Earthquake-prone Cities Research Articles

The Influence of Urban Morphology on the Resilience of Cities Following an Earthquake

This paper proposes a conceptual theory of resilience in urbanism and demonstrates its application through a case study. The theory's underpinnings are the attributes of resilience that have been developed in ecological sciences, but have clear parallels in urbanism. They suggest that it may be possible to enhance the resilience of a city through the design of its urban morphology. The paper explores these ideas by examining the relationship between the community's adaptive behaviour and the spaces of the city of Concepción after its 2010 earthquake. This empirical evidence suggests that the role of the urban designer in earthquake-prone cities is perhaps more critical before an earthquake happens and that the more the idea of a resilient urban morphology is embedded as part of daily life, the more effective it is likely to be in the aftermath of a major earthquake.

Challenges to successful seismic retrofit implementation: a socio-behavioural perspective

Seismic retrofit implementation has been a major challenge in many earthquake-prone cities. This paper examines why building owners are reluctant to adopt measures to reduce earthquake losses despite advancement in seismic design methods and the enactment of intervening legislative frameworks. A case study approach revealed the socio-behavioural barriers affecting seismic retrofit implementation. Significant barriers identified included the perception of earthquake risks, a lack of trust in seismic strengthening techniques and a lack of support for pro-social mitigation behaviours from public authorities. The findings suggest that a reappraisal of the policy implementation approach used by government agencies is required, and that greater attention should be given to seismic designs recommended by professionals and approved by regulatory authorities in order to earn building owners' trust regarding the efficacy of earthquake risk-reduction measures. La mise aux normes parasismiques des constructions existantes est un défi majeur dans de nombreuses villes sujettes aux tremblements de terre. Le présent article examine pourquoi les propriétaires d'immeubles sont peu disposés à adopter des mesures permettant de réduire les sinistres dus aux tremblements de terre en dépit des progrès réalisés dans les méthodes de conception parasismique et malgré la promulgation de cadres législatifs d'intervention. Une approche par étude de cas a mis en évidence les barrières sociocomportementales affectant la mise en œuvre des normes parasismiques dans les immeubles existants. Ont été identifiés parmi ces obstacles importants la perception des risques de tremblements de terre, un manque de confiance dans les techniques de renforcement parasismique et un manque de soutien de la part des autorités publiques en faveur de comportements pro-sociaux permettant d'adoucir ces politiques. Les résultats obtenus suggèrent qu'il est nécessaire d'opérer une réévaluation de l'approche utilisée par les organismes publics pour mettre en œuvre ces politiques, et qu'il devrait être porté une plus grande attention aux conceptions parasismiques recommandées par les professionnels et homologuées par les organismes de réglementation de façon à gagner la confiance des propriétaires d'immeubles, s'agissant de l'efficacité des mesures de réduction des risques liés aux tremblements de terre. Mots clés: propriétaires d'immeubles, prise de décision, immeubles sujets aux tremblements de terre, politique publique, perception des risques, mise aux normes parasismiques, comportement des parties prenantes

