Browsing by Author "Mitrani-Reiser, Judith"

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    Data collection after the 2010 Maule earthquake in Chile.
    (2017) Llera Martin, Juan Carlos de la; Santa María Oyanedel, Hernán; Rivera, Felipe; Mitrani-Reiser, Judith; Jünemann Ureta, Rosita; Fortuno, Catalina; Ríos, Miguel; Hube Ginestar, Matías Andrés; Cienfuegos Carrasco, Rodrigo Alberto
    This article presents an overview of the different processes of data recollection and the analysis that took place during and after the emergency caused by the Mw 8.8 2010 Maule earthquake in central-south Chile. The article is not an exhaustive recollection of all of the processes and methodologies used; it rather points out some of the critical processes that took place with special emphasis in the earthquake characterization and building data. Although there are strong similarities in all of the different data recollection processes after the earthquake, the evidence shows that a rather disaggregate approach was used by the different stakeholders. Moreover, no common standards were implemented or used, and the resulting granularity and accuracy of the data was not comparable even for similar structures, which sometimes led to inadequate decisions. More centralized efforts were observed in resolving the emergency situations and getting the country back to normal operation, but the reconstruction process took different independent routes depending on several external factors and attitudes of individuals and communities. Several conclusions are presented that are lessons derived from this experience in dealing with a large amount of earthquake data. The most important being the true and immediate necessity of making all critical earthquake information available to anyone who seeks to study such data for a better understanding of the earthquake and its consequences. By looking at the information provided by all these data, we aim to finally improve seismic codes and engineering practice, which are important social goods.
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    Earthquake risk assessment of buildings accounting for human evacuation
    (2017) Poulos Campbell, Alan John; Llera Martin, Juan Carlos de la; Mitrani-Reiser, Judith
    A primary goal of earthquake engineering is to protect society from the possible negative consequences of future earthquakes. Conventionally, this goal has been achieved indirectly by reducing seismic damage of the built environment through better building codes, or more comprehensibly, by minimizing seismic risk. However, the effect that building damage has on occupants is not explicitly taken into account while designing infrastructure. Consequently, this paper introduces a conceptual framework and numerical algorithm to assess earthquake risk on building occupants during seismic events, considering the evacuation process of the structure. The framework combines probabilistic seismic hazard analysis, inelastic structural response analysis and damage assessment, and couples these results with the response of evacuating agents. The results are cast as probability distributions of variables that measure the overall performance of the system (e.g., evacuation times, number of injured people, and repair costs) for specific time windows. As a testbed, the framework was applied to the response of a reinforced concrete frame building that exemplifies the use of all steps of the methodology. The results suggest that this seismic risk evaluation framework of structural systems that combine the response of a physical model with human agents can be extended to a wide variety of other situations, including the assessment of mitigation actions in communities and people to improve their earthquake resilience. Copyright © 2016 John Wiley & Sons, Ltd.
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    Healthcare network’s response and resilience in Iquique after the 2014, Pisagua earthquake
    (National Information Centre of Earthquake Engineering, 2017) Vásquez, Andrea; Rivera Jofré, Felipe Andrés; Llera Martin, Juan Carlos de la; Mitrani-Reiser, Judith
    On April 1st, 2014, the 8.2 Mw Pisagua earthquake affected the population in the north of Chile and generated disruption of services in the region. The largest effects of the earthquake were observed in the city of Iquique, capital of the Tarapaca Region, where more than 80% of the population of the region lives. This research describes the response of the public healthcare network of Iquique after the earthquake, and aims to identify the principal factors contributing to the network resilience during the early response and recovery phase after the earthquake. Despite the large magnitude of the earthquake, the observed structural damage was minor in the five healthcare centers considered (i.e., the regional hospital and 4 Primary Healthcare Attention Centers, PHACs). However, disruption of services in the healthcare network was large and due mainly to the collapse of non-structural components. Overall, the proper response of the healthcare network of Iquique was heavily supported by the PHACs, which largely provided first-aid, containment, and low-complexity attention to the population, allowing the hospital to focus on more complex procedures. The findings of this study suggest that the resilience of the healthcare network system, besides the robustness of the network’s facilities and their critical units, is also highly dependent on the interrelations and interactions between them in early post-earthquake recovery phases.
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    Impact on chilean hospitals following the 2015 Illapel earthquake
    (National Information Centre of Earthquake Engineering, 2017) Favier, Philomène; Rivera Jofré, Felipe Andrés; Poulos Campbell, Alan John; Vásquez P., Jorge; Llera Martin, Juan Carlos de la; Mitrani-Reiser, Judith
    In a post-disaster environment, hospitals play a critical role in healthcare services continuities to the population while effectively coping with eventual losses of functionality. These losses come from physical damage to the facility, loss of utility lifelines, failure in supply chains, and reduction of personnel. However, data describing the detailed performance of hospitals during past earthquakes are scarce. Consequently, following the 2015 Mw 8.3 Illapel earthquake in central Chile, an exhaustive field campaign was carried out in the Coquimbo region to collect substantial perishable data to describe physical damage to hospitals and functionality losses. This study presents first the baseline information obtained in nine surveyed government hospitals, including size, location and type of infrastructure. Then, the seismic impact was analyzed and classified to show the main physical structural and non-structural damage, lifeline interruptions, losses in hospital units, and variations in flow of patients and staff. Transfers, discharges and evacuations of patients that occurred after the event were also reported. We found that the earthquake did not affect strongly the healthcare service despite the fact that most of the structural and non-structural damage was localized in the largest regional hospital. The archival nature of the data collected may deepen our understanding of the post-earthquake healthcare system performance, which is very useful in improving disaster preparation and overall resilience.
