Liquefaction Hazard Assessment Research Articles

Liquefaction potential analysis based on standard penetration test in coastal area (Case study: Loh Buaya, Rinca Island, Indonesia)

An area has liquefaction potential when it has a shallow groundwater level, loose sandy soil, and is prone to earthquakes. There are several areas with such criteria that have not been analysed for liquefaction potential. This study aims to analyse and plot the liquefaction potential in the coastal area of Loh Buaya, Rinca Island, East Nusa Tenggara Province. Soil investigation data, such as SPT, sieve analysis, and groundwater level, as well as earthquake history that occurred from 1922-2022, served as the main data for liquefaction potential analyses. The methods used were Ground Motion Equation Prediction (GMPE) to calculate Peak Ground Acceleration (PGA), Simplified Procedure, and Liquefaction Severity Index (LSI) to make a liquefaction hazard assessment. LSI scores were used to provide micro-zonation of liquefaction potential with Inverse Distance Weighted (IDW) interpolation in QGIS. The result obtained is very dense gravel has no liquefaction potential whereas loose sandy soil has very high in LSI classification because loose sandy soil has liquefaction potential up to 20 meters of depth. The applying of micro-zonation LSI by IDW interpolation method can estimate the potential level of liquefaction hazard on Loh Buaya, Rinca Island with limited soil investigation data.

Assessment of Liquefaction Hazard for Sites in Romania Using Empirical Models

This paper is focused on the evaluation of the liquefaction hazard for different sites in Romania. To this aim, a database of 139 ground motions recorded during Vrancea intermediate-depth earthquakes having moment magnitudes MW ≥ 6.0 is employed for the evaluation of the equivalent number of cycles for this seismic source. Several functional forms for the empirical evaluation of the equivalent number of cycles considering various seismological or engineering parameters are tested and evaluated. The regression analysis shows smaller uncertainties for the empirical models based on ground motion engineering parameters. Considering the lack of information in terms of engineering parameters, a simpler empirical model which accounts for the earthquake magnitude, source–site distance and soil conditions is selected for the liquefaction hazard analysis. Based on the proposed empirical model, specific magnitude scaling factors for Vrancea intermediate-depth earthquakes are proposed for the first time as well. The liquefaction hazard analysis is performed for sites whose seismic hazard is generated by either the Vrancea intermediate-depth seismic source or by local shallow crustal seismic sources. In the case of some of the selected sites, liquefaction phenomena were observed during past large-magnitude earthquakes. Unlike previous studies dealing with liquefaction analyses for sites in Romania, in this research, the hazard assessment is performed for various ground motion levels evaluated based on probabilistic seismic hazard assessment. Liquefaction hazard curves are constructed for each analyzed site. The results of the liquefaction hazard analysis show that this phenomenon is more likely to occur in the areas exposed to Vrancea intermediate-depth earthquakes, compared to the areas affected by local shallow earthquakes. In the case of the analyzed soil profiles from Bucharest, Craiova and Ianca, the minimum liquefaction safety factors less than one even for seismic hazard levels having mean return periods of 100 years and less.

Application into Assessment of Liquefaction Hazard and Geotechnical Vulnerability During Earthquake with High-Precision Spatial-Ground Model for a City Development Area

Application into Assessment of Liquefaction Hazard and Geotechnical Vulnerability During Earthquake with High-Precision Spatial-Ground Model for a City Development Area

Liquefaction severity assessment for the Anutapura Medical Center Area of Palu-Indonesia

A liquefaction hazard assessment for a particular location is important to reduce disasters that may occur in the future. The liquefaction severity assessment for the Anutapura Medical Centre region of Palu-Indonesia was carried out on various pairs between peak ground surface acceleration and earthquake magnitude. It was conducted by first determining the factor of safety for each existing soil layer and applying the formulation prepared by Iwasaki to measure Liquefaction Potential for the entire soil column. The possible severity of liquefaction at these locations was compared based on the limits set by the respective theories of Iwasaki and Papathanassiou. The results showed that the Anutapura Medical Centre location was very susceptible to liquefaction events with a very high potential level of ground surface damage based on the Iwasaki boundary line. The above-mentioned severity by Papathanassiou limits ranges from high to very high.

