Microtremor recordings are time series of small amplitude ground vibrations in three orthogonal directions, aligned to vertical v, northsouth ns and eastwest ew. Figure 6 shows the transfer functions for p, s, love and rayleigh waves between depths of the surface and borehole sensors. Q quality factor values were assumed as q s v s 15. Then, we used the following formulas in waveform processing of microtremor. Pdf on aug 27, 2018, luyi shen and others published seismic characterization for underground construction projects using microtremor survey method. The microtremor survey method geophysical monograph series issue 12 of seg geophysical monograph issue 12 of society of exploration geophysicists geophysical monograph. The term ambient vibrations is now preferred to talk about this phenomenon. Evidence of 2d resonance from microtremor observations article pdf available january 2008 with 106 reads how we measure. The microtremor data was originally stored in the seg2 format. The microtremor survey method msm is flexible, noninvasive, relatively.
Microtremor survey in landslide zone of ngroto girimulyo. The seismic hazard microzonation for ground shaking site effects have been determined from 75 microtremor measurements in and around delhi, india. This method was first proposed by nogoshi and igarashi 1971 and years later it was summariz. A lowcost energyefficient cableless geophone unit for. Pdf microtremor survey methods in the tamar valley. The volumes six worldrenowned authors have updated this second edition to present newly emerging pdf approaches to survey research and provide more comprehensive coverage of the major considerations in designing and conducting a sample survey. Regarding hv spectral ratio method, peak frequency and amplification factor were calculated for all microtremor stations. Michael asten is a principal research fellow at monash university parttime, and is also a. Kristek abstract the requirement of a layeredearth geology is a restrictive assumption.
Microtremor measurement was done at eighty sites in bago city and the site locations are shown in figure 5. The method that employs microtremor is handy but has not produced satisfactory result to this day. Geophysical monograph series the microtremor survey free download as pdf file. We use the microtremor survey method to record ambient ground vibrations in launceston. Michael w asten school of geosciences monash university. This paper describes a new processing method that employs microtremor observation yet producing accurate estimation of characteristics of the ground motion. The microtremor array exploration method is a method for. The site parameter in seismic hazard calculation by using the selected gmpe is the average shear wave velocity to the upper 30 m, v s 30 and the hv spectral technique is used to calculate vs30. Both beamforming fk and spatial autocorrelation spac methods are used to process msm data. Using the spac microtremor method to identify 2d effects. This method in its original form adopted a limited number usually fewer than ten of receivers channels for data acquisition. The use of microtremor data for seismic hazard microzonation is an extremely efficient and low cost method available for seismic hazard microzonation field and jacob, 1995. A method for dynamic characteristics estimation of subsurface using microtremor on the ground surface. Application of the microtremor measurements to a site effect.
Geophysical monograph series the microtremor survey spectral. This is especially useful in areas where earthquakes are not very frequent, making it difficult to use earthquakes for microzonation. At bago city, microtremor measurement is carried out on 21 july, 20 to 27 july, 20. Observation of microtremors can give useful information on dynamic properties of the site such as predominant period and amplitude. Parvez, philippe rosset, in earthquake hazard, risk and disasters, 2014. Due to their nonintrusive nature, these methods have been incorporated into geotechnical engineering applications since the passive masw 8 and the refraction microtremor remi 9 were developed. In a detailed analysis of two representative stations of the survey we extract different seismic attributes. Alternatively, standalone seismometers can be used, but they are bulky, heavy, and expensive.
Hvsr gained prominence as a site characterization tool beginning with the work of nakamura 1989. Refraction microtremor method for delineation of layers and. John louie and others based on previously existing principles of evaluating surface waves and in particular rayleigh waves. Information and translations of microtremor in the most comprehensive dictionary definitions resource on the web. Pdf microtremor surveys at their simplest level of measurement single. Remi provides high resolution seismic shear wave velocity models up to 200m depth and as such has the potential of being an efficient method for assessing the soil liquefaction potential in sei. The microtremor survey method geoscienceworld books. The passive masw method, on the other hand, usually uses more 24 or more channels than msm and aims to fully exploit the advantages of multichannel recording and processing. However, it was found true only for the fundamental resonance peak of the transfer function. The microtremor survey method kandilli rasathanesi. Refraction microtremor remi is a relatively new method in the geophysics industry.
It also discusses factors to consider when choosing a survey. Method this study used microtremor data from 33 measurement points. Key topics in survey methodology are clearly explained in the books chapters, with coverage. The development of a new exploration method, designated the microtremor survey method msm by okada et al. The application of microtremor survey method in investigating the geological formation of singapore. Pdf shear wave velocity analysis of a deep seated gravel. Array observations of the vertical component of microtremors are frequently conducted to estimate subsurface structures as a shearwave velocity distribution in urban or environmentally sensitive areas. At the known fault trace both methods generally agree qualitatively with available subsurface data and each other. Optimised array design for microtremor array studies applied to. A key technique is the microtremor survey method okada. Jul 28, 2017 microtremor measurement is fast, applicable, costeffective. In this study, longterm recordings were split into 1520 min segments without overlap, comparable to the length of shortterm 15 min recordings. According to the analysis, the peak frequency varies from. As the other site investigation method, we conducted the microtremor surveying in taungoo and bago during 27 july, 20 as geophysical survey.
Survey research methods uf college of journalism and. Conclusions it is advised to use the masw method with suitable source and data acquisition parameters especially in near surface characterization. Regarding hv spectral ratio method, peak frequency and ampli. Combined use of spac, fk and hvsr microtremor survey methods for site hazard study over the tamar valley, launceston, tasmania. Types of survey method this module introduces different types of survey method e. Kristek abstract the requirement of a layeredearth geology is a restrictive assumption when using the spatially averaged coherency spectra spac method.
