Comparative analysis of a new assessment of the seismic risk of residential buildings of two districts of Barcelona

There are personal and institutional decisions that can increase the seismic resilience of the buildings in a city. However, some of these decisions are possible if we have basic knowledge of buildings’ seismic risk. The present document describes the main results of a detailed study of seismic vulnerability and seismic risk of residential buildings of Ciutat Vella (the ancient district of Barcelona) and Nou Barris (one of the newest districts of Barcelona). In this study, we assessed seismic risk according to the Vulnerability Index Method-Probabilistic named as VIM_P. Moreover, we analyzed the influence of basic buildings’ features in the final vulnerability and seismic risk values. For instance, we assessed the seismic vulnerability and the seismic risk of groups of buildings defined according to the number of stories of the buildings. Findings of this research reveal that the annual frequency of exceedance of the collapse damage state in Ciutat Vella buildings is, on average, 4.7 times higher than for the buildings in Nou Barris. Moreover, according to the Best vulnerability curve, 70.31% and 2.81% of Ciutat Vella and Nou Barris buildings, respectively, have an annual frequency of exceedance of the collapse damage state greater than 1 × 10–5.The present research has received partial funding from the European Union’s Horizon 2020 research 826 and innovation program (grant agreement Nº 823844, ChEESE CoE Project).Peer ReviewedPostprint (author's final draft

Evaluation of road network slopes susceptibility to seismically-induced landslides in the Granada Basin (S Spain)

In this work, a method for the fast evaluation of seismically-induced landslides is applied at regional scale in the Granada Basin (southern Spain). The methodology is based on the concept of rigid block but takes into account the variability in input data (geotechnical properties, failure depth and saturation state of the materials) through the use of a logical tree scheme. Input data were combined and evaluated using five different Newmark displacement empirical relations, which are automatically weighted to obtain a final co-seismic landslide susceptibility map. A Geographic Information System system was used to obtain the resulting maps considering the different branches and weights of the logic tree through an specifically developed automatic code written in Phyton. The landslides induced by the 2021 Mw 4.4 events of the Santa Fe seismic series have been used to validate the methodology. This is later used as input along with the road network to analyze the distribution of areas of different susceptibility level. The results obtained show that 1.73% of the total area is characterized by moderate to high susceptibility, being the southern and eastern sections of the Granada basin were more vulnerable slopes are found. When considering only zones around the road network (50m buffer), it is found that 2.11% of slopes around highways and 1.33% of road slopes have moderate to high susceptibility, especially the A-92 highway and the A-338 road. These roads traverse areas with steep slopes and a combination of hard and soft materials, which increases the susceptibility of disrupted landslides. On the other hand, in more densely populated areas such as the metropolitan area of Granada, the susceptibility is lower due to their location on terrain with low to negligible slopes. The results are of interest for authorities managing slope stabilities because they allow establishing effective and locally-based seismic forecast works in order to minimize the damage of future events.Projects PID 2021-124155NB-C31PID 2022-136678NB-I00 AEI/FEDER from the Spanish Investigation AgencyResearch group “Planetary Geodynamics, Active Tectonics and Related Hazards”, UCM-910368 of the Complutense University of Madrid.Institut Cartogràfic Valencia, by the Agency Valencian Security and Response to Emergencies (Generalitat Valenciana) and by the Provincial Consortium of Alicante FirefightersResearch VIGROB20-184 (University of Alicante

Compatibility of Seismic Hazard and Risk Calculations with Historical Observations