Assessment of Liquefaction Hazard and Mapping Based on Standard Penetration Tests in the Long Beach and Tuzla Regions of Cyprus

Cyprus is the third largest and populated island in the Mediterranean Sea, and is still rapidly expanding. Significant infrastructures, such as hotels, educational institutions, and large residential complexes, are being built. Historically, 15 destructive earthquakes were reported on Cyprus from 1896 to 2019 that caused structural damages and casualties. In this study, the liquefaction potential of Tuzla and Long Beach on the east coast of Cyprus is estimated using the standard penetration test (SPT) data from more than 200 boreholes at different locations at the sites. The overall results are presented in a liquefaction potential index obtained from the factor of safety (F.S.) coefficient. Both study areas are susceptible to liquefaction. Thus, liquefaction potential maps are prepared to identify hazards in Tuzla and Long Beach. Additionally, the average factor of the safety line was introduced for both sites to create a correlation between the liquefaction area and F.S. values of every borehole. The adopted approach precisely provides the liquefiable regions when compared with historical evidence, CPT measurements, surface geology aspects, and geospatial data. Additionally, the results prove that the liquefaction potential must be considered during the design stage of new infrastructure in these areas.

Site Characterization and Liquefaction Hazard Assessment for the Erenler Settlement Area (Sakarya Province, Turkey) Based on Integrated SPT-Vs Data

The focus of this study is to examine the soil properties and liquefaction potential of the Erenler center district in a critical tectonic zone that can produce large earthquakes, such as the North Anatolian Fault Zone (NAFZ). In this sense, 40 surface wave measurements and 52 geotechnical drillings were employed. Accordingly, the liquefaction potential index (LPI), liquefaction severity index (LSI), Ishihara boundary (IB) curve, and Ishihara-inspired index (LPIISH) liquefaction approaches from geotechnical and geophysical methods were used as integrated. All liquefaction analyses were examined for two scenarios, Mw: 7.4 1999 Izmit (amax: 0.41 g) and Mw: 7.0 1967 (amax: 0.28 g) Mudurnu. According to the analyses, almost all of the study area showed liquefaction risk in the Izmit scenario. In the Mudurnu scenario, liquefaction risk distribution decreased parallel to acceleration. The LPI, LPIISH, and IB liquefaction risk results for both scenarios support each other. On the other hand, it was determined that the probability of liquefaction was lower in the LSI evaluation. The spatial distribution of the liquefaction potential of the Vs-based and SPT-based LPI assessments had a similar pattern. These results show that the LPI approach, originally SPT-based, can also be calculated based on Vs. In addition, according to Vs30-based (average shear wave velocity at 30 m depth) soil classification criteria, low-velocity character E and D soil groups dominate the Quaternary alluvial basin. This indicates that deformation-induced failures may occur even in areas with a low probability of liquefaction in similar strong ground motions. In addition, the evaluation of liquefaction with many approaches in two different bases within the scope of the study constitutes a novelty for the study area and liquefaction analyses. While performing diversified liquefaction analyses and approaches will contribute to obtaining more reliable soil liquefaction results, more case studies are needed to elucidate these comparisons.

Improved IDW Interpolation Application Using 3D Search Neighborhoods: Borehole Data-Based Seismic Liquefaction Hazard Assessment and Mapping

Traditional inverse distance weighting (IDW) interpolation is a process employed to estimate unknown values based on neighborhoods in 2D space. Proposed in this study is an improved IDW interpolation method that uses 3D search neighborhoods for effective interpolation on vertically connected observation data, such as water level, depth, and altitude. Borehole data are the data collected by subsurface boring activities and exhibit heterogeneous spatial distribution as they are densely populated near civil engineering or construction sites. In addition, they are 3D spatial data that show different subsurface characteristics by depth. The subsurface characteristics observed as such are used as core data in spatial modeling in fields, such as geology modeling, estimation of groundwater table distribution, global warming assessment, and seismic liquefaction assessment, among others. Therefore, this study proposed a seismic liquefaction assessment and mapping workflow using an improved IDW application by combining geographic information system (GIS) (ArcGIS (Esri, Redlands, CA, USA)), NURBS-based 3D CAD system (Rhino/Grasshopper (Robert McNeel & Associates, Seattle, WA, USA)), and numerical analysis system (MATLAB (MathWorks, Natick, MA, USA)). The 3D neighborhood search was conducted by the B-rep-based 3D topology analysis, and the mapping was done under the 2.5D environment by combining the voxel layer, DEM, and aerial images. The experiment was performed by collecting data in Songpa-gu, Seoul, which has the highest population density among the OECD countries. The results of the experiment showed between 7 and 105 areas with liquefaction potentials according to the search distance and the method of the approach. Finally, this study improved users’ accessibility to interpolation results by producing a 3D web app that used REST API based on OGC I3S Standards. Such an approach can be applied effectively in spatial modeling that uses 3D observation data, and in the future, it can contribute to the expansion of 3D GIS application.

