scholarly journals Seismic Vulnerability Assessment and Mapping of Gyeongju, South Korea Using Frequency Ratio, Decision Tree, and Random Forest

2020 ◽  
Vol 12 (18) ◽  
pp. 7787 ◽  
Author(s):  
Jihye Han ◽  
Jinsoo Kim ◽  
Soyoung Park ◽  
Sanghun Son ◽  
Minji Ryu
Keyword(s):  
Random Forest ◽  
Decision Tree ◽  
South Korea ◽  
Vulnerability Assessment ◽  
Seismic Data ◽  
Frequency Ratio ◽  
Seismic Vulnerability ◽  
Success Rates ◽  
Ground Acceleration ◽  
Seismic Vulnerability Assessment

The main purpose of this study was to compare the prediction accuracies of various seismic vulnerability assessment and mapping methods. We applied the frequency ratio (FR), decision tree (DT), and random forest (RF) methods to seismic data for Gyeongju, South Korea. A magnitude 5.8 earthquake occurred in Gyeongju on 12 September 2016. Buildings damaged during the earthquake were used as dependent variables, and 18 sub-indicators related to seismic vulnerability were used as independent variables. Seismic data were used to construct a model for each method, and the models’ results and prediction accuracies were validated using receiver operating characteristic (ROC) curves. The success rates of the FR, DT, and RF models were 0.661, 0.899, and 1.000, and their prediction rates were 0.655, 0.851, and 0.949, respectively. The importance of each indicator was determined, and the peak ground acceleration (PGA) and distance to epicenter were found to have the greatest impact on seismic vulnerability in the DT and RF models. The constructed models were applied to all buildings in Gyeongju to derive prediction values, which were then normalized to between 0 and 1, and then divided into five classes at equal intervals to create seismic vulnerability maps. An analysis of the class distribution of building damage in each of the 23 administrative districts showed that district 15 (Wolseong) was the most vulnerable area and districts 2 (Gangdong), 18 (Yangbuk), and 23 (Yangnam) were the safest areas.

scholarly journals Performance of Logistic Regression and Support Vector Machines for Seismic Vulnerability Assessment and Mapping: A Case Study of the 12 September 2016 ML5.8 Gyeongju Earthquake, South Korea

2019 ◽  
Vol 11 (24) ◽  
pp. 7038 ◽  
Author(s):  
Jihye Han ◽  
Soyoung Park ◽  
Seongheon Kim ◽  
Sanghun Son ◽  
Seonghyeok Lee ◽  
...  
Keyword(s):  
Logistic Regression ◽  
South Korea ◽  
Vulnerability Assessment ◽  
Seismic Vulnerability ◽  
Spatial Databases ◽  
Support Vector ◽  
Seismic Vulnerability Assessment ◽  
The Common ◽  
Gyeongju Earthquake

In this study, we performed seismic vulnerability assessment and mapping of the ML5.8 Gyeongju Earthquake in Gyeongju, South Korea, as a case study. We applied logistic regression (LR) and four kernel models based on the support vector machine (SVM) learning method to derive suitable models for assessing seismic vulnerabilities; the results of each model were then mapped and evaluated. Dependent variables were quantified using buildings damaged in the 9.12 Gyeongju Earthquake, and independent variables were constructed and used as spatial databases by selecting 15 sub-indicators related to earthquakes. Success and prediction rates were calculated using receiver operating characteristic (ROC) curves. The success rates of the models (LR, SVM models based on linear, polynomial, radial basis function, and sigmoid kernels) were 0.652, 0.649, 0.842, 0.998, and 0.630, respectively, and the prediction rates were 0.714, 0.651, 0.804, 0.919, and 0.629, respectively. Among the five models, RBF-SVM showed the highest performance. Seismic vulnerability maps were created for each of the five models and were graded as safe, low, moderate, high, or very high. Finally, we examined the distribution of building classes among the 23 administrative districts of Gyeongju. The common vulnerable regions among all five maps were Jungbu-dong and Hwangnam-dong, and the common safe region among all five maps was Gangdong-myeon.