Diese Dissertation befasst sich mit der Bewertung der Modellierung der Erdbebengefährdung und der Schäden durch Vergleich mit historischen Erdbeben und Schadensinformationen. Ina Cecic, Präsidentin der European Seismological Commission, bemerkt dazu: „Ich freue mich zu bemerken, dass wir die Aktivitäten für interdisziplinäre Aufgaben immer weiter ausdehnen und über die „reine“ Seismologie hinaus auf andere Bereiche vordringen, die im wirklichen Leben miteinander verbunden sind. Dies ist besonders wichtig für die Bereiche Bildung und Öffentlichkeitsarbeit, da nur das Bewusstsein für die Gefahren in unserer Umgebung und das Wissen darüber, was zu tun ist, langfristig Leben retten kann.“ In dieser Arbeit wird zunächst ein systematischer Rahmen für die flächenbezogene Bewertung der Qualität der seismischen Gefahrenkarten entwickelt. Seit vielen Jahrzehnten ist die Erdbebengefährdunskarte in den meisten Ländern ein zwingender Bestandteil der Konstruktionspraxis. Anstrengungen zur Beurteilung der tatsächlichen Qualität dieser Karten sind essentiell. Unterschiedliche Metriken und Kriterien werden angewendet und detailliert diskutiert. Ich untersuche diese Frage am Beispiel des Einflußes der Magnituden-Häufigkeit. Zweitens wurden in den letzten vier Jahrzehnten zahlreiche Forschungsberichte und -dokumente veröffentlicht, die sich mit der Anfälligkeit von Gebäuden für Bodenbewegungen aufgrund von Erdbeben in China befassen, da eine umfassende Bewertung der seismischen Anfälligkeit von Gebäuden eine Schlüsselaufgabe der Erdbebensicherheits- und Schadensbewertung ist. Aus diesem Grund habe ich zuerst 69 Artikel und Dissertationen unter die Lupe genommen und untersuchte die Gebäudeschäden, die durch Erbeben in dicht besiedelten Gebieten entstanden sind. Sie stellen Beobachtungen dar, bei denen die makroseismischen Intensitäten gemäß der chinesischen offiziellen Seismic Intensity Scale bestimmt wurden. Aus diesen vielen Studien werden die mittleren Fragilitätsfunktionen (abhängig von der Makro-seismischen Intensität) für vier Schadensgrenzzustände von zwei am weitesten verbreiteten Gebäudetypen abgeleitet: Mauerwerk und Stahlbeton. Ich habe auch 18 Veröffentlichungen untersucht, die analytische Fragilitätsfunktionen (abhängig von der Spitzenbeschleunigung - PGA) für dieselben Schadensklassen und Gebäudekategorien bereitstellen. Auf diese Weise wird eine solide Fragilitätsdatenbank für seismisch gefährdete Gebiete auf dem chinesischen Festland erstellt, die sowohl auf Intensität als auch auf PGA basiert. Es wird ein umfassender Überblick über die Probleme bei der Bewertung der Fragilität für verschiedene Gebäudetypen gegeben. Ein notwendiger Vergleich mit internationalen Projekten mit ähnlichem Schwerpunkt wird durchgeführt. Basierend auf der neu gesammelten Fragilitätsdatenbank wird ein neuer Ansatz zur Ableitung der Intensität-PGA-Beziehung unter Verwendung der Fragilität als Brücke vorgeschlagen, und es werden optimierte Intensität-PGA-Beziehungen entwickelt. Dieser Ansatz führt zur Verringerung der Streuung in der traditionellen Intensitäts-PGA-Beziehung. Drittens, für die Risikoanalyse wird der Gebäudebestand, der durch ein Erdbeben gefährdet ist benötigt. Diese Studie entwickelt einen Ansatz einesgeo-kodierten Bestandsmodells für Wohngebäude für das chinesische Festland durch. Hierbei werden die Daten der Volkszählung in einem 1 km × 1 km Rahmen als Proxy benutzt. Zur Bewertung der Modellleistung wird die in diesem Kapitel entwickelte Wohnfläche auf Bezirksebene mit Aufzeichnungen aus dem statistischen Jahrbuch verglichen. Es zeigt sich, dass die in dieser Studie entwickelte Grundfläche nach Bereinigung um einheitliche Baukosten durchaus mit der Grundflächenstatistik von Shanghai vergleichbar ist. Die Anwendung dieses Modells in der Risikoanalyse des Erdbebens in Wenchuan M8.0 wird ebenfalls durchgeführt. Der auf der Grundlage dieses Expositionsmodells für Wohngebäude geschätzte Gesamtverlust entspricht in etwa dem Verlustwert, der aus Schadensmeldungen auf der Grundlage von Felduntersuchungen abgeleitet wurde. Diese Kongruenzen verdeutlichen die Robustheit des hier entwickelten Wohnungsbestandmodells. Schließlich wird die Schadensabschätzung mithilfe verschiedener Methoden durchgeführt und ein Vergleich mit Schäden angestellt, die aus Schadensmeldungen abgeleitet wurden. Zur Verbesserung des Verlustverteilungsmusters wird die Entwicklung eines regionalen Human Development Indexes vorgeschlagen. Sensitivitätstests werden durchgeführt, um die Auswirkungen jedes Faktors auf die Ermittlung des endgültigen Verlusts zu überprüfen

