Liquefaction Hazard Maps Research Articles

Mapping of liquefaction risk on road network based on relationship between liquefaction potential and liquefaction-induced road subsidence

On March 11, 2011, a large earthquake of Mw 9.0 shook north-eastern Japan and caused severe liquefaction-induced damage over a wide area of reclaimed lands along the coast of Tokyo Bay. Although regional mapping of the liquefaction hazard had been performed in many automounts bodies in Japan, it seems that the maps were not effectively used on all fronts of disaster-prevention management, because the maps only provide liquefaction susceptibilities and little quantitative information on how seriously the ground might deform in a scenario earthquake, which is absolutely necessary information for discussing what-if scenarios. Konagai et al. (2013) conducted air-borne LiDAR surveys to obtain liquefaction-induced ground deformations over the north-eastern stretch of the Tokyo Bay shore area, including Urayasu City, where approximately 85% of the city area was heavily liquefied. Meanwhile, the authors have developed a geotechnical database for liquefaction risk assessments, compiling all the available borehole logs and soil testing data provided by Urayasu City (2012). Given the potential risk of re-liquefaction in a future scenario earthquake, it is an overriding priority to develop a knowledge-sharing liquefaction hazard map reflecting precise records from the past, such as liquefaction-induced ground subsidence and liquefaction-related damage. This paper attempts to assess the liquefaction-induced damage risk on road network, examining the relationship between the liquefaction potential index and the actual ground subsidence. For this purpose, firstly, the spatial distribution of the liquefaction potential (PL) was estimated over Urayasu City based on the above-mentioned geotechnical database developed by the authors. Secondly, the spatial distribution of the PL values and the actual liquefaction-induced road subsidence confirmed through air-born LiDAR surveys were compared to develop an empirical rule for estimating the potential road subsidence in a scenario earthquake. This empirical rule was found to describe the actual damage to roads and manholes in a satisfactory manner. Therefore, it is expected that a risk map, developed on the basis of this empirical rule, will not only help to assess liquefaction-induced damage, but also to design countermeasures against the what-if scenarios of liquefaction.

Estimation of liquefaction potential in Eco-Delta City (Busan) using different approaches with effect of fines content

Soil liquefaction which is a disastrous phenomenon induced by the earthquake, is widely investigated in many researches in geotechnical engineering. In this study, a SPT-N based investigation is carried out to assess the susceptibility of liquefaction in Eco-Delta city, located in the southwestern part of Busan city in South Korea. Data from 229 sites are analyzed for the earthquake of 7.5 magnitude with a peak horizontal acceleration of 0.2 g to carry out the liquefaction potential index (LPI) through two deterministic methods which have different factors of safety (FS). The liquefaction probability is investigated by the deterministic and reliability methods and the liquefaction hazard maps are generated. To observe the effect of fines content and plasticity index on the liquefaction susceptibility, three different cases are considered. It is found that among the four approaches used, Overseas Coastal Area Development Institute of Japan (OCDI) method showed more sensitivity to changes of fines content and plasticity index. The Eco-Delta city is found to be highly vulnerable to liquefaction having 91% of sites with LPI values greater than 15.

Liquefaction and Related Ground Failure from July 2019 Ridgecrest Earthquake Sequence

ABSTRACT The 2019 Ridgecrest earthquake sequence produced a 4 July M 6.5 foreshock and a 5 July M 7.1 mainshock, along with 23 events with magnitudes greater than 4.5 in the 24 hr period following the mainshock. The epicenters of the two principal events were located in the Indian Wells Valley, northwest of Searles Valley near the towns of Ridgecrest, Trona, and Argus. We describe observed liquefaction manifestations including sand boils, fissures, and lateral spreading features, as well as proximate non-ground failure zones that resulted from the sequence. Expanding upon results initially presented in a report of the Geotechnical Extreme Events Reconnaissance Association, we synthesize results of field mapping, aerial imagery, and inferences of ground deformations from Synthetic Aperture Radar-based damage proxy maps (DPMs). We document incidents of liquefaction, settlement, and lateral spreading in the Naval Air Weapons Station China Lake US military base and compare locations of these observations to pre- and postevent mapping of liquefaction hazards. We describe liquefaction and ground-failure features in Trona and Argus, which produced lateral deformations and impacts on several single-story masonry and wood frame buildings. Detailed maps showing zones with and without ground failure are provided for these towns, along with mapped ground deformations along transects. Finally, we describe incidents of massive liquefaction with related ground failures and proximate areas of similar geologic origin without ground failure in the Searles Lakebed. Observations in this region are consistent with surface change predicted by the DPM. In the same region, geospatial liquefaction hazard maps are effective at identifying broad percentages of land with liquefaction-related damage. We anticipate that data presented in this article will be useful for future liquefaction susceptibility, triggering, and consequence studies being undertaken as part of the Next Generation Liquefaction project.

