Assessment of earthquake damage considering the characteristics of past events in South America

Earthq Engng Struct Dyn

Horspool

2019

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Funding informationThe Global Earthquake Model and the RiskScape project. SummaryThe evaluation of the potential impact of strong seismic events shortly after their occurrence is a critical step to organise emergency response and consequently minimise the adverse effects of earthquakes. The estimation of the impact from earthquakes considering the observed ground shaking from past events can be useful for the calibration of existing exposure and/or fragility and vulnerability models. This study describes a methodology to combine the publicly available information from the USGS ShakeMap system and the open-source software OpenQuake engine for the assessment of damage and losses. This approach is employed to estimate the number of structural collapses considering the 2012 Magnitude 5.9 Emilia-Romagna (Italy) earthquake and the aggregated economic loss because of the 2010 Magnitude 7.1 Darfield (New Zealand) event. Several techniques to calculate the ground shaking in the affected region considering the spatial and interperiod correlations in the intra-event ground motion residuals are investigated and their influence in the resulting damage or loss estimates are evaluated.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Combining USGS ShakeMaps and the OpenQuake‐engine for damage and loss assessment

Earthq Engng Struct Dyn

Horspool

2019

Self Cite

“…This is done taking into account the aleatory and epistemic uncertainty in both the vulnerability and the ground shaking components. For each realization of IM random field for a given earthquake, the fragility curve for complete damage (i.e., structure beyond repair, but not necessarily collapsed; e.g., Villar-Vega & Silva 30 ) for a given building at a given location is used to simulate, using a random sampling process, whether the building may or may not collapse. For any given earthquake-specific ground motion field, this calculation is repeated for all the buildings in the area to obtain a possible realization of the locations of collapsed structures.…”

Section: Seismic Demand and Estimation Of Damagementioning

confidence: 99%

Application of open tools and datasets to probabilistic modeling of road traffic disruptions due to earthquake damage

Costa

Figueiredo

Earthq Engng Struct Dyn

et al. 2020

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Summary The disruption of a transportation network can have a high social and economic impact on the welfare of a society, as it can significantly affect the daily routines of a community. Although many studies have focused on the estimation of physical risk in the components that compose these networks, only a limited number have analyzed their interconnections and impact in the traffic flow. The present study analyzes how earthquake damage can disrupt the road network in an urban environment, and how this will influence the ability of the population to travel. Traffic due to daily commutes is modeled for different layouts of the network, corresponding to possible disruptions caused by earthquake damage. The duration and length of each trip were calculated both for the undamaged network conditions and for the disrupted network. The increase in the median duration and length of each trip allows estimating the economic loss for each event due to drivers' delay. By combining the probability of a specific road being blocked with its number of users, the average number of affected vehicles was estimated, and the most critical segments identified. The methodology was applied to a case study concerning the road network of the area around the Italian city of Messina in Sicily. The results were calculated for both a repetition of the well‐known historical event of 1908 and a set of simulated earthquakes consistent with the national probabilistic seismic hazard model of Italy.

“…collapse). In this paper, we focus our scenario analysis on the spatial distribution of collapsed buildings, which comprises not only physically collapsed buildings but also partially collapsed structures (Villar-Vega et al, 2017).…”

Section: Building Fragility and Vulnerability Modelsmentioning

confidence: 99%

Contrasting seismic risk for Santiago, Chile, from near-field and distant earthquake sources

Hussain

Elliott

Nat. Hazards Earth Syst. Sci.

et al. 2020

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Abstract. More than half of all the people in the world now live in dense urban centres. The rapid expansion of cities, particularly in low-income nations, has enabled the economic and social development of millions of people. However, many of these cities are located near active tectonic faults that have not produced an earthquake in recent memory, raising the risk of losing hard-earned progress through a devastating earthquake. In this paper we explore the possible impact that earthquakes can have on the city of Santiago in Chile from various potential near-field and distant earthquake sources. We use high-resolution stereo satellite imagery and imagery-derived digital elevation models to accurately map the trace of the San Ramón Fault, a recently recognised active fault located along the eastern margins of the city. We use scenario-based seismic-risk analysis to compare and contrast the estimated damage and losses to the city from several potential earthquake sources and one past event, comprising (i) rupture of the San Ramón Fault, (ii) a hypothesised buried shallow fault beneath the centre of the city, (iii) a deep intra-slab fault, and (iv) the 2010 Mw 8.8 Maule earthquake. We find that there is a strong magnitude–distance trade-off in terms of damage and losses to the city, with smaller magnitude earthquakes in the magnitude range of 6–7.5 on more local faults producing 9 to 17 times more damage to the city and estimated fatalities compared to the great magnitude 8+ earthquakes located offshore in the subduction zone. Our calculations for this part of Chile show that unreinforced-masonry structures are the most vulnerable to these types of earthquake shaking. We identify particularly vulnerable districts, such as Ñuñoa, Santiago, and Providencia, where targeted retrofitting campaigns would be most effective at reducing potential economic and human losses. Due to the potency of near-field earthquake sources demonstrated here, our work highlights the importance of also identifying and considering proximal minor active faults for cities in seismic zones globally in addition to the more major and distant large fault zones that are typically focussed on in the assessment of hazard.