VALIDATING THE CANADIAN SEISMIC RISK MODEL

openCanada faces a scarcity of impactful earthquakes that can be used to validate seismic risk models, as the last significant damaging earthquakes occurred in the 1980s (Hobbs, Journeay, and Rotheram 2021). To overcome this limitation, this study aims to assess the reliability of the Canadian National Seismic Risk Model (CanadaSRM1) by analyzing the shaking intensities and physical impacts recorded from several recent events. These events include the 2010 Mw 5.5 Val-des-Bois and 2013 Mw 4.6 Ladysmith earthquakes in Eastern Canada, the 1985 M 6.9 Nahanni earthquake in Northern Canada, and the 2017 Mw 6.2 - 6.3 Mosquito Lake pair earthquakes in Western Canada. By evaluating the potential consequences of mentioned earthquakes in south-western Quebec, the Northwest Territories, and southern Yukon (near Whitehorse), the study aims to assess the potential impact on densely settled metropolitan areas across the country. In order to support disaster risk reduction efforts and advance the objectives of the Sendai Framework for Disaster Risk Reduction, Natural Resources Canada (NRCan) partnered with Global Earthquake Model Foundation, Italy (GEM) to develop a public Canadian Seismic Risk Model (Hobbs et al. 2023). This collaborative effort involved creating a national exposure inventory, Canadian-specific fragility and vulnerability curves, and adjusting the Canadian Seismic Hazard Model, which is the basis for the seismic provisions in the National Building Code of Canada. The risk modeling process, using GEM's OpenQuake-Engine (OQ), utilizes deterministic and probabilistic calculations to assess seismic risk at the neighborhood level for all Dissemination Areas (DAUID) in Canada. By considering baseline and simulated retrofit conditions, the model provides risk metrics such as expected immediate physical impacts, including building damage, casualties, and direct economic losses. This approach of Seismic Risk Assessment (SRA) relies on previous earthquake knowledge to estimate the potential consequences of future earthquakes, enabling the evaluation of proposed mitigation and adaptation measures for disaster risk reduction. This thesis presents a comprehensive analysis of the potential damage caused by benchmark scenario earthquakes, including shaking damage to buildings, financial losses, fatalities, and other impacts. The study utilizes the OQ Engine and the national exposure dataset, following the methodology of the CanadaSRM1. The primary findings, such as damage distributions, loss exceedance curves, and annual average losses, offer an accessible and quantifiable foundation of evidence for decision-making at various levels - local, regional, and national. These results demonstrate a high degree of consistency with observed or predicted impacts, taking into account economic and population growth adjustments. Consequently, this confirms the reliability of the first generation Canadian Seismic Risk Model, aligning it with industry standards and enabling the reproduction of recent destructive earthquakes. Given Canada's vast size, intricate seismic hazard model, and dispersed populations, this study holds unique significance. Nonetheless, the challenges faced, and solutions provided are likely to be valuable to other countries undertaking similar programs

An integrated computational approach for seismic risk assessment of individual buildings

The simultaneous assessment of a great number of buildings subjected to different ground motions is a very challenging task. For this reason, a new computational integrated approach for seismic assessment of individual buildings is presented, which consists of several independent computer objects, each having its own user interface, yet being totally interconnectable like in a puzzle. The hazard module allows considering a code-based response spectrum or a predicted response spectrum for a given earthquake scenario, which is computed throughout the resolution of an optimization problem. The vulnerability of each building is assessed based on structural capacity curves. Damage is evaluated using an innovative proposal, which is to use what was called a performance curve associated with a capacity curve. This curve reproduces the percentage of a given response spectrum corresponding to a performance point for each displacement value of a capacity curve. Therefore, it becomes possible to do a very fast association of any limit state to a percentage of a seismic action. This approach was implemented in the PERSISTAH software, and the result outputs can be exported, instantaneously, to the Google Earth software throughout the creation of a kml file, or to MS Excel.This research was funded by INTERREG-POCTEP España-Portugal program and the European Regional Development Fund, grant number 0313_PERSISTAH_5_P.info:eu-repo/semantics/publishedVersio

New Perspectives in the Definition/Evaluation of Seismic Hazard through Analysis of the Environmental Effects Induced by Earthquakes

The devastating effects caused by the recent catastrophic earthquakes that took place all over the world from Japan, New Zealand, to Chile, as well as those occurring in the Mediterranean basin, have once again shown that ground motion, although a serious source of direct damage, is not the only parameter to be considered, with most damage being the result of coseismic geological effects that are directly connected to the earthquake source or caused by ground shaking. The primary environmental effects induced by earthquakes as well as the secondary effects (sensu Environmental Seismic Intensity - ESI 2007 scale) must be considered for a more correct and complete evaluation of seismic hazards, at both regional and local scales. This Special Issue aims to collect all contributions that, using different methodologies, integrate new data produced with multi-disciplinary and innovative methods. These methodologies are essential for the identification and characterization of seismically active areas, and for the development of new hazard models, obtained using different survey techniques. The topic attracted a lot of interest, 19 peer-reviewed articles were collected; moreover, different areas of the world have been analyzed through these methodologies: Italy, USA, Spain, Australia, Ecuador, Guatemala, South Korea, Kyrgyzstan, Mongolia, Russia, China, Japan, and Nepal