What is the Smallest Earthquake Magnitude that Needs to be Considered in Assessing Liquefaction Hazard?

2019 ◽  
Vol 35 (3) ◽  
pp. 1441-1464 ◽  
Author(s):  
Russell A. Green ◽  
Julian J. Bommer
Keyword(s):  
Earthquake Magnitude ◽  
Risk Assessments ◽  
Soil Profiles ◽  
Building Structures ◽  
Liquefaction Hazard ◽  
Soil Deposits ◽  
Earthquake Size ◽  
Hazard And Risk ◽  
Hazard Assessments ◽  
Potential Impact

Probabilistic assessments of the potential impact of earthquakes on infrastructure entails the consideration of smaller magnitude events than those generally considered in deterministic hazard and risk assessments. In this context, it is useful to establish if there is a magnitude threshold below which the possibility of triggering liquefaction can be discounted because such a lower bound is required for probabilistic liquefaction hazard analyses. Based on field observations and a simple parametric study, we conclude that earthquakes as small as moment magnitude 4.5 can trigger liquefaction in extremely susceptible soil deposits. However, for soil profiles that are suitable for building structures, the minimum earthquake magnitude for the triggering of liquefaction is about 5. We therefore propose that in liquefaction hazard assessments of building sites, magnitude 5.0 be adopted as the minimum earthquake size considered, while magnitudes as low as 4.5 may be appropriate for some other types of infrastructure.

scholarly journals Potential impact of earthquakes during the 2020 COVID-19 pandemic

2020 ◽  
pp. 875529302095032
Author(s):  
Vitor Silva ◽  
Nicole Paul
Keyword(s):  
Seismic Events ◽  
Contemporary History ◽  
Virus Spread ◽  
Risk Map ◽  
Software Packages ◽  
Contingency Plans ◽  
Emerging Virus ◽  
Hazard And Risk ◽  
Potential Impact ◽  
The Impact

The 2020 COVID-19 pandemic caused a human and economic impact of unprecedented magnitude in contemporary history. In an effort to reduce the rate of infection, most governments implemented measures to increase social distancing and to strengthen the capacity of the healthcare system. The occurrence of earthquakes coincident with the pandemic may prevent the effective practice of such measures, and consequently cause an increase in the virus spread. This study analyzes the potential impact that seismic events may have on the infection rate within regions afflicted by both epidemics and earthquakes and explores open software packages that can be employed to simulate the impact of future destructive earthquakes on the spread of an emerging virus. Recent data on the number of confirmed cases at the national or subnational level were combined with a global seismic hazard and risk map to produce a combined index. This index highlights regions where preparedness and contingency plans should be developed to account for the possibility of COVID-19 outbreaks due to the earthquake impact.

Overview of Pipeline Geohazard Assessment Approaches and Strategies

2013 ◽  
Author(s):  
Moness Rizkalla ◽  
R. S. (Rod) Read
Keyword(s):  
Risk Assessments ◽  
Pipeline System ◽  
Mechanistic Models ◽  
Fitness For Purpose ◽  
Site Specific ◽  
Integrity Management ◽  
Hazard And Risk ◽  
Geohazard Risk ◽  
Geohazard Assessment ◽  
Do So

Undertaking a systematic pipeline geohazard assessment may be driven by the design and regulatory permitting needs for proposed new pipelines or as an input to the integrity management of operating pipeline assets. Yet the leading international pipeline codes do not provide explicit direction on undertaking such assessments, rather providing considerable latitude in the guidance to do so which in turn provides several options. The methods for identifying and assessing the potential likelihood and severity of geohazards vary significantly, from purely expert judgment-based approaches relying largely on visual observations of geomorphology to analytically-intensive methods incorporating phenomenological and/or mechanistic models and route, pipeline properties and, where applicable, operational monitoring data. Each of these methods can be used to assess hazard and risk associated with specific geohazards in terms of qualitative, semi-quantitative or quantitative approaches provided that associated underlying assumptions are clearly understood. Some of these methods are better suited to provide a continuous contiguous geohazard risk assessment for a pipeline system while others are better suited for localized site-specific risk assessments. Following a brief review of pipeline codes, this paper provides an overview of the range of pipeline geohazard assessment approaches and explores the “fitness for purpose” strategy that allows for continuing improvement during design stages and into operations.

scholarly journals Liquefaction Hazard Mapping Based on LPI (Liquefaction Potential Index) At Jepara, Indonesia

2020 ◽  
Vol 9 (4) ◽  
pp. 1611-1617
Keyword(s):  
Soil Analysis ◽  
Empirical Method ◽  
Earthquake Magnitude ◽  
Hazard Mapping ◽  
Penetration Test ◽  
Liquefaction Potential ◽  
Liquefaction Potential Index ◽  
Potential Index ◽  
Liquefaction Hazard ◽  
Potential Level

Liquefaction is a phenomenon of loss of strength of the soil layers caused by earthquake vibration. Liquefaction causes the soil to be in a liquid – like state, especially on sandy soil. Analysis of liquefaction potential was performed by using the semi-empirical method by calculating the Safety Factor (SF) based on Standard penetration Test (SPT) and Cone Penetration test (CPT) data. After the SF value was obtained, then the Liquefaction Potential Index (LPI) was calculated to determine the level of potential liquefaction in the study area to further produce a liquefaction potential map based on the liquefaction potential index. Based on the results of the calculation of the LPI, the level of liquefaction potential in the study area was very low when the earthquake magnitude is 5 Mw because the Liquefaction Potential Index (LPI) = 0. When the earthquake magnitude is 6 Mw, 7 Mw, 8 Mw, and 9 Mw, most of the investigation area has low potential level and there are some points that a high potential level.

