Site Effects of the 2003 Bam, Iran, Earthquake

2005 ◽  
Vol 21 (1_suppl) ◽  
pp. 125-136 ◽  
Author(s):  
Mohammad Kazem Jafari ◽  
Mohammad Reza Ghayamghamian ◽  
Mohammad Davoodi ◽  
Mohsen Kamalian ◽  
Abdollah Sohrabi-Bidar
Keyword(s):  
High Frequency ◽  
Site Effects ◽  
Site Effect ◽  
Site Amplification ◽  
Frequency Characteristics ◽  
Ground Conditions ◽  
A Site ◽  
The City

The site amplification characteristics of the 2003 Bam, Iran, earthquake were investigated based on geological studies as well as geophysical, microtremor and aftershock measurements conducted by IIEES in the study area. A site effect microzonation map was prepared classifying the ground conditions of the city into five distinct categories, based on their stiffness, thickness, and frequency characteristics. The highest percentage of damage was concentrated in sites with stiff shallow and medium depth soils, which possessed considerable amplification potentials in high frequency ranges.

Analysis of Site Amplification Phenomena: An Application in Ripabottoni for the 2002 Molise, Italy, Earthquake

2004 ◽  
Vol 20 (1_suppl) ◽  
pp. 107-118 ◽  
Author(s):  
Marco Massa ◽  
Gabriele Ferretti ◽  
Andrea Cevasco ◽  
Luana Isella ◽  
Claudio Eva
Keyword(s):  
Fundamental Frequency ◽  
Site Effects ◽  
Site Response ◽  
Site Amplification ◽  
Simulation Code ◽  
Dimensional Simulation ◽  
Molise Region ◽  
A Site ◽  
The University ◽  
The Village

The geophysical working group of the University of Genoa conducted a field experiment to analyze site amplification effects in Ripabottoni, a village in the Molise region of Italy. We used both noise and earthquake recordings, combined with detailed geologic and geotechnical surveys, to define site amplification phenomena. The site effects determination was obtained using the Nakamura technique and the H/V spectral analysis applied to earthquake recordings. The results were validated by applying a one-dimensional simulation code. The computed spectral ratios point out three different typologies of site effects: the southern sector of Ripabottoni is characterized by an absence of local amplification phenomena; the central sector of the village shows a local amplification phenomena with a fundamental frequency of 4–6 Hz; and the northeastern side of the village shows a site response at a fundamental frequency between 2–3 Hz.

scholarly journals Site Effect Assessment in Ulaanbaatar, Mongolia through Inversion Analysis of Microtremor H/V Spectral Ratios

Geosciences ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 228 ◽  
Author(s):  
Zorigt Tumurbaatar ◽  
Hiroyuki Miura ◽  
Tsoggerel Tsamba
Keyword(s):  
Joint Inversion ◽  
Earthquake Hazard ◽  
Site Effect ◽  
Site Amplification ◽  
Disaster Mitigation ◽  
Spectral Ratios ◽  
Southeastern Part ◽  
Inversion Technique ◽  
A Site ◽  
Inversion Analysis

Due to the population growth and urban sprawl in Ulaanbaatar city (UB), Mongolia, hazard and risk analysis for future earthquakes have become an important issue for disaster mitigation planning. Evaluation of a site effect is one of the essential parts of the earthquake hazard estimation in this area. The site effect can be evaluated by site amplifications calculated from shear-wave velocity (VS) models including from bedrock to surface layers. However, it is difficult to assess the pattern of the site effects in UB because shallow mostly up to 15 m and a small number of investigated VS models are available in previous studies. In this study, the VS models are estimated using microtremor data at 50 sites and inversion analysis is applied to the observed data in order to evaluate site amplifications in UB. In particular, the joint inversion technique based on a diffuse field approach is applied to estimate the VS structures at three sites using the observed horizontal-to-vertical (H/V) spectral ratios and surface wave phase velocities obtained by Odonbaatar (2011). The rest of the sites are estimated by the single inversion technique using the observed microtremor H/V spectral ratios considering the results of the joint inversions. The seismic microzoning in UB is performed based on the site amplifications computed from the inverted VS models to characterize the pattern of seismic hazard. The result shows the largest site amplification zone is computed along the Tuul river in the southeastern part of UB.