The application of microtremor survey method in investigating. In recent years, the microtremor survey method, which has two. Measurement and analysis of microtremor data has proved to be an efficient and low cost method of seismic hazard microzonation. Please use this identifier to cite or link to this item. Bedrock depth can vary by as much as 30 m over distances of 100 m. The microtremor method mtm using spatial autocorrelation spac. Microtremor measurements were taken at 15 stations in the babol, north of iran. The refraction microtremor remi method provides an effective and efficient means. Microtremor data acquisition, analysis and results 6 the bedrock beneath lower manhattan consists of late proterozoic to paleozoic metamorphic rocks that range in depth from outcropping to 55 m baskerville, 1994.
The microtremor approach can describe local geological conditions from predominant frequency. Microtremor survey methods in the tamar valley, launceston. In the earlier survey, the modal nature of the imaged dispersion trends. Imaging dispersion curves of passive surface waves choon. Flowchart of the integrated approach for masw and the microtremor survey to obtain bestfit velocity model and hv ratios after kanl. Microtremor survey methods in the tamar valley, launceston, tasmania. Microtremor survey in landslide zone of ngroto girimulyo kulonprogo yogyakarta novia nurul khayati1,a. Soil deposits defined as all unconsolidated geologic material overlying bedrock are primarily glacial units. Constructing a system to explore shallow velocity structures using a. It has been proved that measurement and analysis of microtremor data is an ef. The microtremor survey method listens to the natural seismic signals from road traffic, machinery, ocean waves, and meteorological sources and analyzes for subsurface acoustic properties, in particular the shearvelocity profile for the earth at a scale of a few meters to a few kilometers. Sep 25, 2015 the passive surface wave methods were initially developed in the 1950s as microtremor survey methods msm. This method is now widely used for microtremor observation although it lacks a clear theoretical background.
Box 118, lund, sweden abstract with a surface wave method to estimate shearwave velocity vs from dispersion curves of. It also discusses factors to consider when choosing a survey method. Fault mapping with the refraction microtremor and seismic. Results of microtremor mesurement waveform processing of microtremor first, we cut off all the acceleration time history data of microtremor into 40. Research location was in ngroto area of purwosari village, girimulyo subdistrict of kulonprogo regency. The passive surface wave survey is a practical, noninvasive seismic exploration method that has increasingly been used in geotechnical engineering. Application of the microtremor measurements to a site.
However, in situ deployment of traditional wired geophones is labor intensive for a dense sensor array. Microtremor survey method, array observation, rayleigh wave, swave velocity, soilstructure model. Multichannel analysis of surface waves maswactive and. Combined use of active and passive surface waves c. Pdf combined use of spac, fk and hvsr microtremor survey. Microtremor measurement is fast, applicable, costeffective. Pdf the depth and geometry of potential failure surface is the fundamental for. Since the data were recorded simultaneously and individually, the single channel data files of an array were. Low cost seismic microzonation using microtremor data. We describe how we extract a hydrocarbon potential map from spectral anomalies and compare this map with available reservoir location data. Pdf microtremor survey design optimized for application to site.
The author performs remi surveys using a geometrics s12 smartseis 12. Using the spac microtremor method to identify 2d effects and evaluate 1d shearwave velocity profile in valleys by m. Formerly is physics department, institut teknologi sepuluh nopember its, surabaya, indonesia 6011. Introduction 2 the spatial autocorrelation spac method aki, 1957, wherein the records from a circular array of evenly spaced sensors and a central sensor are analyzed, is one of the commonly used measurementanalysis techniques in the microtremor survey method msm okada, 2003. Microtremor survey was carried out in sagaing, taungoo and bago cities during july, 20. Shear wave velocity profile from microtremor surveys drntu. Data analysis for the spac method mainly consists of four steps. Site characterization for urban seismic hazards in lower. Refraction microtremor method for delineation of layers. The microtremor survey method geophysical monograph series. Remi method is still very new, but holds key advantages over other geophysical. Recent advances in technology lowfrequency seismic.
The microtremor data was originally stored in the mtn format. Microtremor data analysis is applied in the recognition of the soil layers, prediction of shearwave velocity of the ground, and evaluation of the predominant period of the soil during earthquake events. Lermo and chavezgarcia showed the applicability of nakamuras method of microtremor in site effect prediction. Imaging dispersion curves of passive surface waves choon park. In this method, the azimuthal average of the complex coherence functions ccfs between the. Chapter 3 principle of the microtremor survey method part 1. Direct estimation of the rayleigh wave phase velocity in. Ivanov1 1kansas geological survey, the university of kansas, lawrence, kan. Principle of the microtremor survey method part 1 the microtremor survey method hiroshi okada chapter 3 principle of the microtremor survey method 2 3. Application of microtremor hvsr method for assessing site. Dwa desa warnana is with civil engineering department, institut teknologi sepuluh nopember its, surabaya, indonesia.
According to the analysis, the peak frequency varies from 0. Railway technical research institute, quarterly reports, 301. Using this method, fundamental frequency of a site can be determined by applying the horizontaltovertical spectral ratio method nakamura, 1989. Application effectiveness of the microtremor survey method in the. Microtremor recordings in northern mississippi sciencedirect. Microtremor is a low amplitude in the order of micrometres ambient vibration of the ground caused by manmade or atmospheric disturbances. Traditional microzonation methodology based on the nakamura. The refraction microtremor technology was developed at the university of nevada and is owned by the state of nevada. Final year project report, nanyang technological university. The microtremor survey method geophysical monograph. Microtremor survey method provides an alternative tool for site exploration as it is simple, much cheaper and noninvasive.