ENGINEERING CHARACTERISTICS AND EARTHQUAKE RESPONSE ANALYSIS OF GROUND

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Haruyuki Yamamoto ◽  
Munkhunur Togtokhbuyan
Keyword(s):  
Shear Modulus ◽  
Ground Surface ◽  
Response Analysis ◽  
Soil Profiles ◽  
Lumped Mass ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Natural Period ◽  
Soil Deposits ◽  
Computational Procedures

One-dimensional layered soil lumped mass ground response analysis was conducted for the representative site in Ulaanbaatar, Mongolia. The surficial geology of the site is predominantly composed of the gravely and sandy soil typical of this region in the central part of Ulaanbaatar. The natural period of soil profiles needs to be investigated under several circumstances. For example, these parameters-based study has indicated that damage due to earthquakes occurs when the natural periods, T1 and T2, of the ground are closer to that of a superstructure. Various computational procedures or methods have been proposed for this kind of the ground response analysis. In this paper, the numerical analysis method such as the lumped mass method within eigenvalue analysis is used to determine the natural periods of the ground. The ground surface, soil deposits, and bedrock are assumed to be horizontal. The soil deposits are subjected to shear deformation such as shear modulus, G, on the other hand, excitation of vibration could be a shear modulus on each layer. As well as to determine an engineering bedrock depth in the site, the methodology that is utilized in this paper is focused on the use of the correlation between SPT-N value and soil elastic Young's modulus, E, in the soil profiles, and used over 100 boreholes data with SPT-N values in the vicinity of Ulaanbaatar.

How Chemicals Are Regulated in the European Union: A Commentary

2011 ◽  
Vol 2 (2) ◽  
pp. 183-185
Author(s):  
Dan Jørgensen
Keyword(s):  
Risk Assessment ◽  
European Union ◽  
Hazard Assessment ◽  
Chemical Compounds ◽  
Risk Assessments ◽  
The European Union ◽  
Advantages And Disadvantages ◽  
Assessment Approach ◽  
The Subject ◽  
Hazard Assessments

Professor Ragnar Lofstedt has written a very interesting and thought provoking paper “Risk versus Hazard Assessment – How to Regulate in the 21st Century”. The paper reflects upon the advantages and disadvantages of using risk assessments compared to hazard assessments of chemical compounds. It investigates the debate that has been going on in recent years in Europe between regulators, politicians, NGOs and industry on the subject.This commentary will discuss some of the assumptions that the analysis rests on as well as some of the conclusions that are presented in the paper.First, the commentary will discuss the definition and critique of the “risk assessment” approach that Lofstedt presents. The commentary here concludes that Lofstedt's analysis of risk assessment does not take sufficiently into account the fact that risks can not always be calculated in an exact way because uncertainty rather than certainty is the condition when analysing chemicals.

Assessing the risk from emerging infections

2009 ◽  
Vol 137 (11) ◽  
pp. 1521-1530 ◽  
Author(s):  
D. MORGAN ◽  
H. KIRKBRIDE ◽  
K. HEWITT ◽  
B. SAID ◽  
A. L. WALSH
Keyword(s):  
Systematic Approach ◽  
Animal Health ◽  
Good Evidence ◽  
Risk Assessments ◽  
Qualitative Assessment ◽  
Emerging Infections ◽  
Horizon Scanning ◽  
Threat Level ◽  
Potential Impact ◽  
The Uk

SUMMARYEmerging infections pose a constant threat to society and can require a substantial response, thus systems to assess the threat level and inform prioritization of resources are essential. A systematic approach to assessing the risk from emerging infections to public health in the UK has been developed. This qualitative assessment of risk is performed using algorithms to consider the probability of an infection entering the UK population, and its potential impact, and to identify knowledge gaps. The risk assessments are carried out by a multidisciplinary, cross-governmental group of experts working in human and animal health. This approach has been piloted on a range of infectious threats identified by horizon scanning activities. A formal risk assessment of this nature should be considered for any new or emerging infection in humans or animals, unless there is good evidence that the infection is neither a recognized human disease nor a potential zoonosis.

scholarly journals Disaster Mitigation for Palu City Residents in Dealing with Liquefaction Disasters in Accordance of Spatial Patterns of Palu City, Central Sulawesi Province, Indonesia.