LIQUEFACTION MAPPING PROCEDURE DEVELOPMENT: DENSITY AND MEAN GRAIN SIZE FORMULATIONS

The assessment of liquefaction potential is very important and is the main step in making a map of liquefaction hazard in a certain area. The assessment methods of liquefaction potential have been proposed by researchers since last eight decades. Each method is based on the purposes and completeness of the data obtained by the developer. In this study, these methods then were modified to propose the new method that is easier and technically cheaper. Furthermore, the method will be applied in making liquefaction hazard maps. The method as a result of this study is a new procedure that is more practical to be applied. This method is associated with soil parameters that are commonly and easy obtained in general soil investigation. The soil parameters used to assess the potential of liquefaction in this procedure are the density and mean size of soil particles. Soil density and particle mean size needed for analysis of liquefaction potential can be obtained from laboratory tests or the correlation results from the value of field tests, namely the standard penetration test or cone penetration test. This new procedure is expected to be more applicable and reliable in making liquefaction hazard maps.

Regional efficacy of a global geospatial liquefaction model

Liquefaction hazard maps are important for both pre- and post-event planning and mitigation. The global geospatial liquefaction model (GGLM) proposed by Zhu et al. (2017) and recommended for global application results in a liquefaction probability that can be interpreted as liquefaction spatial extent (LSE). The GGLM uses ShakeMap's PGV, topography-based Vs30, distance to water body, water table depth, and annual precipitation as explanatory variables. The GGLM was originally developed and validated across 23 global earthquakes with most of the earthquakes in coastal settings. In this paper, LSE maps have been generated for 29 earthquakes around the world in a wide range of settings in addition to 23 of the original events to evaluate the generality and regional efficacy of the model. The GGLM was found to overpredict liquefaction spatial extent for earthquakes with large areas experiencing low PGA (below 0.1 g) and as a result, the GGLM has been modified to decrease over-prediction with the addition of a PGA threshold (no liquefaction when PGA < 0.1 g). The liquefaction intensity index (LII) is generated for each earthquake through the summation of LSE values across the event and compared with the liquefaction intensity inferred from the reconnaissance report. Using the LII as an indication of goodness of fit, the GGLM performs well across all regions with 5 earthquakes showing underprediction of LII and 4 earthquakes showing overprediction. When annual precipitation of a region exceeds 1700 mm, which is the upper quartile of annual precipitation in the development database, overprediction of liquefaction spatial extent is likely, and the use of threshold is recommended.

Land Damage Mapping and Liquefaction Potential Analysis of Soils from the Epicentral Region of 2017 Pohang Mw 5.4 Earthquake, South Korea

Studies on earthquake-induced liquefaction and identification of source unit for causing liquefaction have been a major concern in sustainable land use development especially in low to moderate seismic areas. During the 2017 Mw 5.4 Pohang earthquake, widespread liquefaction was reported around the Heunghae basin, which was the first ever reported case of liquefaction in the modern seismic history of Korea. The epicentral area is one of the major industrial hubs along the SE Korean Peninsula with no detailed liquefaction hazard map. The purpose of this study was to determine the land damage classification on the basis of surface manifestation of liquefaction features and carry out detailed liquefaction potential analysis to delineate the depth of liquefiable soil. This will eventually support developing a liquefaction hazard zonation map and sustainable development of infrastructure to minimize earthquake damages. In this present study, the southern part of the Heunghae basin, which has more field evidences of liquefaction than the northern part, was taken for detailed liquefaction analysis. From the detailed analysis, it was observed that the soils from 1.5 to 15 m depth with the probability of liquefaction varying from 2 to 20 are prone to liquefaction. On the basis of land damage pattern, the epicentral area falls in orange to red zone, which means the necessity of further detailed liquefaction analysis. This study urges more detailed liquefaction zonation should be carried out for the epicentral area and liquefaction hazard should be included in the multi-hazard map in the future for the sustainable land use planning.

