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Bahavar, Manochehr, Zack J. Spica, Francisco J. Sánchez-Sesma, Chad Trabant, Arash Zandieh et Gabriel Toro. « Horizontal-to-Vertical Spectral Ratio (HVSR) IRIS Station Toolbox ». Seismological Research Letters 91, no 6 (19 août 2020) : 3539–49. http://dx.doi.org/10.1785/0220200047.
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Abstract The horizontal-to-vertical spectral ratio (HVSR) for seismic ambient noise is a popular method that can be used to estimate the predominant frequency at a given site. In this article, we introduce the Incorporated Research Institutions for Seismology (IRIS) Data Management Center’s (DMC’s) openly available HVSR station toolbox. These tools offer a variety of ways to compute the spectral ratio by providing different averaging routines. The options range from the simple average of spectral ratios to the ratio of spectral averages. Computations take advantage of the available power spectral density estimates of ambient noise for the seismic stations, and they can be used to estimate the predominant frequency of the many three-component seismic stations available from the IRIS DMC. Furthermore, to facilitate the identification of the peaks in HVSR profiles for the assessment of the predominant frequency of station sites, the toolbox can also process the results of HVSR analysis to detect and rank HVSR peaks. To highlight the toolbox capabilities, three different examples of possible use of this toolbox for routine site-effect analysis are discussed: (1) site effects related to thawing in Arctic regions, (2) ground-motion amplification in urban area, and (3) estimation of station VS30.
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Neukirch, Maik, Antonio García-Jerez, Antonio Villaseñor, Francisco Luzón, Mario Ruiz et Luis Molina. « Horizontal-to-Vertical Spectral Ratio of Ambient Vibration Obtained with Hilbert–Huang Transform ». Sensors 21, no 9 (10 mai 2021) : 3292. http://dx.doi.org/10.3390/s21093292.
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The Horizontal-to-Vertical Spectral Ratio (HVSR) of ambient vibration measurements is a common tool to explore near surface shear wave velocity (Vs) structure. HVSR is often applied for earthquake risk assessments and civil engineering projects. Ambient vibration signal originates from the combination of a multitude of natural and man-made sources. Ambient vibration sources can be any ground motion inducing phenomena, e.g., ocean waves, wind, industrial activity or road traffic, where each source does not need to be strictly stationary even during short times. Typically, the Fast Fourier Transform (FFT) is applied to obtain spectral information from the measured time series in order to estimate the HVSR, even though possible non-stationarity may bias the spectra and HVSR estimates. This problem can be alleviated by employing the Hilbert–Huang Transform (HHT) instead of FFT. Comparing 1D inversion results for FFT and HHT-based HVSR estimates from data measured at a well studied, urban, permanent station, we find that HHT-based inversion models may yield a lower data misfit χ2 by up to a factor of 25, a more appropriate Vs model according to available well-log lithology, and higher confidence in the achieved model.
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Mendecki, Maciej J., Barbara Bieta, Mateusz Mateuszów et Paweł Suszka. « Comparison of site effect values obtained by HVSR and HVSRN methods for single-station measurements in Tarnówek, South-Western Poland. » Contemporary Trends in Geoscience 5, no 1 (1 juin 2016) : 18–27. http://dx.doi.org/10.1515/ctg-2016-0002.
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Abstract This study compares the HVSR technique (Horizontal to Vertical Spectral Ratio), based on seismic event records, and the HVSRN technique (Horizontal to Vertical Spectral Ratio of Noise) using seismic noise registrations. Both methods allow us to study the amplification phenomenon of a horizontal component of seismic waves when the waves reach loose sediments in subsurface layers. The seismic data were measured at a three-component single seismic station located in the village of Tarnówek, in the Legnica-Głogów Copper District. The results of the study demonstrate that average HVSRN and HVSR maxima can be distinguished: for periods approximately 3.78 s (H/V = 6.2) and 3.969 s (H/V = 8.98) respectively. The evaluated share of the Rayleigh wave component in the recorded values was β = 0.58 and it can be suggested that the Love wave share in surface motion was insignificant. The Love wave share remains unknown.
