Liquefaction evaluation guidelines for practicing engineering and geological professionals and regulators

2001 ◽  
Vol 7 (4) ◽  
pp. 301-320 ◽  
Author(s):  
Marshall Lew
Keyword(s):  
Seismic Hazard ◽  
Hazard Analysis ◽  
Analytical Techniques ◽  
The United States ◽  
Lateral Spreading ◽  
The State ◽  
Hazard Mapping ◽  
Liquefaction Potential ◽  
Liquefaction Hazard ◽  
Flow Slides

Abstract Liquefaction is a seismic hazard that must be evaluated for a significant percentage of the developable areas of California. The combination of the presence of active seismic faults, young loose alluvium, and shallow ground water are the ingredients that could result in the occurrence of liquefaction in many areas of California. These ingredients are also found in other seismically active areas of the United States and the world. The state of California, through the Seismic Hazard Mapping Act of 1990, has mandated that liquefaction hazard be determined for new construction. On a parallel track, the Uniform Building Code, since 1994, has provisions requiring the determination of liquefaction potential and mitigation of related hazards, such as settlement, flow slides, lateral spreading, ground oscillation, sand boils, and loss of bearing capacity. Fortunately, the state of knowledge has now evolved to where there are field exploration methods and analytical techniques to estimate the liquefaction potential and the possible consequences arising from the occurrence of liquefaction. There are some areas that still need further research. Mitigation for liquefaction has become more commonplace and confidence in these techniques has been increased based on the relatively successful performance of improved sites in the past several major earthquakes. Unfortunately, not all practicing engineering and geological professionals and building officials are knowledgeable about the current state-of-practice in liquefaction hazard analysis and mitigation. Thus, it was considered necessary to develop a set of guidelines to aid professionals and building officials, based on California's experience with the current practice of liquefaction hazard analysis and mitigation. Although the guidelines reported in this paper were written specifically for practice in California, it is believed that guidelines can benefit practitioners to evaluate liquefaction hazard in all seismic regions.

Effects of temporal variations in seismicity on seismic hazard

1981 ◽  
Vol 71 (1) ◽  
pp. 321-334
Author(s):  
Robin K. McGuire ◽  
Theodore P. Barnhard
Keyword(s):  
United States ◽  
Seismic Hazard ◽  
Seismic Activity ◽  
Time Window ◽  
Hazard Analysis ◽  
The United States ◽  
Temporal Variations ◽  
Seismogenic Zone ◽  
Eastern United States ◽  
Ground Shaking

abstract The accuracy of stationary mathematical models of seismicity for calculating probabilities of damaging shaking is examined using the history of earthquakes in China from 1350 A.D. to 1949 A.D. During this time, rates of seismic activity varied periodically by a factor of 10. Probabilities of damaging shaking are calculated in 62 cities in North China using 50 yr of earthquake data to estimate seismicity parameters; the probabilities are compared to statistics of damaging shaking in the same cities for 50 yr following the data window. These comparisons indicate that the seismic hazard analysis is accurate if: (1) the maximum possible earthquake size in each seismogenic zone is determined from the entire seismic history rather than from a short-time window; and (2) the future seismic activity can be estimated accurately. The first condition emphasizes the importance of realistically estimating the maximum possible size of earthquakes on faults. The second indicates the need to understand possible trends in seismic activity where these exist, or to develop an earthquake prediction capability with which to estimate future activity. Without the capability of estimating future seismicity, stationary models provide less accurate but generally conservative indications of seismic ground-shaking hazard. In the United States, the available earthquake history is brief but gives no indication of changing rates of activity. The rate of seismic strain release in the Central and Eastern United States has been constant over the last 180 yr, and the geological record of earthquakes on the southern San Andreas Fault indicates no temporal trend for large shocks over the last 15 centuries. Both observations imply that seismic activity is either stationary or of such a long period that it may be treated as stationary for seismic hazard analyses in the United States.

scholarly journals Introduction and Application of a Simple Probabilistic Liquefaction Hazard Analysis Program: HAZ45PL Module

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jui-Ching Chou ◽  
Pao-Shan Hsieh ◽  
Po-Shen Lin ◽  
Yin-Tung Yen ◽  
Yu-Hsi Lin
Keyword(s):  
Hazard Analysis ◽  
Probabilistic Approach ◽  
Soil Liquefaction ◽  
Shallow Foundation ◽  
Evaluation Procedure ◽  
Liquefaction Potential ◽  
Probability Map ◽  
Liquefaction Hazard ◽  
Potential Map ◽  
The Government