A Geotechnical Database for Utah (GeoDU) enabling quantification of geotechnical properties of surficial geologic units for geohazard assessments

Geotechnical borehole information is often used for liquefaction hazard mapping, but can be highly variable in terms of quantity and quality. In addition, geotechnical borehole logs are often provided as images in reports rather than delivered in a structured, queryable database, which makes the logs and supplementary information difficult to organize particularly across a large geographic area. In contrast, surficial geologic mapping is generally available and often accessible in geographic information systems (GIS) format. This article’s objective is to describe the compilation of a geotechnical database for regional mapping purposes and to demonstrate the value of documenting geotechnical data into a consistent data format. Specifically, this article describes the development of three geotechnical borehole databases compiled in Utah, which has been coined the Geotechnical Database for Utah (GeoDU). The database is used to quantify geotechnical properties for subsequent liquefaction evaluations of surficial geologic units comprising similar depositional environment and age. The resulting GeoDU is an important resource for future efforts with many applications including community data sharing and planning for preliminary geotechnical site investigations.

Improvement suggestions for problems of hazard map from the viewpoint of color scheme

Abstract. Local governments often rely on hazard maps to plan for and respond to local natural disasters. These maps often rely on the use of many colors, but their exact color scheme and style differs in each area. As a result, we hypothesize that some users, specifically colorblind individuals, may have difficulty correctly understanding the information on some of these hazard maps. In this study, we test that hypothesis by conducting a survey of Japanese liquefaction hazard maps and their visual accessibility. To this end, we first undergo a survey of the color schemes used in these maps and investigate whether they are easily understood by people with colorblindness. We next specifically analyze several maps we deem particularly problematic in terms of color scheme and visibility, using these as case studies to discuss issues with accessibility and to summarize possible countermeasures. Our survey found that liquefaction hazard maps use one of three main color schemes: “diverging color scheme,” “Sequential cold colors,” or “sequential warm colors.” However, while there were issues with several maps, including difficulty reading the background map or correctly understanding the risk of liquefaction, these difficulties were not related to the color scheme used. To improve the accessibility of hazard maps, therefore, is necessary to create a unified manual that contains the following information: an examination of colors, the utilization of a universal design check tool, and the use of GIS vector data.

GIS based approach to analyze soil liquefaction and amplification: A case study in Eskisehir, Turkey

Abstract This study involves gathering the geological and geotechnical data and processing them in 3D structural model for the assessment of the likelihood of liquefaction hazard. A total of 467 borehole logs up to 30 m of depth were analyzed. Based on engineering characteristics of the soil formation, Geographical Information System based subsurface model maps and liquefaction hazard maps were prepared. Also microtremor measurements have been taken on different locations to assess the amplification of the alluvial formation. By obtaining amplification spectrum between the soil layers and response spectra at the top of the bedrock and at ground surface, a thematic map on amplification factor is produced. It is believed such kind of visual models will help engineers and designers on all aspects of future development of the cities especially transportation, infrastructure, and land uses against possible earthquake hazards.

Semi-automated landform classification for hazard mapping of soil liquefaction by earthquake

Abstract. Soil liquefaction damages were caused by huge earthquake in Japan, and the similar damages are concerned in near future huge earthquake. On the other hand, a preparation of soil liquefaction risk map (soil liquefaction hazard map) is impeded by the difficulty of evaluation of soil liquefaction risk. Generally, relative soil liquefaction risk should be able to be evaluated from landform classification data by using experimental rule based on the relationship between extent of soil liquefaction damage and landform classification items associated with past earthquake. Therefore, I rearranged the relationship between landform classification items and soil liquefaction risk intelligibly in order to enable the evaluation of soil liquefaction risk based on landform classification data appropriately and efficiently. And I developed a new method of generating landform classification data of 50-m grid size from existing landform classification data of 250-m grid size by using digital elevation model (DEM) data and multi-band satellite image data in order to evaluate soil liquefaction risk in detail spatially. It is expected that the products of this study contribute to efficient producing of soil liquefaction hazard map by local government.

Liquefaction Hazard Map Based on in Pohang Under Based on Earthquake Scenarios

The The purpose of this study is to investigate the actual liquefaction occurrence site in Pohang area and to analyze the ground characteristics of Pohang area using the data of the National Geotechnical Information DB Center and to calculate the liquefaction potential index. Based on the results, t...