Probabilistic assessment of the earthquake-induced soil liquefaction hazard at national scale: macrozonation of the Italian territory

Probabilistic assessment of the earthquake-induced soil liquefaction hazard at national scale: macrozonation of the Italian territory

Earthquake-induced liquefaction hazard mapping at national-scale in Australia using deep learning techniques

Australia is a relatively stable continental region but not tectonically inert, having geological conditions that are susceptible to liquefaction when subjected to earthquake ground motion. Liquefaction hazard assessment for Australia was conducted because no Australian liquefaction maps that are based on modern AI techniques are currently available. In this study, several conditioning factors including Shear wave velocity (Vs30), clay content, soil water content, soil bulk density, soil thickness, soil pH, distance from river, slope and elevation were considered to estimate the liquefaction potential index (LPI). By considering the Probabilistic Seismic Hazard Assessment (PSHA) technique, peak ground acceleration (PGA) was derived for 50 yrs period (500 and 2500 yrs return period) in Australia. Firstly, liquefaction hazard index (LHI) (effects based on the size and depth of the liquefiable areas) was estimated by considering the LPI along with the 2% and 10% exceedance probability of earthquake hazard. Secondly, ground acceleration data from the Geoscience Australia projecting 2% and 10% exceedance rate of PGA for 50 yrs were used in this study to produce earthquake induced soil liquefaction hazard maps. Thirdly, deep neural networks (DNNs) were also exerted to estimate liquefaction hazard that can be reported as liquefaction hazard base maps for Australia with an accuracy of 94% and 93%, respectively. As per the results, very-high liquefaction hazard can be observed in Western and Southern Australia including some parts of Victoria. This research is the first ever country-scale study to be considered for soil liquefaction hazard in Australia using geospatial information in association with PSHA and deep learning techniques. This study used an earthquake design magnitude threshold of Mw 6 using the source model characterization. The resulting maps present the earthquake-triggered liquefaction hazard and are intending to establish a conceptual structure to guide more detailed investigations as may be required in the future. The limitations of deep learning models are complex and require huge data, knowledge on topology, parameters, and training method whereas PSHA follows few assumptions. The advantages deal with the reusability of model codes and its transferability to other similar study areas. This research aims to support stakeholders’ on decision making for infrastructure investment, emergency planning and prioritisation of post-earthquake reconstruction projects.

Liquefaction hazard assessment in a seismically active region of Himalayas using geotechnical and geophysical investigations: a case study of the Jammu Region

The Jammu Region (JR) in the northwestern Himalayas trigged by medium to high magnitude near-field as well as far-field earthquake events, including the most recent 2019 Mirpur earthquake. In this paper, an attempt has been made to develop the zonation map for liquefaction hazard in the JR based on liquefaction potential index (mathrm{LPI}) and probability of liquefaction ({P}_{L}). To achieve this, factor of safety against liquefaction was estimated using standard penetration test (SPT) data collected from geotechnical consultancies and shear wave velocity measured during field testing at 243 locations, and an integrated liquefaction hazard map generated. The liquefaction features such as sand blows and ground rupture were found in Jatah (Samba district) and Simbal (Jammu district). According to the integrated hazard map, places near the bank of Tawi River and Ravi River in Jammu have young alluvium, making them particularly prone to liquefaction. Liquefaction does not occur in the eastern and western sections because of high shear wave velocities and rock at shallow depth, and it also does not occur in the central area due to thick sand deposits. mathrm{LPI} values ranged from 0 to 27.45 having very low to very high liquefaction risk. {P}_{L} is greater than 0.75 for sites located on the southwestern side due to uniformly graded soil having extremely low SPT (N) and {V}_{s} values. This study will aid site planners in the construction of structures that consider liquefaction mitigation and well-defined liquefaction risk measures.