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    Seismic risk assessment of human evacuations in buildings
    (National Information Centre of Earthquake Engineering, 2017) Poulos Campbell, Alan John; Castro Hernández, Sebastián Andrés; Llera Martin, Juan Carlos de la; Mitrani-Reiser, Judith
    Major earthquakes may require people to evacuate immediately from buildings as recently observed in the 2015 Mw 8.3 Illapel earthquake in Chile. The building may suffer damage, thus affecting the evacuation process. Perhaps due to its apparent complexity, this interaction has not been taken into account when computing seismic risk variables that are intrinsically coupled, such as evacuation times and number of injured people. This limitation can be addressed by simulating the evacuation processes and the physical damage together using agent-based modelling. The evacuation of the building emerges from a set of rules that govern the interaction between agents and with their (damaged) physical surrounding. This research focuses first on modeling evacuations when no physical damage occurs, and uses real evacuation drills performed in a K-12 school and an office building as validation. The comparison was carried out under a low level of uncertainty in the initial conditions of the occupants, i.e., their initial positions and pre-evacuation times were relatively well known, resulting in prediction errors in total evacuation time of only 5.9% and 5.7% for the school and office building, respectively. The evacuation model is then extended to consider building damage and used in an integrated methodology to evaluate the seismic risk of building occupants. This assessment was divided into five steps: (i) seismic hazard, (ii) structural response, (iii) building damage, (iv) evacuation, and (v) risk assessment. First, probabilistic seismic hazard analysis was used to compute the frequency of different levels of local earthquake intensity, characterized herein by the spectral acceleration at the fundamental period of the structure. Ground motions accelerograms matching these intensities were then used in dynamic analyses of the inelastic structure to compute the building response. Story drifts and floor accelerations of the building were related to the damage of non-structural components (e.g., ceilings and partition walls) using appropriate fragility curves. The estimated damage state of the building was used to feed an agent-based evacuation model and assess the evacuation response of the building occupants in this new environment. The outputs of the model are probability distributions of different performance measures and losses, such as evacuation times and number of injured people. These results can better inform decision making processes to mitigate the consequences that future earthquakes will have on buildings and their inhabitants, as well as provide useful information in modeling other larger scale city evacuation scenarios.
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    The 2010 Chile Earthquake: a five-year reflection
    (Australian Earthquake Engineering Society, 2015) Llera Martin, Juan Carlos de la; Mitrani-Reiser, Judith; Rivera Jofré, Felipe Andrés; Fortuño, C.; Jünemann Ureta, Rosita; Poulos Campbell, Alan John; Vásquez P., Jorge
    At 3:34AM local time, on February 27th, 2010, a moment magnitude Mw 8.8 megathrust earthquake struck offshore the coast of Chile. The earthquake ruptured a 540 by 200 km mature seismic gap of the underlying subduction pacific plate interlocking mechanism. More than 75% of the 16 million Chileans spread over several large urban areas in the center-south of the country were affected by the earthquake, which caused 521 fatalities with 124 of them due to the tsunami, and an overall damage estimate of USD 30 billion. Because the earthquake struck the most densely populated area of the country, it represents a very unique opportunity to reflect on its ubiquitous impact over many different physical and social systems. The reflection contained in this article occurs five years later, once reconstruction and recovery are complete from this longitudinal wound of the country. Seismic codes have changed, research on the supposedly indestructible reinforced concrete shear walls has been done, new seismic protection technologies have been incorporated, and whole new seismic standards have been adopted by communities and people. The price it took was quite high, but we can confidently say that Chile is better prepared today for the next large earthquake.
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    Validation of an agent-based building evacuation model with a school drill
    (2018) Poulos Campbell, Alan John; Tocornal, Felipe; Llera Martin, Juan Carlos de la; Mitrani-Reiser, Judith
    An effective evacuation of buildings is critical to minimize casualties due to natural or anthropogenic hazards. Building evacuation models help in preparing for future events and shed light on possible shortcomings of current evacuation designs. However, such models are seldom compared or validated with real evacuations, which is a critical step in assessing their predictive capacities. This research focuses on the evacuation of a K-12 (kindergarten to 12th grade) school located within the tsunami inundation zone of Iquique, Chile. An agent-based evacuation model was developed to simulate the evacuation of approximately 1500 children and staff from the school during a global evacuation drill carried out for the entire city. The model simulates the motions of heterogeneous human agents, and the simulations were validated using video analysis of the real event. Resulting error estimations between predicted versus measured flow rates and evacuation times are 13.5% and 5.9%, respectively. The good agreement between the simulated and measured values can be attributed to the known distribution of students and staff at the start of the drill, and their known exposure to emergency preparedness protocols. However, the results presented herein show that this mathematical evacuation model can be used for logistical changes in the emergency planning.