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Wang, Pengfei, Paolo Zimmaro, Tristan E. Buckreis, Tatiana Gospe, Scott J. Brandenberg, Sean K. Ahdi, Alan Yong et Jonathan P. Stewart. « Relational Database for Horizontal-to-Vertical Spectral Ratios ». Seismological Research Letters 93, no 2A (29 décembre 2021) : 1075–88. http://dx.doi.org/10.1785/0220210128.
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Abstract Frequency-dependent horizontal-to-vertical spectral ratios (HVSRs) of Fourier amplitudes from three-component recordings can provide useful information for site response modeling. However, such information is not incorporated into most ground-motion models, including those from Next-Generation Attenuation projects, which instead use the time-averaged shear-wave velocity (VS) in the upper 30 m of the site and sediment depth terms. To facilitate utilization of HVSR, we developed a publicly accessible relational database. This database is adapted from a similar repository for VS data and provides microtremor-based HVSR data (mHVSR) and supporting metadata, but not parameters derived from the data. Users can interact with the data directly within a web portal that contains a graphical user interface (GUI) or through external tools that perform cloud-based computations. Within the database GUI, the median horizontal-component mHVSR can be plotted against frequency, with the mean and mean ± one standard deviation (representing variability across time windows) provided. Using external interactive tools (provided as a Jupyter Notebook and an R script), users can replot mHVSR (as in the database) or create polar plots. These tools can also derive parameters of potential interest for modeling purposes, including a binary variable indicating whether an mHVSR plot contains peaks, as well as the fitted properties of those peaks (frequencies, amplitudes, and widths). Metadata are also accessible, which includes site location, details about the instruments used to make the measurements, and data processing information related to windowing, antitrigger routines, and filtering.
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Mi, Binbin, Yue Hu, Jianghai Xia et Laura Valentina Socco. « Estimation of horizontal-to-vertical spectral ratios (ellipticity) of Rayleigh waves from multistation active-seismic records ». GEOPHYSICS 84, no 6 (1 novembre 2019) : EN81—EN92. http://dx.doi.org/10.1190/geo2018-0651.1.
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The horizontal-to-vertical spectral-ratio (HVSR) analysis of ambient noise recordings is a popular reconnaissance tool used worldwide for seismic microzonation and earthquake site characterization. We have expanded this single-station passive HVSR technique to active multicomponent data. We focus on the calculation of the HVSR of Rayleigh waves from active-seismic records. We separate different modes of Rayleigh waves in seismic dispersion spectra and then estimate the HVSR for the fundamental mode. The mode separation is implemented in the frequency-phase velocity ([Formula: see text]-[Formula: see text]) domain through the high-resolution linear Radon transformation. The estimated Rayleigh-wave HVSR curve after mode separation is consistent with the theoretical HVSR curve, which is computed by solving the Rayleigh-wave eigenproblem in the laterally homogeneous layered medium. We find that the HVSR peak and trough frequencies are very sensitive to velocity contrast and interface depth and that HVSR curves contain information on lateral velocity variations. Using synthetic and field data, we determine the validity of estimating active Rayleigh-wave HVSR after mode separation. Our approach can be a viable and more accurate alternative to the empirical HVSR analysis method and brings a novel approach for the analysis of active multicomponent seismic data.
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Pentaris, F. P. « A novel horizontal to vertical spectral ratio approach in a wired structural health monitoring system ». Journal of Sensors and Sensor Systems 3, no 2 (8 août 2014) : 145–65. http://dx.doi.org/10.5194/jsss-3-145-2014.