The 2016 Meinong Earthquake hit southern Taiwan and many shallow foundation structures were damaged due to soil liquefaction. In response, the government initiated an investigation project to construct liquefaction potential maps for metropolitans in Taiwan. These maps were used for the preliminary safety assessment of infrastructures or buildings. However, the constructed liquefaction potential map used the pseudo-probabilistic approach, which has inconsistent return period. To solve the inconsistency, the probabilistic liquefaction hazard analysis (PLHA) was introduced. However, due to its complicated calculation procedure, PLHA is not easy and convenient for engineers to use without a specialized program, such as in Taiwan. Therefore, PLHA is not a popular liquefaction evaluation procedure in practice. This study presents a simple PLHA program, HAZ45PL Module, customized for Taiwan. Sites in Tainan City and Yuanlin City are evaluated using the HAZ45PL Module to obtain the hazard curve and to construct the liquefaction probability map. The liquefaction probability map provides probabilities of different liquefaction potential levels for engineers or owners to assess the performance of an infrastructure or to design a mitigation plan.

scholarly journals Probabilistic Seismic Hazard Analysis of Sitamarhi near Bihar-Nepal Region

2021 ◽  
Author(s):  
Abhik Paul ◽  
Pradipta Chakrabortty ◽  
Avijit Burman ◽  
Sapan Kumar
Keyword(s):  
Seismic Hazard ◽  
Large Scale ◽  
Hazard Analysis ◽  
The United States ◽  
Probabilistic Seismic Hazard Analysis ◽  
Seismic Hazard Analysis ◽  
United States Geological Survey ◽  
Probabilistic Seismic Hazard ◽  
Maximum Magnitude ◽  
Earthquake Data

Abstract This article presents the results of a probabilistic seismic hazard analysis (PSHA) for Sitamarhi, Bihar considering the region-specific maximum magnitude and ground motion prediction equation (GMPEs). North Bihar region is one of the seismically unstable areas in India facing several destructive earthquakes for the Himalayan Mountains that was created by the collision of Indian and Eurasian plate. The Gutenberg-Richter (G-R) seismic hazard parameter ‘a’ and ‘b’ have been evaluated by considering the available local earthquake data. Earthquake data were collected from the United States geological survey (USGS), Indian Meteorological Department (IMD), New Delhi, Seismotectonic Atlas of India (GIS 2000) within 500 km radius of the study area, and 62 seismotectonic sources were identified and considered in this study. Seismic source zones for the region have been defined based on large-scale geological features, which are used for assigning the maximum possible earthquake potential. Estimated PGA values are 0.89 g and 0.61 g for the 2% and 10% probabilities of exceedance in 50 years. The results showed that West Patna fault and Sitamarhi Fault are the two main faults, which contribute maximum in the peak ground acceleration (PGA) values for Sitamarhi region.

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.

Seismic Hazard Assessment and Remediation of Pipelines

1998 ◽  
Author(s):  
Trevor P. Fitzell ◽  
Dharma K. Wijewickreme
Keyword(s):  
Seismic Hazard ◽  
Treatment Options ◽  
Seismic Hazard Assessment ◽  
Lateral Spreading ◽  
Hazard Mapping ◽  
Directional Drilling ◽  
Modeling And Analysis ◽  
Response Planning ◽  
Geotechnical Investigations ◽  
Natural Gas Transmission

The performance of pipeline systems under seismic loading is an important consideration in regions subject to earthquakes. This paper briefly describes a study to evaluate the vulnerability of a natural gas transmission system to seismic hazards, along with some of the remedial treatment options which are being considered. The study was carried out for BC Gas Utility Ltd. in the Greater Vancouver Region of British Columbia. The results of the study are being used by BC Gas in emergency response planning and remedial treatment activities to limit their risk exposure. The paper describes the approach used to assess liquefaction and lateral spreading risks, and remedial treatment options which were considered. This involved generation of design seismic ground motions, seismic hazard mapping, geotechnical investigations to determine the subsurface conditions, and geotechnical and structural numerical modeling and analysis to assess pipeline performance and remedial treatment options. Several different approaches to remediation are described; one involves ground treatment to reduce the risk of unacceptable ground deformations; another involves structural modifications to improve the resistance of the pipeline to seismic motions, while another makes use of directional drilling to re-align the pipe below infirm areas.