Update of the Urban Seismic and Liquefaction Hazard Maps for Memphis and Shelby County, Tennessee: Liquefaction Probability Curves and 2015 Hazard Maps

Update of the Urban Seismic and Liquefaction Hazard Maps for Memphis and Shelby County, Tennessee: Liquefaction Probability Curves and 2015 Hazard Maps

Seismic Liquefaction Potential in Muscat, Sultanate of Oman

Seismic liquefaction is a serious geotechnical engineering problem that takes place in saturated cohesion less soils during earthquakes due to the increase of pore-pressure so that the soil shear strength is decreased to zero. Muscat is situated in the north-eastern part of Oman close to Oman Mountains, which witnessed four earthquakes of order of 5.2 magnitude in the last 1300 years. The surface geology of Muscat reveals great variety of hard rocks in the eastern, southern and western parts to dense and lose sediments in the middle and northern parts. Muscat Municipality provided 1082 borehole data to be examined for their liquefaction susceptibility based on the soil characteristics. Susceptible soils only are further considered to liquefaction hazard assessment. Liquefaction occurs during an earthquake if the cyclic stress ratio (CSR) caused by the earthquake is higher than the cyclic resistance ratio (CRR) of the soil. CSR values were evaluated using probabilistic peak ground acceleration (PGA) values for return period of 2475 years at the surface given by detailed hazard and micro zonation studies. CRR for Muscat region is conducted based on the borehole data with N values of SPT tests, and shear wave velocity results from 99 MASW surveys over the entire region. All the required corrections to get standardized (N1) 60 values, to correct shear-wave velocity, and scale the results for Mw 6.0 instead of the proposed 7.5 are conducted. Liquefaction hazard maps were created using the minimum factor of safety (FS) at each site as a representative of the FS against liquefaction at that location. Results indicate that under the current level of seismic hazard, liquefaction potential is possible at some sites along the northern coast, where alluvial soils, shallow ground water table, and relatively high ground motion are present. The expected settlement of the soft soil at each liquefiable site is also evaluated.

Examining the Discrepancy between Forecast and Observed Liquefaction from the 2015 Gorkha, Nepal, Earthquakes

Many ground failures resulted from the 2015 Nepal earthquake sequence, including landslides, rockfalls, liquefactions, and cyclic failures. And whereas the amount and extent of landsliding were relatively consistent with predictions for a Mw7.8 main shock, the amount and extent of liquefaction were not. We present a summary of liquefaction field observations that we made as part of the Geotechnical Extreme Events Reconnaissance (GEER) investigations. The liquefaction that did occur in the Kathmandu Valley was limited in its spatial extent, and the postliquefaction deformations were small. Prior earthquakes in this region have been reported to have caused greater liquefaction-related failures, and liquefaction hazard–mapping studies predicted widespread liquefaction hazard from an event of this size. We explore two possible reasons at the regional scale for the limited liquefaction from this earthquake sequence: drawdown of the groundwater table and high near-surface shear wave velocity. Our study finds that pumping has depressed the groundwater table across the Kathmandu Valley by 13–40 m since 1980, thereby decreasing the amount of near-surface liquefiable material and increasing the nonliquefiable “crust” layer. The regional slope-based VS30for the valley is on average higher than that for liquefaction sites in a global database of observed liquefaction. A global geospatial model for liquefaction occurrence shows low liquefaction potential in the Kathmandu Valley consistent with the observed patterns.

A hybrid geotechnical and geological data-based framework for multiscale regional liquefaction hazard mapping

Regional assessment of liquefaction hazard necessitates not only models for evaluating liquefaction potentials and their spatial extent, but also the means to account for heterogeneous sources of i...

Liquefaction hazard mapping in the city of Boumerd\xe8s, Northern Algeria

The city of Boumerdès, located in Northern Algeria, was badly affected during the May 21, 2003 Zemmouri (Mw = 6.8) earthquake where extensive liquefaction has been reported. The aim of this paper is to assess and to map the liquefaction potential for Boumerdès. We collected and used data from 154 boreholes, 10 down-hole tests, 56 standard penetrations tests (SPT), and inventory of 35 water level points. This data has been analyzed in the framework of geographical information systems (GIS). We assessed the liquefaction potential index (LPI) by considering a seismic hazard scenario corresponding to amax = 0.48 g calculated, using a probabilistic approach, for a return period of 500 years. LPI values have been correlated to compile the liquefaction hazard map that indicates the quantitative characteristics of the liquefiable layers and the induced disruption probability area. Results show that the main part of the city of Boumerdès belongs to a low liquefaction potential area except for a narrow corridor along the Corso waterway, where the liquefaction potential is moderate to high. The obtained results are compatible with the geological, geotechnical and hydrogeological susceptibility to liquefaction of the area. The results also show a good agreement with the observations made after the May 21, 2003 Zemmouri earthquake. The obtained liquefaction hazard maps may serve as useful tools for land management and planning in the city of Boumerdès and as an example of liquefaction hazard assessment that may be applied in other populated cities in northern Algeria’s seismic prone areas.