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Abstract. This work studies the effect ambient seismic noise can have on building constructions, in comparison with the traditional study of strong seismic motion in buildings, for the purpose of structural health monitoring. Traditionally, engineers have observed the effect of earthquakes on buildings by usage of seismometers at various levels. A new approach is proposed in which acceleration recordings of ambient seismic noise are used and horizontal to vertical spectra ratio (HVSR) process is applied, in order to determine the resonance frequency of movement due to excitation of the building from a strong seismic event. The HVSR technique is widely used by geophysicists to study the resonance frequency of sediments over bedrock, while its usage inside buildings is limited. This study applies the recordings inside two university buildings attached to each other, but with different construction materials and different years of construction. Also there is HVSR application in another much older building, with visible cracks in its structure. Sensors have been installed on every floor of the two university buildings, and recordings have been acquired both of ambient seismic noise and earthquakes. Resonance frequencies for every floor of every building are calculated, from both noise and earthquake records, using the HVSR technique for the ambient noise data and the receiver function (RF) for the earthquake data. Differential acceleration drift for every building is also calculated, and there is correlation with the vulnerability of the buildings. Results indicate that HVSR process on acceleration data proves to be an easy, fast, economical method for estimation of fundamental frequency of structures as well as an assessment method for building vulnerability estimation. Comparison between HVSR and RF technique shows an agreement at the change of resonance frequency as we move to higher floors.
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Iswanto, Eko Rudi, Yuni Indrawati et Theo Alvin Riyanto. « Studi Mikrotremor dengan Metode Horizontal to Vertical Spectral Ratio (HVSR) di Tapak RDE, Serpong ». EKSPLORIUM 40, no 2 (30 novembre 2019) : 105. http://dx.doi.org/10.17146/eksplorium.2019.40.2.5489.
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ABSTRAKBencana alam seperti kejadian gempa bumi dapat menyebabkan kerusakan pada area tapak dan infrastruktur termasuk fasilitas reaktor nuklir. Fenomena ini perlu dipahami secara komprehensif melalui catatan sejarah karakteristik dinamik tapak. Penggunaan mikrotremor dengan metode Horizontal to Vertical Spectral Ratio (HVSR) telah digunakan secara luas dalam investigasi bawah permukaan sejak satu dekade terakhir. Tujuan penelitian ini adalah mengetahui karakteristik geologi setempat dan karakteristik dinamis bawah permukaan. Penelitian ini mengaplikasikan penggunaan mikrotremor metode HVSR di tapak Reaktor Daya Eksperimental (RDE) di Serpong. Pengukuran dilakukan di 15 lokasi, kemudian data diolah dengan metode HVSR menggunakan perangkat lunak Geopsy. Hasil analisis menunjukkan bahwa Tapak RDE mempunyai nilai frekuensi dominan antara 3,06 Hz–23,27 Hz dan faktor amplifikasi 1,84–6,37. Bagian timur laut dan tenggara tapak memiliki indeks kerentanan seismik yang lebih tinggi dibandingkan dengan bagian lainnya. Oleh karena itu, pilihan lokasi gedung reaktor di area barat daya sudah tepat kerena memiliki faktor amplifikasi, ketebalan sedimen, dan indeks kerentanan seismik yang relatif rendah.ABSTRACTNatural disaster like earthquake can cause damage to the site and the infrastructure including nuclear reactor facilities. This phenomenon needs comprehensively understood through its dynamic characteristics historical records of the site. The use of Horizontal to Vertical Spectral Ratio (HVSR) method has been widely used for subsurface investigation since last decade. The aimed of the research is to obtain local geological and subsurface dynamic characetristics. This research is applying the use of HVSR method for Experimental Power Reactor (RDE) in Serpong. The measurements are in 15 locations, and then the data is processed by using Geopsy software. The analysis result shows that the RDE site has dominant frequncy values between 3.06 Hz–23.271 Hz and amplification factor 1.84–6.37. The northeast and southeast areas of the site have higher seismic vulnerability index than in other area. Therefore, the selection for reactor bulding location in the southwest area is proper because it has lower amplification factor, sedimen thickness, and seismic vulnerability index.
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Sedaghati, Farhad, Sahar Rahpeyma, Anooshiravan Ansari, Shahram Pezeshk, Mehdi Zare et Siamak Daneshvaran. « A study of horizontal-to-vertical component spectral ratio as a proxy for site classification in central Asia ». Geophysical Journal International 223, no 2 (12 août 2020) : 1355–77. http://dx.doi.org/10.1093/gji/ggaa370.