Liquefaction hazard assessment and ground failure probability analysis in the Kathmandu Valley of Nepal

During the 2015 Gorkha Earthquake (Mw7.8), extensive soil liquefaction was observed across the Kathmandu Valley. As a densely populated urban settlement, the assessment of liquefaction potential of the valley is crucial especially for ensuring the safety of engineering structures. In this study, we use borehole data including SPT-N values of 410 locations in the valley to assess the susceptibility, hazard, and risk of liquefaction of the valley soil considering three likely-to-recur scenario earthquakes. Some of the existing and frequently used analysis and computation methods are employed for the assessments, and the obtained results are presented in the form of liquefaction hazard maps indicating factor of safety, liquefaction potential index, and probability of ground failure (PG). The assessment results reveal that most of the areas have medium to very high liquefaction susceptibility, and that the central and southern parts of the valley are more susceptible to liquefaction and are at greater risk of liquefaction damage than the northern parts. The assessment outcomes are validated with the field manifestations during the 2015 Gorkha Earthquake. The target SPT-N values (Nimproved) at potentially liquefiable areas are determined using back analysis to ascertain no liquefaction during the aforesaid three scenario earthquakes.

Assessment of soils liquefaction hazard on the Marchica lagoon zone, NE of Morocco

Liquefaction is a natural phenomenon that can occur in seismically active areas where the water table is shallower. This phenomenon mainly affects sandy soils rather than clayey soils. The assessment of the susceptibility to liquefaction is made on the basis of Kramer's four criteria. In addition, to evaluate the risk of liquefaction, we used the cyclic stress method, which is based on the comparison of the soil resistance to liquefaction (Cyclic Resistance Ratio, CRR) and the cyclic stress ratio (CSR) generated by the earthquake. A correlation between the Menard Pressuremeter Test and the Standard Penetration Test (SPT) is used to estimate CRR. Sand is the soil most sensitive to liquefaction due to its permeability and low cohesion. The result of the application of the cyclic stress method shows that the liquefaction potential is absent; this result is due to the consolidation of the sand at depth. The results of this work will alert the Marchica lagoon agency development to the imminent risk of liquefaction that will occur after the construction of infrastructure and buildings in the touristic project lands so-called “The city of two seas”.

Probabilistic framework for regional loss assessment due to earthquake-induced liquefaction including epistemic uncertainty

For seismic risk assessments, ground shaking is generally considered the primary cause of building damage. However, earthquake-induced liquefaction can also create significant structural damage and losses. Predicting the expected degree of damage in structures exposed to ground failure due to liquefaction is thus essential for seismic risk assessment. There are well-established tools and methods to evaluate the seismic risk due to ground shaking. However, despite the large number of studies related to liquefaction assessments, modelling ground failure due to an earthquake is far less mature. The incorporation of liquefaction into a seismic loss estimation framework presents several challenges. The use of simplified procedures requires a multitude of assumptions, which increase the uncertainty in the loss assessment, whilst detailed approaches based on in-situ data are resource-demanding and impractical for large-scale risk analysis. To address these shortcomings, a fully probabilistic hazard and risk assessment due to liquefaction has been employed using the OpenQuake-engine and demonstrated through a case study applied to mainland Portugal. The liquefaction hazard and risk assessment framework followed in this study allows for the incorporation of both aleatory and epistemic uncertainties, which are herein explored through a sensitivity analysis.