2020 ◽  
Vol 5 (4) ◽  
pp. 219-226
Author(s):  
Yudi Kuswandi ◽  
Jossi Erwindi ◽  
Moh. Sapari Dwi Hadian ◽  
Dicky Muslim
Keyword(s):  
Shallow Groundwater ◽  
Geological Structure ◽  
Disaster Mitigation ◽  
Building Structures ◽  
Richter Scale ◽  
Liquefaction Hazard ◽  
Geological Conditions ◽  
Ancient Times ◽  
Strength And Stiffness ◽  
High Level

Potential natural hazards in Palu City by paying attention to the real physical characteristics of Palu City are categorized as having a high level of disaster hazard. The geological character of both the geological structure and geological engineering in the Palu region shows the great potential for geological disaster hazards. On September 28, 2018, at 18: 02 CIT, an earthquake measuring 7.4 on the Richter scale, the quake's center located in 26 km of Donggala district and 80 km northwest of Palu City. By observing the epicenter's location and the depth of the hypo-central earthquake, it appears that this shallow earthquake occurred due to activity in the Palu Koro fault zone. This fault is the most active in Sulawesi and is the most active in Indonesia with a movement of 7 cm per year. Liquidity disasters or ground liquefaction are also the effects of an earthquake. Shocks a massive quake causes the soil to melt this thing occurs when the saturated soil loses strength and stiffness due to stress. The Petobo area and the Balaroa - Perumnas are close to the Palu Koro active fault line and the land in the area is composed of soft material from the sedimentation process. This area is shallow groundwater with high soil permeability values, namely in the Petobo area and Perumnas - Balaroa. The purpose of this study is to analyze the potential liquefaction disaster in Palu City and analyze the Palu City resident ability against Liquefaction Hazard Prone. This research uses a descriptive qualitative analysis method. Potential liquefaction disasters were analyzing qualitatively based on geological conditions and disaster locations. Disaster mitigation capabilities were analyzed qualitatively based on the Palu City Spatial Pattern. One of the hazards caused by an earthquake that has the potential to be a disaster in Palu City is liquefaction. The ability of residents to mitigate liquefaction in Palu City is influenced by local wisdom which is reflected in ancient times when people lived in the highlands or hills. the concept of building structures, land use, and spatial planning patterns in Palu City which can reduce the threat of liquefaction.

scholarly journals Macroseismic intensity attenuation equations for Central Asia earthquakes

2021 ◽  
Vol 929 (1) ◽  
pp. 012029
Author(s):  
T U Artikov ◽  
R S Ibragimov ◽  
T L Ibragimova ◽  
M A Mirzaev
Keyword(s):  
Seismic Hazard ◽  
Central Asia ◽  
Seismic Intensity ◽  
Macroseismic Intensity ◽  
Earthquake Magnitude ◽  
Source Depth ◽  
Strong Earthquakes ◽  
Intensity Attenuation ◽  
Hazard Assessments ◽  
Macroseismic Survey

Abstract Based on macroseismic survey data for strong earthquakes in Central Asia, the coefficients of attenuation of seismic intensities with distance in the Blake-Shebalin- and Kovesligethy -type equations were refined. A new generalized dependence of macroseismic intensity attenuation on distance, taking into account the depth of the earthquake hypocentre, were obtained. Relations between the minor and major axes of the ellipse approximating real isoseists depending on the shaking strength, source depth and earthquake magnitude were found. With the example of the territory of eastern Uzbekistan, the influence of the choice of the law of seismic intensity attenuation with distance on the obtained seismic hazard assessments is investigated.

Tsunami-based evidence for large eastern Aleutian slip during the 1957 earthquake

2018 ◽  
Vol 91 (03) ◽  
pp. 1045-1058 ◽  
Author(s):  
Frances R. Griswold ◽  
Breanyn T. MacInnes ◽  
Bretwood Higman
Keyword(s):  
Near Field ◽  
Earthquake Magnitude ◽  
East Central ◽  
Field Surveys ◽  
The Pacific ◽  
Order Of Magnitude ◽  
Local Impact ◽  
Potential Impact ◽  
Run Up ◽  
Eastern Half

AbstractThe Aleutian subduction zone is capable of generating magnitude ~9 earthquakes that have local impact and broadcast their destructive power across the Pacific through tsunamis. Field surveys of the tsunami from the 1957 Great Aleutian earthquake (reported M w 8.6) indicate a tsunami amongst the largest of the twentieth century. In the eastern half of the rupture zone, stranded logs record up to 18 m run-up in the Islands of Four Mountains (IFM) and 32±2 m on Unalaska Island. In conjunction with archaeological studies in the region, these observations show the potential impact of tsunamis on the ancient peoples in the IFM. Simulation of the near-field tsunami produced from the published slip distribution of 1957 is almost an order of magnitude smaller than all field observations. Increasing the earthquake magnitude and amount of eastern slip used in forward models of the tsunami demonstrate that run-up observations can be achieved throughout the eastern Aleutians if the earthquake was more than twice as large—at least M w 8.8 earthquake with 10–20 m of eastern slip. Additionally, up to five possible IFM paleotsunami deposits agree with the regional picture of regular large events, illustrating the circum-Pacific tsunami hazard from the east-central Aleutians.

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