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SUMMARY Tien Shan of central Asia is known as one of the world's largest, youngest and most active intracontinental orogens. In this study, we implemented the horizontal-to-vertical spectral ratio (HVSR) technique as a widely used first-order approximation of the site effect parameters (i.e. fundamental frequency and site amplification). A set of data including 2119 strong-motion recordings from 468 earthquakes with hypocentral distances up to 500 km and small to moderate moment magnitudes ($ {M_{\rm{w}}}\sim $3.0–5.5) recorded by 24 broad-band stations from five different networks, located in Afghanistan, Tajikistan and Kyrgyzstan was deployed to investigate site-specific characteristics. We fitted a Gaussian-shape pulse function to evaluate fundamental frequencies and site amplifications. The HVSRs analysis revealed that although the majority of the stations (16 out of 24) show flat amplification functions, there are few stations with single sharp amplification functions. Then, we classified the stations based on the predominant frequency. Furthermore, we approximated the time-averaged shear wave velocity in the uppermost 30 m (${V_{{\rm{S}}30}}$) using the fundamental frequency and its corresponding amplitude. Moreover, we compared the HVSRs obtained from P waves, S waves, coda and pre-event noise. All peak frequencies including the fundamental frequency estimated from different seismic phases are in good agreement; whereas generally, the amplitude of the P-wave window is the lowest, the amplitudes of the S wave and noise windows are similar to the whole record and the amplitudes of early and late coda windows are the highest. We also observed that the HVSRs of noise using a 5 s window may have anomalous high amplitudes and peaks. These anomalous high amplitudes and peaks in the noise HVSRs indicate the existence of some unnatural sources or artefacts such as traffic and wind with specific resonance frequencies, suggesting 5 s ambient noise window is insufficient to capture site characteristics. Finally, to assess the reliability of the determined geotechnical results, we implemented a blind theoretical HVSR inversion to obtain representative shear wave velocity profiles as well as ${V_{{\rm{S}}30}}$ along with associated uncertainties for stations characterized by a single-peak HVSR curve using a Bayesian statistical framework.
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Picozzi, M. « Statistical Analysis of Noise Horizontal-to-Vertical Spectral Ratios (HVSR) ». Bulletin of the Seismological Society of America 95, no 5 (1 octobre 2005) : 1779–86. http://dx.doi.org/10.1785/0120040152.
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Chandler, Val W., et Richard S. Lively. « Utility of the horizontal-to-vertical spectral ratio passive seismic method for estimating thickness of Quaternary sediments in Minnesota and adjacent parts of Wisconsin ». Interpretation 4, no 3 (1 août 2016) : SH71—SH90. http://dx.doi.org/10.1190/int-2015-0212.1.
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Quaternary glacial and fluvial sediments in Minnesota and adjacent areas are a major source for groundwater, and they are important to many geologic investigations. Unfortunately, the thicknesses of these widespread sediments are often poorly known. The horizontal-to-vertical-spectral ratio (HVSR) passive seismic method is being increasingly used in the region to assist in mapping the thickness of these sediments and the topography of the underlying bedrock surface. HVSR results when control sites with known sediment thickness are used to derive calibration curves that in turn are used to estimate sediment thicknesses in areas lacking control. The HVSR method must be used with appropriate caution. Extreme variations in S-wave velocities of near-surface materials can complicate or even negate the use of calibration curves, and very irregular bedrock surfaces can produce weak, multipeak HVSR spectra that are difficult to interpret. Over soft bedrock, HVSR peaks may reflect intrabedrock features, and velocity contrasts within the glacial sequence can overwhelm HVSR bedrock signatures. Nonetheless, the HVSR method has proven a useful tool to investigate Quaternary geology and depth to bedrock in areas of the state where subsurface data are limited. Thickness estimate errors are usually less than 25%, which is adequate for many geologic applications. The addition of multilocation spectral profiles and cross sections anchored with bedrock control points has allowed us to use data with poor signal quality and to achieve good continuity away from control stations. HVSR methods provide a suitable and cheaper alternative to conventional seismic studies, and they help to target sites for Quaternary drilling programs, bedrock topography evaluation, and determining glacial sediment thickness for 3D mapping. In areas where conventional seismic profiling may be necessary, the HVSR method is useful in selecting and prioritizing targets. The HVSR method should have widespread application in the glaciated areas of the north-central midcontinent.