Technical guidelines for the assessment of earthquake induced liquefaction hazard at urban scale

Microzonation for earthquake-induced liquefaction hazard is the subdivision of a territory at a municipal or submunicipal scale in areas characterized by the same probability of liquefaction manifestation for the occurrence of an earthquake of specified intensity. The liquefaction hazard at a site depends on the severity of expected ground shaking as well as on the susceptibility to liquefaction of that site. This in turn depends on geological, geomorphological, hydrogeological and geotechnical predisposing factors. Thus, liquefaction hazard implies the existence of territories characterized by a moderate to high level of intensity of expected ground shaking. Microzonation charts for ground shaking and liquefaction hazard play a key role for the mitigation of seismic risk of an urban centre as they provide a valuable tool for the implementation of prevention strategies and land use planning. The LIQUEFACT project fully addressed the problem of microzoning a territory for earthquake-induced liquefaction hazard in a specific work package. Four municipal testing areas were selected across Europe as peculiar case studies where to construct microzonation charts for earthquake-induced liquefaction hazard. They are located in Emilia-Romagna region (Italy), Lisbon metropolitan area (Portugal), Brežice territory (Slovenia) and Marmara region (Turkey). Their location was identified based on the following criteria: severity of expected seismic hazard, availability of geological and geotechnical data, presence of liquefiable soil deposits, documented cases of liquefaction manifestations occurred in historical earthquakes, representativeness of different geological settings, density of population in selected areas (exposure). This paper illustrates the general procedure developed in LIQUEFACT for the assessment of earthquake-induced liquefaction hazard at urban scale and presents the main achievements of the microzonation studies carried out at the four previously mentioned European testbeds. Since the microzonation studies have been carried out using a shared framework and methodology, this paper has the ambition to serve as technical guidelines for updating the standards and the operational criteria currently used in different countries worldwide to construct seismic microzonation maps of liquefaction hazard.

Wave-induced liquefaction hazard assessment and liquefaction depth distribution: A case study in the Yellow River Estuary, China

Predicting the potential depth of wave-induced liquefaction is of vital importance of hazard assessment. Prevention and mitigation of liquefaction hazard can be carried out after predicting the liquefaction potential depth. Sediment geotechnical parameters were summarized from historical engineering projects and calculated liquefaction depth with data of actually measured water depth, sediment types and different wave recurrence periods. Then the study area was divided into different liquefaction zones. Results showed that both liquefaction range and depth increased with wave return period, which remained steady when increased to a certain extent. The calculated liquefaction depth was compared with the thickness of liquefied layers, which obtained by geophysical methods. Result shows that the average difference was about 1m, which means the method of liquefaction depth calculation was applicable in this study area. At last, in order to reduce harm of liquefaction, potential maximum liquefaction depth (PMLD) is put forward. PMLD is the smaller one between the thickness of seabed liquefiable sediment and the maximum calculated liquefaction depth. The calculation and partition of liquefaction depth can be more accurate after considering PMLD.

Characterization and Liquefaction Hazard Assessment of Two Hungarian Liquefied Sites from the 1956 Dunaharaszti Earthquake

The seismicity of Hungary can be considered moderately active, nevertheless contemporary reports from the past approx. 350 years documented surface manifestations of liquefaction occurrences. The last such earthquake was the 1956 Dunaharaszti ground motion, for which the location of two liquefied sites could be identified approx. 60 years after the event. This provided an excellent opportunity to analyze possibly the only accessible liquefied sites in Hungary. Analysis of the two sites included field and laboratory tests allowing the back-calculation of maximum horizontal ground acceleration of the earthquake. This parameter was previously unknown because the closest seismometer saturated during the event. The performed back-analysis using the principles of paleoliquefaction studies was the first of such analyses in the country. In areas with low to moderate seismicity, geotechnical engineers often neglect and overlook liquefaction hazard, however, when it is addressed, the hazard is often overestimated due to improper characterization of the seismic loading and site characterization. To explore this observation more deeply, probabilistic seismic and liquefaction hazard assessment were carried out at the two liquefied sites and it was found that this conclusion is also valid for Hungary, but the degree of conservatism of the pseudo-probabilistic procedures decreases with increasing earthquake return period (lower annual probability of occurrence).

