Surabaya earthquake hazard soil assessment (original) (raw)
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GIS-Based Soil Liquefaction Hazard Zonation due to Earthquake Using Geotechnical Data
International Journal of Geomate, 2012
Liquefaction is an earthquake ground failure mechanism that occurs in loose, saturated granular sediments and has caused extensive damage to the ground. Liquefaction potential zoning is the process of estimating the response of soil layers under earthquake excitations. Ground conditions play important roles in the prediction of hazards caused by earthquake. Thus to evaluate seismic hazards for a wide area, ground formation history along with soil properties must be known. This paper describes the ground conditions and behavior of Satte city as a result of Earthquake. In this paper, Geographical Information System (GIS) is used to obtain soil liquefaction hazard map. Spatial variations of soil properties are estimated from the available borehole locations where SPT-N values, water table depth and grain size distribution are known. These maps can be useful for assessing the approximate areas affected by hazards and for disaster prevention planning.
Seismic Response of Soils a Case Study of Site Specific Ground Response Analysis
civil.iisc.ernet.in
This paper presents the recent work carried out at Indian Institute of Science in the area of soil dynamics and earthquake geotechnical engineering. In the first part of the paper, a summary of work carried out on dynamic properties of Indian soils, liquefaction of sandy soils, pore pressure response in sandy soils subjected to cyclic loads is presented. The cyclic triaxial experiments on liquefiable sands from Bhuj, Ahmedabad and Assam regions have been carried out and the summary results are presented here. These regions experienced large scale liquefaction and site effects have been noticed during recent earthquakes. The data obtained for Bhuj, Ahmedabad and Assam sands, alightly deviate from the best-fit line in the plot of shear strain vs. number of cycles for initial liquefaction. The results fall closer to lower bound indicating lower cyclic strength of these sands for a given number of cycles for initial liquefaction when compared to global data. The dynamic properties such as shear modulus and damping ratios have been evaluated and summarised in this paper. In the second part of the paper, a case study of Bangalore where in site specific ground response analysis has been carried out based on large amount of SPT. Site amplification and microzonation maps of PGA at rock level and ground level have been developed and presented for Bangalore region. The study concludes that the Bangalore soils are moderately amplifying in nature and period of soil column varied from 0.08 to 4.5 seconds due to presence of silty sand and filled up soils.
Evaluation of seismic soil-liquefaction at Guwahati city
Environmental Earth Sciences, 2009
Great earthquakes in the past (e.g. 1869 Cachar earthquake, 1897 great Assam earthquake) have caused large scale damage and ground liquefaction in the Guwahati city. Moreover, seismologists are of opinion that a great earthquake might occur in the unruptured segment of the North-East Himalaya that is near to Guwahati city. In this paper, the liquefaction hazard due to these events have been simulated. The obtained results are in general agreement with the reported damages due to the past earthquakes. The central part of the city (i.e. Dispur, GS road), that has large thickness of soft soil deposit and shallow ground water table, is highly vulnerable to liquefaction.
