Earthquake Vulnerability Assessment for Urban Areas Using an ANN and Hybrid SWOT-QSPM Model

Tabriz city in NW Iran is a seismic-prone province with recurring devastating earthquakes that have resulted in heavy casualties and damages. This research developed a new computational framework to investigate four main dimensions of vulnerability (environmental, social, economic and physical). An Artificial Neural Network (ANN) Model and a SWOT-Quantitative Strategic Planning Matrix (QSPM) were applied. Firstly, a literature review was performed to explore indicators with significant impact on aforementioned dimensions of vulnerability to earthquakes. Next, the twenty identified indicators were analyzed in ArcGIS, a geographic information system (GIS) software, to map earthquake vulnerability. After classification and reclassification of the layers, standardized maps were presented as input to a Multilayer Perceptron (MLP) and Self-Organizing Map (SOM) neural network. The resulting Earthquake Vulnerability Maps (EVMs) showed five categories of vulnerability ranging from very high, to high, moderate, low and very low. Accordingly, out of the nine municipality zones in Tabriz city, Zone one was rated as the most vulnerable to earthquakes while Zone seven was rated as the least vulnerable. Vulnerability to earthquakes of residential buildings was also identified. To validate the results data were compared between a Multilayer Perceptron (MLP) and a Self-Organizing Map (SOM). The scatter plots showed strong correlations between the vulnerability ratings of the different zones achieved by the SOM and MLP. Finally, the hybrid SWOT-QSPM paradigm was proposed to identify and evaluate strategies for hazard mitigation of the most vulnerable zone. For hazard mitigation in this zone we recommend to diligently account for environmental phenomena in designing and locating of sites. The findings are useful for decision makers and government authorities to reconsider current natural disaster management strategies.

Directing Housing Developments for Achieving Earthquake Disasters Safety in Indonesia

The high number of fatalities and damage to buildings in the areas most affected by the earthquake should affect how to build houses. Especially in the case of self-housing, the community’s trauma will immediately encourage them to increase the safety of their buildings. However, early studies do not confirm so. Although it looks pretty built concerning the earthquake, the number of self-help houses found in post-disaster construction shows that concern for structural safety is still below expectations. This paper examines how safety precautions affect the way people build their homes. We discussed current housing developments geared towards earthquake vulnerability in Indonesia and found that housing security, in general, is still far from expectations. Learning from many post-disaster cases informs us that we must take radical and massive action regarding housing schemes and building structures to reduce the toll caused by destructed weak houses under every hit of an earthquake.

KECEPATAN GELOMBANG GESER (VS) DAN KETEBALAN SEDIMEN (H) DI KABUPATEN KLATEN DARI DATA MIKROTREMOR

Research on Shear Wave Velocity (vs) and Sediment Thickness (h) in Klaten Regency, Central Java from field microtremor data aims to determine the thickness of sediment or soft sediment as one factor of high and low earthquake vulnerability. Microtremor data was collected using a three-component TDS 303 seismometer covering 111 measuring points in the Klaten Regency area. In this study, the sediment thickness was calculated using the equation shear wave velocity (vs) divided by four times the dominant frequency (fg). The dominant frequency (fg) value is obtained from the HVSR curve. In contrast, the shear wave velocity value (vs) used in this study is the inversion value of the HVSR curve, which is modeled based on borlog data at the Wedi Church, equated for all measurement points. The map of the shear wave velocity distribution at each microtremor measuring point has a vs value; this value is used to calculate the thickness of the sediment at each end. So that the distribution of the thickness value of the sediment at each point is obtained, then a thickness map is made covering the study area. The results showed that, in general, the research area has a Vs value in the effects of the HVSR curve inversion ranging from 130 m/s to 570.83 m/s, Vs average 275.68 m/s. The areas with vs are relatively high in the southern part of Gantiwarno, Wedi, and Bayat subdistricts directly adjacent to Gunung Kidul. Areas with relatively low-value of vs are in Prambanan Subdistrict, Northern Wedi Subdistrict, Trucuk Subdistrict, Jogonalan Subdistrict, South Klaten District, Central Klaten District, and Kalikotes Subdistrict. For sediment thickness (h) ranges from 5.105 m to 113.648 m. Areas with relatively high sediment thickness are located in parts of Wedi Subdistrict with a thickness of up to 110 m. Areas with medium thickness (around 60 to 90 m) are in the Gantiwarno sub-district, Prambanan district, and the southern part of the Jogonalan sub-district. In Bayat District, it has a low thickness (about 5 to 30 m) located in the proves and mountains of the Paseban area and the tomb of Sunan Pandanaran. The result shows that areas with high sediment thickness, namely in Wedi District, have a high level of earthquake vulnerability.

Rapid Seismic Vulnerability and Risk Assessment of Kermanshah Historic Mosques

Background: In this research a rapid vulnerability and risk assessment at a territorial level is performed. Methods: The methodology used, initially proposed for ancient masonry churches, is extended and applied to ten historic masonry mosques in Kermanshah city. The method could be considered as preliminary risk assessment approach of historic structures, refers to LV0 method, since the used methodology requires simple qualitative information. It involves the application of three distinct tools; the exposure, the seismic hazard, and the seismic vulnerability. Results: The comparisons among the obtained results, by considering also the damages suffered during the last earthquakes and war blasts, validate the methodology proposed, capable of providing a seismic risk scoring at a territorial level also for ancient masonry mosques. As known, through this kind of approach, important information is obtained in order to manage and to mitigate the seismic risk of a certain territorial asset. The results show that all ten mosques has medium earthquake vulnerability condition. Emad e Doleh mosque is the most vulnerable case with vulnerability of 34. Navab mosque is located on the most hazardous place. Furthermore, the seismic vulnerability map and seismic risk indices are presented for all the investigated mosques. Conclusion: The obtained results are useful for ranking the priorities and for preliminary defining an interventions plan to be examined in detail with additional quantitative investigations carried out with more refined approaches.