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Rong, Mianshui, Xiaojun Li et Lei Fu. « Improvement of the objective function in the velocity structure inversion based on horizontal-to-vertical spectral ratio of earthquake ground motions ». Geophysical Journal International 224, no 1 (21 juillet 2020) : 1–16. http://dx.doi.org/10.1093/gji/ggaa347.
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SUMMARY Given the improvements that have been made in the forward calculations of seismic noise horizontal-to-vertical spectral ratios (NHVSRs) or earthquake ground motion HVSRs (EHVSRs), a number of HVSR inversion methods have been proposed to identify underground velocity structures. Compared with the studies on NHVSR inversion, the research on the EHVSR-based inversion methods is relatively rare. In this paper, to make full use of the widely available and constantly accumulating strong-motion observation data, we propose an S-wave HVSR inversion method based on diffuse-field approximation. Herein, the S-wave components of earthquake ground motion recordings are considered as data source. Improvements to the objective function has been achieved in this work. An objective function with the slope term is introduced. The new objective function can mitigate the multisolution phenomenon encountered when working with HVSR curves with multipeaks. Then, a synthetic case is used to show the verification of the proposed method and this method has been applied to invert underground velocity structures for six KiK-net stations based on earthquake observations. The results show that the proposed S-wave EHVSR inversion method is effective for identifying underground velocity structures.
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Praja, Nia Kurnia, Sitti Lasmi Mangininsih, Nia Kurnia Praja, Hasria et Azhar. « Pemetaan Lapisan Tanah Menggunakan Data Mikrotremor HVSR dan Dampaknya Terhadap Daya Dukung Tanah di Kawasan Kota Kendari ». Jurnal Geologi dan Sumberdaya Mineral 24, no 1 (7 février 2023) : 51–58. http://dx.doi.org/10.33332/jgsm.geologi.v24i1.724.
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Kota Kendari memiliki risiko tinggi terhadap bahaya guncangan gempa bumi karena dekat dengan sumber gempa bumi. Kondisi geologi yang heterogen menyebabkan respon berbeda terhadap efek ground motion, tergantung pada karakteristik penyusun litologi pada formasi tersebut. Untuk mengetahui karakteristik lapisan tanah, data mikrotremor HVSR (Horizontal to Vertical Spectral Ratio) digunakan dan diolah dengan software Geopsy. Horizontal to Vertical Spectral Ratioadalah satu metode yang sangat mudah untuk memperkirakan frekwensi alami dari lapisan tanah yang dikonversi dalam bentuk kecepatan gelombang geser (Vs). Nilai kecepatan gelombang geser merupakan salah satu parameter untuk mengetahui kondisi tanah serta memperkirakan bahaya ground motion secara spesifik. Kajian ini berkaitan dengan upaya mitigasi terhadap guncangan gempa bumi dengan cara memetakan daerah yang memiliki potensi kerusakan yang cukup besar terhadap gempa bumi. . Kata kunci: HVSR Mikrotremor, kecepatan gelombang geser (Vs), software Geopsy, Lapisan Tanah
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Gallipoli, Maria Rosaria, Marco Mucciarelli, Salvatore Gallicchio, Marcello Tropeano et Carmine Lizza. « Horizontal to Vertical Spectral Ratio (HVSR) Measurements in the Area Damaged by the 2002 Molise, Italy, Earthquake ». Earthquake Spectra 20, no 1_suppl (juillet 2004) : 81–93. http://dx.doi.org/10.1193/1.1766306.