Soil classification in a seismically active environment based on join analysis of seismic parameters
Global Journal of Environmental Science and Management, 2021
BACKGROUND AND OBJECTIVES: Soil or rock properties where buildings are situated play an important role in the ground shaking caused by an earthquake. The highly populated Banda Aceh city in the northernmost Sumatra is flanked by two active faults, the Seulimeum and the Aceh segment. Therefore, it is crucial to investigate the subsurface characteristics of the region to reduce the earthquake risk as there was no regional study has been conducted so far. METHODS: Characteristics of the soil or rock of the subsurface were derived from various seismic parameters. The seismic microtremors were recorded at 36 sites covering the highly populated city and the two active faults. The spatial autocorrelation method was used to obtain a dispersion curve based on the relationship between seismic frequencies and phase velocity from triangular geophones array to determine the shear wave velocity of the subsurface layer. The seismic amplification, dominant frequency and vulnerability value at each measurement point were measured using the horizontal-to-vertical spectral ratio method. The maps of velocity structure and HVSR parameters were generated from the interpolation of those seismic parameters. FINDINGS: Based on the variation of the four geophysical parameters: shear wave velocity, seismic amplification, dominant frequency, and seismic vulnerability, the study area can be clustered into five different groups: I) Banda Aceh, II) Jantho, III) Krueng Raya, IV) Lhoknga-Lhoong, and V) Seulawah, which classify the different types of rocks. The classification of soil properties from the combination of shear wave and horizontal-to-vertical spectral ratio data correlates with the geology of the study area. CONCLUSION: The Banda Aceh city, flanked by the two active faults, is characterized by low shear wave velocity and high amplification because the city stands on the sedimentary basin; thus, it requires a detailed investigation prior to constructing infrastructures. The other clusters are located on the relatively less vulnerable areas, indicated by moderate shear wave velocity and moderate to low seismic vulnerability indexes. The joint analysis shows that the combination of physical properties, including the shear wave velocity, seismic amplification, and dominant frequency, can be used to investigate lithology and seismic vulnerability into a specific cluster. The research results are essential for hazard mitigation and can be used for disaster risk management by the local government. A detailed investigation with denser measurement points needs to be conducted to comprehensively describe the types of rocks in Banda Aceh and its surrounding.
Assessment of soil liquefaction potential: a case study for Moulvibazar town, Sylhet, Bangladesh
SN Applied Sciences, 2020
Liquefaction can intensify the destruction caused by an earthquake; thus, a region with high liquefaction potential could be more disastrous. Bangladesh is surrounded by the Indo-Burma Folded Belt in the east, the Dauki Fault and Himalayan Syntaxis in the north that are known to have occurred high magnitude earthquakes (e.g., M w > 7) in the past. Therefore, assessing seismic hazards in the regions that are economically growing fast is of great interest. Among many other hazard assessment parameters, soil liquefaction potential index (LPI) can be used to assess seismic hazards. In this study, we have assessed the seismic hazard potential for a small town (Moulvibazar) in the northeast Bangladesh documenting liquefaction potential indices for different surface geological units using an earthquake of moment magnitude M w 8 having a peak horizontal ground acceleration (PGA) of 0.36 g. Twenty-five standard penetration test (SPT) boreholes were completed within the study area to obtain SPT-N values for two surface geological units: (1) Holo-Pleistocene low elevated terrace deposits (Zone 1) and (2) Holocene flood plain deposits (Zone 2). Using the SPT-N values, the LPI values have been calculated for the soil profile of each borehole. The LPI values in the town vary from 0 to 42.33, whereas values from 1.42 to 7.52 are in Zone 1 and values from 0 to 42.34 are in Zone 2. It has been predicted that 42% and 78% areas of Zone 1 and Zone 2, respectively, might exhibit surface manifestation of liquefaction. The results of this study can be used for seismic risk management of Moulvibazar town.
2018
throughout a large earthquake may damage or cause failure of engineered constructions. Southeast Asia is an area of mutable seismic threat, fluctuating from high seismic threat related to the subduction procedure underneath the Indonesian and Philippine archipelagos to reasonably low risk of seismic behaviour through a large steady area surrounding Malaysian peninsula. Earthquake site response analysis has been the most important and challenging task in computerizing the earthquake time history. Earthquake ground response analysis is to predict ground motion on the surface, to develop the seismic microzonation maps and also design spectral response. An Earthquake ground response analysis contains several steps in order to achieve the main result which is the response spectra. The objectives of this study are to develop a site response program code considering the local soil dynamics and the Newmark method. The result obtained from this new program code is used to prepare seismic mic...
