, 1985, and 1990 National Building Codes of Canada. Failures of natural slopes and embankments as well as both architectural and structural damage are discussed. The significant role played by the presence of soft subsoil in amplifying the ground motion and resulting damage is illustrated. Although no major structural failures occurred, there were many examples of poor performance, and in some cases failures, of unreinforced masonry walls. Concerns are expressed over the abundance of unreinforced masonry, particularly in schools and buildings such as hospitals, for which postdisaster performance must be ensured. Key words: earthquake, Saguenay, soils, structures, codes, masonry.

scholarly journals An extended stochastic method for seismic hazard estimation

2015 ◽  
Vol 3 (12) ◽  
pp. 7555-7586
Author(s):  
A. K. Abd el-aal ◽  
M. A. El-Eraki ◽  
S. I. Mostafa
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Earthquake Engineering ◽  
Peak Ground Acceleration ◽  
Risk Mitigation ◽  
Stochastic Method ◽  
Soil Conditions ◽  
Seismic Sources ◽  
Ground Acceleration ◽  
Median Response

Abstract. In this contribution, we developed an extended stochastic technique for seismic hazard assessment purposes. This technique depends on the hypothesis of stochastic technique of Boore (2003) "Simulation of ground motion using the stochastic method. Appl. Geophy. 160:635–676". The essential characteristics of extended stochastic technique are to obtain and simulate ground motion in order to minimize future earthquake consequences. The first step of this technique is defining the seismic sources which mostly affect the study area. Then, the maximum expected magnitude is defined for each of these seismic sources. It is followed by estimating the ground motion using an empirical attenuation relationship. Finally, the site amplification is implemented in calculating the peak ground acceleration (PGA) at each site of interest. We tested and applied this developed technique at Cairo, Suez, Port Said, Ismailia, Zagazig and Damietta cities to predict the ground motion. Also, it is applied at Cairo, Zagazig and Damietta cities to estimate the maximum peak ground acceleration at actual soil conditions. In addition, 0.5, 1, 5, 10 and 20 % damping median response spectra are estimated using the extended stochastic simulation technique. The calculated highest acceleration values at bedrock conditions are found at Suez city with a value of 44 cm s−2. However, these acceleration values decrease towards the north of the study area to reach 14.1 cm s−2 at Damietta city. This comes in agreement with the results of previous studies of seismic hazards in northern Egypt and is found to be comparable. This work can be used for seismic risk mitigation and earthquake engineering purposes.

The Borah Peak, Idaho Earthquake of October 28, 1983—Strong Ground Motion

1985 ◽  
Vol 2 (1) ◽  
pp. 51-69 ◽  
Author(s):  
Suzette M. Jackson ◽  
John Boatwright
Keyword(s):  
Ground Motion ◽  
Main Shock ◽  
Near Field ◽  
Free Field ◽  
Ground Level ◽  
Shock Acceleration ◽  
Epicentral Area ◽  
Floor Level ◽  
Ground Floor ◽  
Vertical Accelerations

The 1983 Borah Peak, Idaho Earthquake was the largest normal faulting event to occur in the last 20 years. There were no near-field recordings of ground motion during the main shock, however, thirteen accelerographs in a permanent array at the Idaho National Engineering Laboratory (INEL) recorded the event at epicentral distances of 90-110 km. Peak horizontal accelerations, or PGA, recorded at accelerographs above ground-floor level range from 0.037 to 0.187 g. Accelerographs at basement and free-field sites recorded as low as 0.022 g and as high as 0.078 g. Peak vertical accelerations range from 0.016 g at ground level to 0.059 g above ground-floor level. A temporary array of digital seismographs deployed by the U. S. Geological Survey (USGS) in the epicentral area recorded ground motion from six large aftershocks at epicentral distances of 4-45 km; the largest of these aftershocks also triggered four accelerographs in the INEL array. This paper presents our estimates of near-field ground motion derived from two separate analyses. The first analysis uses the attenuation of the aftershock PGA measurements to extrapolate the INEL main shock PGA measurements into the near-field. This estimates an upper limit of 0.8 g for near-field ground motion. In the second analysis, a set of main shock accelerograms were synthesized. Wave propagation effects were determined from aftershock recordings at one of the USGS portable stations and an INEL seismograph station. These effects were removed from one of the INEL main shock acceleration traces. The synthetic accelerograms were derived for a hypothetical station southwest of Mackay, Idaho. The PGA measured from the synthetic accelerograms were 0.08, 0.14, 0.15, 0.23 g. These estimates correlate well with ground motion expected for an area of intensity VII.

scholarly journals Analysis of correlation between structural response and ground motion intensity measures.

2021 ◽  
Author(s):  
Tariq Anwar Aquib ◽  
Jayalakshmi Sivasubramonian ◽  
Paul Martin Mai
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Epicentral Distance ◽  
Ground Motions ◽  
Near Field ◽  
Plastic Hinge ◽  
Natural Period ◽  
Intensity Measures ◽  
Wide Range ◽  
Engineering Demand Parameters

<p>Loss estimation for buildings that experienced earthquake shaking is an important step in Performance Based Earthquake Engineering (PBEE), comprising four major components – seismic hazard, building response, probability of damage, and the costs incurred in losses and repair works. The implementation of PBEE strongly depends on the ability to predict Engineering Demand Parameters (EDPs) that are usually defined in terms of maximum story drifts, plastic hinge rotations, and floor accelerations.</p><p>In this study, we compute building responses for large sets of recorded ground motions considering frames with different natural periods (0.1-1.5s). The ground motion data used in our analysis comprise near field records from moderate-to-large earthquakes; these may generate shaking levels high enough to be of concern for the design and safety of buildings. We select the frames by varying the number of storys and bays to obtain a wide range of natural building periods. We compute ground motion intensity measures (IM) from the recorded dataset and extract engineering demand parameters (EDP) from building response analyses. Our results indicate that the inter-story drift correlates strongly with spectral measures of ground motion intensity (correlation coefficient above 0.85). We also investigate the effect of natural period on the estimated correlations. We find that the correlations with spectral intensity measures do not strongly depend on Vs30 and epicentral distance. Our results are useful in the context of applied performance-based design of structures, especially if uncertainties in seismological parameters due to limited knowledge of source, site or path effects play an important role in earthquake ground motions.</p>

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