Large-Scale Seismic Vulnerability Assessment Method for Urban Centres. An Application to the City of Florence

2014 ◽  
Vol 628 ◽  
pp. 49-54 ◽  
Author(s):  
Maurizio Ripepe ◽  
Giorgio Lacanna ◽  
Pauline Deguy ◽  
Mario de Stefano ◽  
Valentina Mariani ◽  
...  
Keyword(s):  
Vulnerability Assessment ◽  
Large Scale ◽  
Seismic Vulnerability ◽  
Risk Mitigation ◽  
Structural Features ◽  
Assessment Method ◽  
Ground Acceleration ◽  
Seismic Vulnerability Assessment ◽  
Damage Scenarios ◽  
The City

The seismic vulnerability assessment of a building requires a comprehensive knowledge of both building structural features and soils geophysical parameters. To achieve a vulnerability assessment at the urban scale a large amount of data would be necessary, with a consequent involvement of time and economical resources. The aim of this paper is hence to propose a simplified procedure to evaluate the seismic vulnerability of urban centres and possible seismic damage scenarios in order to identify critical areas and/or building typologies to plan future actions of seismic risk mitigation and prevention. The procedure is applied to the outstanding case study of the city of Florence. The research is based on the definition of major building typologies related to construction periods and type of the structural system (masonry or reinforced concrete), the identification of a set of sample buildings, the analysis of the dynamic behaviour and the evaluation of a vulnerability index with an expeditious approach. The obtained results allow to define potential vulnerability and post-event damage scenarios related to the expected levels of peak ground acceleration.

scholarly journals Seismic vulnerability assessment of a high-rise molten-salt solar tower based on incremental dynamic analysis

2020 ◽  
Vol 194 ◽  
pp. 01005
Author(s):  
Weiwei Sun ◽  
Dina D’Ayala ◽  
Jinxing Fu ◽  
Wentao Gu ◽  
Jun Feng
Keyword(s):  
Dynamic Analysis ◽  
Molten Salt ◽  
Seismic Performance ◽  
Vulnerability Assessment ◽  
Seismic Vulnerability ◽  
Incremental Dynamic Analysis ◽  
Seismic Excitations ◽  
Ground Acceleration ◽  
Seismic Vulnerability Assessment ◽  
High Rise

This paper investigates the seismic performance of a high-rise molten-salt solar tower by finite element modelling. The integrated and separated models for solar tower based on the concrete damage plastic model are validated by matching the behaviour of similar reinforced concrete chimney specimens. The modal analysis demonstrates the first four modes of the solar tower are translational vibration. Seismic simulations are developed through the incremental dynamic analysis. The most disadvantageous position of the tower is all concentrated in the opening section under multidirectional seismic excitations. The top displacement of the tower under bidirectional and three-directional earthquake actions is larger than that under unidirectional earthquake actions. The results of the seismic vulnerability assessment show that when the PGA equals to 0.035g, the tower will be intact; when the PGA equals to 0.1g (design peak ground acceleration), the probability of the moderate damage state is within 1.5%; when the PGA equals to 0.22g (maximum considered earthquake), the probability of the destruction state is below 0.7%. The seismic partitioned fragility analysis of the tower under multidirectional earthquake excitations illustrates that there are two peaks in the vulnerability surfaces. The anti-collapse analysis indicates the tower has a good seismic performance under multidirectional seismic excitations.

scholarly journals Seismic Vulnerability Assessment of a Reinforced Concrete Building Located in India

2019 ◽  
Vol 8 (11S) ◽  
pp. 310-314
Keyword(s):  
Vulnerability Assessment ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Equivalent Linearization ◽  
Spectral Acceleration ◽  
Damage State ◽  
Ground Acceleration ◽  
Seismic Vulnerability Assessment ◽  
Performance Point ◽  
Damage States

Over the recent years the natural disaster especially due to the earthquake effect on buildings increases which causes loss of life and property in many places all over the world. The latest development leads to finding the direct losses and damage states of the buildings for various intensities of earthquake ground motions. In the present study, seismic vulnerability assessment was done for a medium rise building (G+5). The design peak ground acceleration of 0.16g and 0.36g were considered for the risk assessment. The nonlinear static pushover analysis was done to fine the performance point, spectral acceleration and corresponding spectral acceleration by Equivalent Linearization (EL) method given by Federal Emergency Management Agency (FEMA-440). The four damage states such as slight, moderate, extreme and collapse has been considered as per HAZUS-MR4. The seismic vulnerability in terms of fragility curves was developed to evaluate the damage probabilities based on HAZUS methodology. The discrete and cumulative damage probability was found for all the damage states of the building which shows the building at 0.16g experience slight damage whereas at 0.36g the moderate damage state equally becomes predominant.

A Bayesian approach to rapid seismic vulnerability assessment at urban scale

2017 ◽  
Vol 12 (1) ◽  
pp. 36-46 ◽  
Author(s):  
Gian Paolo Campostrini ◽  
Sabrina Taffarel ◽  
Giulia Bettiol ◽  
Maria Rosa Valluzzi ◽  
Francesca Da Porto ◽  
...  
Keyword(s):  
Bayesian Approach ◽  
Vulnerability Assessment ◽  
Seismic Vulnerability ◽  
Seismic Vulnerability Assessment
Sign in / Sign up

Export Citation Format

Share Document