EVALUATION OF LIQUEFACTION POTENTIAL OF BAGHDAD SOIL DURING EARTHQUAKES
This paper is concerned with the evaluation of Baghdad soil liquefaction potential under earthquakes effect. Data of soil investigation reports such as borehole total depth, water table level, total unit weight, standard penetration number and fines percentage were used. Data for 630 boreholes represent 200 site location points for many different types of projects spread all over the city have been chosen and analyzed using LiquefyPro software. Two user factors of safety and two options for fines correction have been used. Six earthquake magnitudes (M=4 to 6.5 with 0.5 interval) have been chosen to analyze the data. Only 121 points show susceptibility to liquefaction. The final output is shown in tables and the points are shown on GIS maps. The results state that the effects of earthquake induced liquefaction should be taken in consideration in future design.
GIS – based evaluation of the effect of local soil properties on the earthquake damage patterns
SAÜ Fen Bilimleri Enstitüsü Dergisi, 2016
Moderate magnitude earthquakes hit the Sakarya region, Turkey, in the range of 10-30 years. The 1999 earthquakes, which occurred in the study area, gave different damage patterns due to the variation of soil properties. In-situ and laboratory investigations were performed by Sakarya University in the centres of two townships in the Sakarya region: Arifiye and Geyve, which are known to possess different soil properties. Borings and cone penetration soundings were performed around the selected towns and data were entered into a database, which is connected to a Geographical Information System (GIS) software. Some thematic maps have been prepared for depths up to 15 m and an evaluation of damage patterns has been performed from points of view including: geology, geomorphology and geotechnical engineering in the investigation area. By evaluating the maps prepared in GIS, local soil properties affected the earthquake destruction of buildings. The number of heavily damaged buildings decreased with increasing bearing capacity. It was also proven that the liquefaction phonomena has not occurred in clayey areas.
Soil liquefaction induced settlements with interaction of earthquake hazard analysis
on the Asian side with an uninterrupted, modern, high-capacity commuter rail system. Railway tracks in both sides of Istanbul Strait will be connected to each other through a railway tunnel connection under the Istanbul Strait. The line goes underground at Yedikule, continues through the Yenikapi and Sirkeci new underground stations, passes under the Istanbul Strait, connects to the Üsküdar new underground station and emerges at Sögütlüçesme. This project is one of the major transportation infrastructure projects in the world at present. The entire upgraded and new railway system will be approximately 76 km long. In this study, by using CPT data and acceleration and magnitude data (obtained seismic hazard analysis of Marmara Region), settlement analysis were carried out for Marmaray Project. As it is known, liquefaction is a soil behavior of saturated sandy soils under the earthquake/dynamic effects. In the first phase of the study, 'cyclic stress ratio approach' was applied to all data to analysis of soil liquefaction. In the second phase of the study, by using Isihara and Yoshimine (1992) approach, possible soil settlements for several design earthquakes (for several acceleration and magnitude values) were estimated.
2018
This study aims at evaluation of seismic soil liquefaction hazard potential at Probashi Palli Abasan Project area of Tongi, Gazipur, exploiting standard penetration test (SPT) data of 15 boreholes, following Simplified Procedure. Liquefaction potential index (LPI) of each borehole was determined and then cumulative frequency distribution of clustered LPI values of each surface geology unit was determined assuming cumulative frequency at LPI = 5 as the threshold value for liquefaction initiation. By means of geotechnical investigation two surface geological units—Holocene flood plain deposits, and Pleistocene terrace deposits were identified in the study area. We predicted that 14% and 24% area of zones topped by Pleistocene terrace deposits and zones topped by Holocene flood plain deposits, respectively, would exhibit surface manifestation of liquefaction as a result of 7 magnitude earthquake. The engendered hazard map also depicts site specific liquefaction intensity through LPI values of respective boreholes, and color index, which was delineated by mapping with ArcGIS software. Very low to low, and low to high liquefaction potential, respectively, was found in the areas covered by Pleistocene terrace deposits and Holocene flood plain deposits. LPI values of both units are such that sand boils could be generated where LPI > 5.