Implementation and Use of a Mechanical Cone Penetration Test Database for Liquefaction Hazard Assessment of the Coastal Area of the Tuscany Region

This paper describes the implementation and use of a mechanical cone penetration test (CPTm) database for the evaluation of the liquefaction potential in some areas of Tuscany. More specifically, the database contains 4500 CPTm covering an area of 1787 square km and mainly concerns some coastal areas of Tuscany. Available simplified liquefaction evaluation procedures (LEPs) are mainly based on piezocone CPT (CPTu) test results and not on CPTm. An early interest on developing LEPs with reference to CPTm became quite soon obsolete because of the widespread use of piezocone. Unfortunately, in Italy, the use of CPTm is very popular. After the 2012 seismic sequence of Emilia-Romagna, the use of CPTm for liquefaction risk analysis has seen a renewed interest, even though such a topic should require further studies. This paper shows an empirical approach for liquefaction triggering assessment by CPTm using existing LEPs, thus making possible the use of the developed CPTm database for the preliminary screening of the study area.

Probabilistic Modelling for Earthquake Forecasting in the Northwestern Part of Haryana State, India

This study attempts to estimate the probability of the occurrence of large earthquakes (Mw ≥ 5.5) in the northwestern part of Haryana state, India, where a new nuclear power plant (NPP) is going to be constructed in the near future. First, an earthquake catalogue is developed for the period 1803–1986, and five stochastic models, namely lognormal, Weibull, gamma, Rayleigh, and double exponential, are then applied to past earthquake data. The performance of these models is checked using three statistical tests, and the lognormal, Weibull, and Rayleigh models are found to produce good approximations for this region, whereas the double exponential and gamma models yield intermediate and poor results. Hence, cumulative and conditional probabilities and related hazard curves for future earthquakes are estimated using the most suitable models. The cumulative probability of the occurrence of an earthquake (Mw ≥ 5.5) since the last event (1986) reached 0.95–0.98 as of 2018. The conditional probability of the occurrence of such an earthquake reaches 0.90–0.95 about 9–12 years from now (2027–2030), when the elapsed time will be 32 years (i.e., since 2018). The probability of earthquakes with different threshold magnitudes is then estimated, and based on the outcome of this investigation, earthquake magnitudes are classified from occasional (Mw ≤ 6.1) to very rare events (Mw ≥ 7.6) that this region may experience in the future. The findings of this study will be considered in seismic hazard assessment, liquefaction hazard assessment, and earthquake-resistant design of NPP components.

Probabilistic seismic liquefaction hazard assessment of Kathmandu valley, Nepal

Earthquakes are frequent in the Himalayas and almost all moderate to strong earthquakes have caused enormous losses of lives and property in Kathmandu Valley, Nepal. Several historical earthquakes depicted that considerable loss was attributed to liquefaction induced failure in structures and infrastructures. Existing liquefaction studies have mostly used deterministic approach to obtain the factor of safety against liquefaction. Thus, to update the conventional deterministic liquefaction analysis results, this study performs probabilistic seismic liquefaction hazard assessment of Kathmandu valley considering wide range of earthquake magnitudes and four return periods: 73, 475, 2475, and 5000 years. Liquefaction probabilities for 88 locations across Kathmandu Valley are estimated and compared with the historical occurrence to validate the results. The liquefaction hazard maps for all four return periods are prepared for all the earthquake magnitudes for 1.5 m, 3 m, 4.5 m, and 6 m depths. The sum of findings highlights that the central valley, and eastern and western fringes have higher liquefaction probabilities than the other parts.

Applicability of Pseudoprobabilistic Method of Liquefaction Hazard Assessment for Nuclear Power Plants at Diffuse Seismicity Sites

For the new nuclear power plants, the hazard of liquefaction due to earthquakes should be excluded by appropriate site selection or eliminated by engineering measures. An important question is how to define a quantitative criterion for negligibility of the liquefaction hazard. In the case of operating plants, liquefaction can be revealed as a beyond-design-basis event. It is important to learn whether the liquefaction hazard has a safety relevance and whether there is a sufficient margin to the onset of liquefaction. The use of pseudoprobabilistic method would be practicable for the definition of probability of liquefaction, but it could result in overconservative results. In this paper, the applicability of the pseudoprobabilistic procedure is demonstrated for the sites in diffuse seismicity environment and for low hazard levels that are typical for nuclear safety considerations. Use of the procedure is demonstrated in a case study with realistic site-plant parameters.