Modeling of Empirical Transfer Functions with 3D Velocity Structure

2021 ◽  
Author(s):  
Zhifeng Hu ◽  
Daniel Roten ◽  
Kim B. Olsen ◽  
Steven M. Day
Keyword(s):  
Material Properties ◽  
Site Effects ◽  
Velocity Structure ◽  
Transfer Functions ◽  
Site Response ◽  
Hazard Analysis ◽  
Earthquake Hazard ◽  
Site Effect ◽  
3D Models ◽  
Site Amplification

ABSTRACT Empirical transfer functions (ETFs) between seismic records observed at the surface and depth represent a powerful tool to estimate site effects for earthquake hazard analysis. However, conventional modeling of site amplification, with assumptions of horizontally polarized shear waves propagating vertically through 1D layered homogeneous media, often poorly predicts the ETFs, particularly, in which large lateral variations of velocity are present. Here, we test whether more accurate site effects can be obtained from theoretical transfer functions (TTFs) extracted from physics-based simulations that naturally incorporate the complex material properties. We select two well-documented downhole sites (the KiK-net site TKCH05 in Japan and the Garner Valley site, Garner Valley Downhole Array, in southern California) for our study. The 3D subsurface geometry at the two sites is estimated by means of the surface topography near the sites and information from the shear-wave profiles obtained from borehole logs. By comparing the TTFs to ETFs at the selected sites, we show how simulations using the calibrated 3D models can significantly improve site amplification estimates as compared to 1D model predictions. The primary reason for this improvement in 3D models is redirection of scattering from vertically propagating to more realistic obliquely propagating waves, which alleviates artificial amplification at nodes in the vertical-incidence response of corresponding 1D approximations, resulting in improvement of site effect estimation. The results demonstrate the importance of reliable calibration of subsurface structure and material properties in site response studies.

Global Justice at the Municipal Scale

2018 ◽  
Author(s):  
Fonna Forman ◽  
Teddy Cruz
Keyword(s):  
Urban Space ◽  
Global Justice ◽  
Local Governance ◽  
Global City ◽  
Way Of Thinking ◽  
A Site ◽  
The City

Cities or municipalities are often the most immediate institutional facilitators of global justice. Thus, it is important for cosmopolitans and other theorists interested in global justice to consider the importance of the correspondence between global theories and local actions. In this chapter, the authors explore the role that municipalities can play in interpreting and executing principles of global justice. They offer a way of thinking about the cosmopolitan or global city not as a gentrified and commodified urban space, but as a site of local governance consistent with egalitarian cosmopolitan moral aims. They work to show some ways in which the city of Medellín, Colombia, has taken significant steps in that direction. The chapter focuses especially on how it did so and how it might serve as a model in some important ways for the transformation of other cities globally in a direction more consistent with egalitarian cosmopolitanism.

Analysis of High Frequency Characteristics for a Meander Line Slow-wave Structure

2020 ◽  
Author(s):  
Zheng Wen ◽  
Jirun Luo ◽  
Yu Fan ◽  
Chen Yang ◽  
Fang Zhu ◽  
...  
Keyword(s):  
Slow Wave ◽  
High Frequency ◽  
Wave Structure ◽  
Slow Wave Structure ◽  
Frequency Characteristics ◽  
Meander Line

scholarly journals A Proposed Framework for Identification of Indicators to Model High-Frequency Cities

2021 ◽  
Vol 10 (5) ◽  
pp. 317
Author(s):  
Ahmad M. Senousi ◽  
Junwei Zhang ◽  
Wenzhong Shi ◽  
Xintao Liu
Keyword(s):  
Urban Studies ◽  
Traffic Congestion ◽  
High Frequency ◽  
Urban Policy ◽  
Low Frequency ◽  
Highway Design ◽  
City Life ◽  
Cultural Affiliation ◽  
Internal Mobility ◽  
The City

A city is a complex system that never sleeps; it constantly changes, and its internal mobility (people, vehicles, goods, information, etc.) continues to accelerate and intensify. These changes and mobility vary in terms of the attributes of the city, such as space, time and cultural affiliation, which characterise to some extent how the city functions. Traditional urban studies have successfully modelled the ‘low-frequency city’ and have provided solutions such as urban planning and highway design for long-term urban development. Nevertheless, the existing urban studies and theories are insufficient to model the dynamics of a city’s intense mobility and rapid changes, so they cannot tackle short-term urban problems such as traffic congestion, real-time transport scheduling and resource management. The advent of information and communication technology and big data presents opportunities to model cities with unprecedented resolution. Since 2018, a paradigm shift from modelling the ‘low-frequency city’ to the so-called ‘high-frequency city’ has been introduced, but hardly any research investigated methods to estimate a city’s frequency. This work aims to propose a framework for the identification and analysis of indicators to model and better understand the concept of a high-frequency city in a systematic manner. The methodology for this work was based on a content analysis-based review, taking into account specific criteria to ensure the selection of indicator sets that are consistent with the concept of the frequency of cities. Twenty-two indicators in five groups were selected as indicators for a high-frequency city, and a framework was proposed to assess frequency at both the intra-city and inter-city levels. This work would serve as a pilot study to further illuminate the ways that urban policy and operations can be adjusted to improve the quality of city life in the context of a smart city.

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