VULNERABILITY OF WASTEWATER TREATMENT PLANTS AND WASTEWATER PUMPING STATIONS TO EARTHQUAKES

Earthquakes are the most common natural hazard in New Zealand which can affect lifelines in populated areas. This research takes into account earthquake effects on treatment plants and pumping stations in wastewater systems as a lifeline. Wastewater treatment plants in four earthquake prone areas in New Zealand were selected for the purpose of assessing their vulnerabilities to earthquakes. Results showed that simple upgraded wastewater treatment plants are the most vulnerable type of wastewater treatment plants in New Zealand. Earthquake vulnerability of 45 wastewater pumping stations in 3 earthquake prone cities in New Zealand was also assessed. The assessment proved that non‐structural components are among the most vulnerable parts in wastewater pumping stations. Since structural vulnerability of some wastewater pumping stations is notable, it requires a need for an immediate rehabilitation plan. Santruka Naujojoje Zelandijoje žemes drebejimai yra labiausiai tiketina stichine nelaime, apgyvendintose teritorijose galinti paveikti gyvybiškai svarbius tinklus. Šiame tyrime nagrinejamas žemes drebejimu poveikis nuoteku tinkluose veikiančioms valymo ir pumpavimo stotims, kurios yra gyvybiškai svarbios. Siekiant ivertinti, kaip žemes drebejimai gali pažeisti nuoteku valymo stotis, buvo pasirinktos valymo stotys iš keturiu seismiškai aktyviu Naujosios Zelandijos zonu. Rezultatai parode, kad Naujojoje Zelandijoje labiausiai pažeidžiamos paprastos atnaujintos nuoteku valymo stotys. Ivertintas ir trijuose seismiškai aktyviuose Naujosios Zelandijos miestuose esančiu 45 nuoteku pumpavimo stočiu pažeidžiamumas per žemes drebejimus. Ivertinus nustatyta, kad nuoteku pumpavimo stotyse labiausiai pažeidžiami yra nestruktūriniai elementai. Kadangi kai kuriose nuoteku pumpavimo stotyse struktūru pažeidžiamumas yra didelis, reikia nedelsiant sudaryti rekonstrukcijos plana.

Earthquake-Prone Cities

Earthquake-Prone Cities

Broadband frequency-dependent amplification of seismic waves across Bucharest, Romania

The determination of seismic amplitude amplification is a fundamental contribution to seismic hazard assessment. While often only high-frequency amplitude variations (>1 Hz) are taken into account, we analyse broadband waveforms from 0.14 to 8.6 Hz using a temporary network of 32 stations in and around the earthquake-prone city of Bucharest. Spectral amplitudes are calculated with an adaptive multiple-taper approach. Across our network (aperture 25 km × 25 km), we find a systematic northwest/southeast-oriented structural influence on teleseismic P-wave amplitudes from 0.14 to 0.86 Hz that can be explained by constructive interference in the dipping Cenozoic sedimentary layers. For higher frequencies (1.4–8.75 Hz), more local site effects prevail and can be correlated partly among neighbouring stations. The transition between systematic and localised amplitude variations occurs at about 1 Hz.

A CRITICAL REVIEW OF THE SEISMIC HAZARD ZONING OF PESHAWAR AND ADJOINING AREAS

Many of the structural engineers in Pakistan refer to the UBC code for the design of aseismic structures. On the seismic zones of international cities, the UBC code 1997 has placed Peshawar in the most severe earthquake Zone 4 similar to the high earthquake prone cities of California, Alaska, Japan, Chile, Taiwan or Turkey. These places have suffered some of the most destructive earthquakes of the past. The earthquake history of Peshawar, however, does not inform us about moderate devastation. Moreover work done on the seismic zoning of Pakistan by different national and international agencies and independent researchers present widely conflicting pictures of the seismic hazard of Peshawar. This paper critically reviews almost all of the published work done on seismic zoning, in the light of the locally available data, geology, tectonics and earthquake history of Peshawar.

Simulation of seismic response in a city-like environment

We study the seismic response of idealized 2D cities, constituted by non-equally spaced, non-equally sized homogenized blocks anchored in a soft layer overlying a hard half space. The blocks and soft layer are occupied by dissipative media. To simulate such response, we use an approximation of the viscoelastic modulus by a low-order rational function of frequency and incorporate this approximation into a first-order-in-time scheme. Our results display spatially variable, strong, long-duration responses inside the blocks and on the ground, which qualitatively match the responses observed in some earthquake-prone cities of Mexico, France, the USA, etc.

Simulation of seismic response in an idealized city

We study the seismic response of an idealized 2D ‘city’, constituted by ten non equally-spaced, non equally-sized, homogenized blocks (i.e. buildings or groups of buildings) anchored in a soft soil layer overlying a hard halfspace. Our results display strong response inside the blocks and on the ground which qualitatively match the responses observed in some earthquake-prone cities.