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Following the 2002 Molise, Italy, earthquake, we performed a set of horizontal to vertical spectral ratio (HVSR) measurements in the damaged area. We recorded microtremors in all the municipalities reaching VI on the Mercalli-Cancani-Sieberg intensity scale. To calibrate our measurements, we installed accelerometers in two of the most damaged areas. We wanted to study HVSR in an area that is geologically different from areas commonly affected by earthquakes in the Southern Apennines. We also wanted to avoid the damage-attraction effect: after a strong event, most researchers study site amplification just where most of the damage has occurred. They might not consider that different structure vulnerability may mask the true distribution of site amplification. We checked for a possible correlation between observed intensity and the average of the non-flat HVSR measured in each municipality. The significant correlation indicates that site amplification has played a role in the damage pattern observed.
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Fattah, Elrangga Ibrahim. « Microzonation of Cisarua District Using Horizontal Vertical Spectral Ratio ». Jurnal Ilmu dan Inovasi Fisika 5, no 2 (9 août 2021) : 88–94. http://dx.doi.org/10.24198/jiif.v5i2.31533.
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The Bandung region is part of the framework of the Indonesian tectonic system, namely the tectonic plate meeting zone, where the Indo Autralia plate is infiltrated under the Eurasian plate in a convergent manner. The subduction process produces an effect in the form of an active fault geological structure in the Bandung area. One of these active faults is the Lembang Fault, which has a length of ± 29 kilometers and a shear acceleration of 3 to 5.5 millimeters per year. The microtremor measurement method is a passive geophysical method that utilizes natural subsurface vibrations so that it can provide dominant frequency data and amplification factors for soil layers. Based on the results of seismic susceptibility research using microtremor measurements using the HVSR method in the Lembang Fault zone in Cisarua Sub-District, it can be seen that the distribution of the dominant frequency values tends to be influenced by lithology and topography. In the research area, it is known to have a dominant frequency value that varies due to the different types of lithological units. In general, the dominant frequency ranges from 1-3 Hz because it is dominated by tuff sand and tuff pumice, and areas composed of volcanic breccias have a dominant frequency value between 3-6 Hz. Meanwhile, the amplification factor value will be influenced by rock deformation and weathering. The area that has a very high amplification factor value is in the southeast of the study area with an A0 value greater than 5. This indicates that the area is composed of a layer of thick and not dense tuff sand
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Qingling, Du, Liu Zhengping et Liu Shijie. « Analysis of Influencing Factors and Numerical Simulation of Horizontal-to-Vertical Spectral Ratio Method ». Journal of Earthquake and Tsunami 14, no 01 (18 septembre 2019) : 2050004. http://dx.doi.org/10.1142/s1793431120500049.
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To improve the calculation accuracy of the horizontal-to-vertical spectral ratio (HVSR) method, this study theoretically analyzed the influencing factors of Rayleigh wave polarizability. The phase difference of the horizontal component and the phase difference of the vertical component are found to play a key role in calculating the polarizability. The influence mechanism of the superposition of body waves and different Rayleigh waves on the polarizability of the Rayleigh wave is derived. The effects of the body wave, amplitude, frequency and Rayleigh wave superposition of different sources on the polarizability are verified by numerical simulation. The results show that the body wave significantly interferes with the polarizability of the Rayleigh wave. When a signal contains more than one set of Rayleigh waves, the superposition of the same-source Rayleigh waves does not affect the ratio. However, the superposition of Rayleigh waves from different sources significantly interferes with the calculation of the polarizability. This provides a technical method and a theoretical basis for accurately extracting the Rayleigh wave polarizability dispersion curve from a seismic record signal. This would help improve the detection accuracy of the HVSR method for ground pulse signals.
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Griffiths, Shawn, et Abbas Ansariaval. « Performing horizontal to vertical ratio testing in stiff soils in and around Grand Teton National Park ». UW National Parks Service Research Station Annual Reports 42 (15 décembre 2019) : 5–10. http://dx.doi.org/10.13001/uwnpsrc.2019.5733.