Random field-based regional liquefaction hazard mapping — data inference and model verification using a synthetic digital soil field

Geostatistical tools and random field models have been increasingly used in recent liquefaction mapping studies. However, a systematic verification and assessment of random field models has yet to be taken, and implications of various random field-based mapping approaches are unknown. In this paper, an extremely detailed three-dimensional synthetic digital soil field is artificially generated and used as a basis for assessing and verifying various random field-based models for liquefaction mapping. Liquefaction hazard is quantified in terms of the liquefaction potential index (LPI), which is mapped over the studied field. A classical CPT-based liquefaction model is adopted to assess liquefaction potential of a soil layer. Different virtual field investigation plans are designed to assess the dependency of data inference and model performance upon the level of availability of sampling data. Model performances are assessed using three information theory-based measures. Results show that when sampling data is sufficient, all random field-based models examined capture fairly well the benchmark liquefaction potentials in the studied field. As the size of the sampling data decreases, the accuracy of predictions decreases for all models but to different degrees; the three-dimensional random field model gives the best result in this scenario. All random field-based models examined in this paper yield a slightly more conservative prediction of liquefaction potential over the studied field.

St. Louis Area Earthquake Hazards Mapping Project: Seismic and Liquefaction Hazard Maps

ABSTRACT We present probabilistic and deterministic seismic and liquefaction hazard maps for the densely populated St. Louis metropolitan area that account for the expected effects of surficial geology on earthquake ground shaking. Hazard calculations were based on a map grid of 0.005°, or about every 500 m, and are thus higher in resolution than any earlier studies. To estimate ground motions at the surface of the model (e.g., site amplification), we used a new detailed near‐surface shear‐wave velocity model in a 1D equivalent‐linear response analysis. When compared with the 2014 U.S. Geological Survey (USGS) National Seismic Hazard Model, which uses a uniform firm‐rock‐site condition, the new probabilistic seismic‐hazard estimates document much more variability. Hazard levels for upland sites (consisting of bedrock and weathered bedrock overlain by loess‐covered till and drift deposits), show up to twice the ground‐motion values for peak ground acceleration (PGA), and similar ground‐motion values for 1.0 s spectral acceleration (SA). Probabilistic ground‐motion levels for lowland alluvial floodplain sites (generally the 20–40‐m‐thick modern Mississippi and Missouri River floodplain deposits overlying bedrock) exhibit up to twice the ground‐motion levels for PGA, and up to three times the ground‐motion levels for 1.0 s SA. Liquefaction probability curves were developed from available standard penetration test data assuming typical lowland and upland water table levels. A simplified liquefaction hazard map was created from the 5%‐in‐50‐year probabilistic ground‐shaking model. The liquefaction hazard ranges from low ( 60% of area expected to liquefy) in the lowlands. Because many transportation routes, power and gas transmission lines, and population centers exist in or on the highly susceptible lowland alluvium, these areas in the St. Louis region are at significant potential risk from seismically induced liquefaction and associated ground deformation.

Clarifying the differences between traditional liquefaction hazard maps and probabilistic liquefaction reference parameter maps

Traditional liquefaction hazard maps are useful tools for preliminary engineering site assessment and policy development. However, these maps should not be used for site-specific liquefaction hazard assessment. Simplified probabilistic liquefaction analysis procedures can be used instead to perform site-specific liquefaction hazard assessment, but these procedures rely on probabilistic reference parameter maps that are not yet familiar to most engineering and geological practitioners. As a result, some professionals are questioning the differences between traditional liquefaction hazard maps and the new probabilistic reference parameter maps. This paper clarifies the differences between these two types of maps, and shows how each of these maps complements the other. New probabilistic reference parameter maps for liquefaction triggering and lateral spread displacement are developed and presented for San Diego, California, and simplified probabilistic equations necessary to use the reference parameter maps are summarized. An example map-based liquefaction triggering and lateral spread displacement analysis is performed for a representative site near San Diego Bay. Results of the analysis demonstrate that the probabilistic assessment confirms and augments the information conveyed by the traditional liquefaction hazard map.

Liquefaction hazard map in Korean disaster monitoring system

Liquefaction hazard map in Korean disaster monitoring system