CU-PSHA: A MATLAB Software for Probabilistic Seismic Hazard Analysis

2014 ◽  
Vol 08 (04) ◽  
pp. 1450008 ◽  
Author(s):  
Santi Pailoplee ◽  
Chitti Palasri
Keyword(s):  
Seismic Hazard ◽  
Hazard Analysis ◽  
Earthquake Hazard ◽  
Hazard Mapping ◽  
Earthquake Hazards ◽  
Flexible Tool ◽  
Matlab Software ◽  
Ground Shaking ◽  
Magnitude Distribution ◽  
Ground Motion Attenuation

In this study, an open source MATLAB software, called CU-PSHA, is developed in order to analyze probabilistic earthquake hazards. This software aims to provide a user friendly and flexible tool for evaluating reliable earthquake hazard estimates. With the CU-PSHA, the probability of distances between the earthquake sources and the study site can be estimated. Two choices for the estimation of earthquake frequency–magnitude distribution, the exponential magnitude distribution and the characteristic earthquake models, are provided. Some strong ground–motion attenuation models are available for both shallow crustal and subduction zone earthquakes. The probability of exceedance of any individual given ground shaking value can be obtained, allowing the display of a seismic hazard curve. In addition with the supplementary MATLAB scripts, this CU-PSHA software can be employed in general seismic hazard mapping, for both ground shaking level and probability of occurrence, in any specific given time span.

Laboratory Study and Evaluation of the Loess Liquefaction under Random Seismic Loading

2012 ◽  
Vol 594-597 ◽  
pp. 1805-1810 ◽  
Author(s):  
Jun Wang ◽  
Lan Min Wang ◽  
Hai Ping Ma ◽  
Qian Wang ◽  
Ping Wang ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Laboratory Study ◽  
Hazard Analysis ◽  
Seismic Loading ◽  
Test Results ◽  
Liquefaction Potential ◽  
Passenger Rail ◽  
Triaxial Apparatus ◽  
Forecasting Method ◽  
Rail Line

By using the DSD-160 dynamic triaxial apparatus, liquefaction experiments under random seismic loading of the saturation original samples from a passenger rail line which located in the loess tableland in china was tested. Based on the test results, connected with the forecasting method of the liquefaction test under random seismic loading and the results of seismic hazard analysis, the liquefaction potential of the saturation loess from different regions in the passenger rail line is distinguished. Moreover, the predictions include 50 years probability of exceedance 10% and 2%of the loess liquefaction potential of the sites mentioned above is obtained.

scholarly journals Liquefaction Potential Analysis in Bucharest City as a Result of the Ground Shaking during Strong Vrancea Earthquakes

2021 ◽  
Vol 8 (2) ◽  
pp. 113-138
Author(s):  
ANDREI BALA ◽  
DIETER HANNICH
Keyword(s):  
Lateral Spreading ◽  
German Research Foundation ◽  
Liquefaction Potential ◽  
Strong Earthquakes ◽  
Ground Shaking ◽  
Vrancea Earthquakes ◽  
Liquefaction Hazard ◽  
Institute Of Technology ◽  
The University ◽  
Bucharest City

Bucharest, the capital of Romania with about 2.5 million inhabitants, is frequently struck by intense, damaging earthquakes (2–3 events per century). The Collaborative Research Center 461 (CRC-461) entitled: “Strong Earthquakes - a Challenge of Geosciences and Civil Engineering” was established in July 1996 and ended in December 2007, but some projects continued until 2010. It was funded by the German Research Foundation and involved the University of Karlsruhe which today belongs to Karslruhe Institute of Technology. The CRC aimed strategic research in the field of strong earthquakes with regional focus on the Vrancea seismic events in Romania. Between 1995–2007 several research works were done in Romania, with the support of several Romanian research institutes and the University of Bucharest. One of the research questions was to study the occurring of liquefaction during strong earthquakes within the shallow sandy layers in Bucharest. In suitable conditions, strong earthquakes can cause, under certain geologic conditions, liquefaction and therewith ground failure as sand boils, lateral spreading, or differentiated subsidence. In the present paper we analyze the liquefaction risk for Bucharest. For this purpose, at 10 representative sites in Bucharest, Seismic Cone Penetration Tests (SCPTu) were executed. An area-wide evaluation of the liquefaction probability in Bucharest was established. The factor of safety (FS) against liquefaction and the probability of liquefaction (PL) were computed from the obtained test-data. For the first time, maps of the liquefaction potential index (Li) for Bucharest were outlined. This map shows how severe the liquefaction phenomena might be during strong Vrancea earthquakes in Bucharest, amplifying the site effects. Keywords: hydrogeologic conditions, liquefaction probability, liquefaction hazard, Bucharest city, strong Vrancea earthquakes

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