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Horizontal to vertical spectral ratio (HVSR) testing was completed at two cross sections in and around GTNP. The HVSR testing produced reliable estimates of the fundamental frequencies for many of the sites tested. The goal of the testing was to determine a depth of soil above competent bedrock. However the fundamental frequencies recorded yielded predicted depths that are much shallower than expected. Also the predicted depths did not increase at greater distance from the Teton Range, which would be expected at these sites. Based on these predictions the authors do not believe the frequencies recorded are a good indication of the depth of the soil above bedrock but instead it is believed that the depths correspond with a layer of softer topsoil/overburden above a stiffer gravel layer. Although the goal of measuring the depth of soil above bedrock was not met, HVSR produced results that may be useful to others for determination of a fundamental frequency of resonance at our testing locations.
Featured photo by Anna Cressman, taken from the AMK Ranch photo collection. https://flic.kr/p/2jjWZGT
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Zulfakriza, Z., N. T. Puspito, A. D. Nugraha, B. Pranata et S. Rosalia. « Preliminary Results of Horizontal to Vertical Spectral Ratio (HVSR) Across Lembang Fault, Bandung, Indonesia ». IOP Conference Series : Earth and Environmental Science 273 (16 juillet 2019) : 012020. http://dx.doi.org/10.1088/1755-1315/273/1/012020.
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Yuliawati, Winda Styani, Syamsurijal Rasimeng et Karyanto Karyanto. « PENGOLAHAN DATA MIKROTREMOR BERDASARKAN METODE HVSR DENGAN MENGGUNAKAN MATLAB ». Jurnal Geofisika Eksplorasi 5, no 1 (17 janvier 2020) : 45–59. http://dx.doi.org/10.23960/jge.v5i1.22.
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The research has conducted to get the result of Matlab program for microtremor data processing. The purpose of this research is to apply Matlab software into microtremor data processing. The microtremor is the ground motion to identify earthquake vulnerability by using HVSR (Horizontal to Vertical Spectral Ratio) method. The HVSR method for comparing both of horizontal component and vertical component on microtremor wave to obtain the result dominant frequency(f0) based on the high spectrum H/V value from the analysis of HVSR curve. Based on this research which concludes that microtremor data processing has processed using Matlab software. The result of this data processing gives similar value from the geopsy software. The value of dominant frequency by Matlab software and geopsy software calculation are classified on the site class type II which is dominantly alluvium. Whereas, the result of dominant period by geopsy and Matlab are classified on the site class type I which shows as the bedrock.
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PICOTTI, STEFANO, ROBERTO FRANCESE, MASSIMO GIORGI, FRANCO PETTENATI et JOSÉ M. CARCIONE. « Estimation of glacier thicknesses and basal properties using the horizontal-to-vertical component spectral ratio (HVSR) technique from passive seismic data ». Journal of Glaciology 63, no 238 (16 janvier 2017) : 229–48. http://dx.doi.org/10.1017/jog.2016.135.
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ABSTRACTMicrotremor measurements and the horizontal-to-vertical spectral ratio (HVSR) technique, generally used for site effect studies as well as to determine the thickness of soft sedimentary layers, can effectively be applied to map the thickness of glaciers. In this work the radio-echo sounding, geoelectric and active seismic methods, widely employed to image the earth interior, are applied to verify the reliability of the HVSR technique in Alpine and Antarctic glacial environments. The technique has been used to analyze passive seismic data from glaciers of the Adamello and Ortles-Cevedale massifs (Italy), the Bernese Oberland Alps (Switzerland) and from the Whillans Ice Stream (West Antarctica). Comparing with the results obtained from the different geophysical imaging methods, we show that the resonance frequency in the HVSR spectra correlates well with the ice thickness at the site, in a wide range from a few tens of meters to more than 800 m. The reliability of the method mainly depends on the coupling of sensors at the glacier surface and on the basal impedance contrast. This passive seismic technique offers a logistically efficient and cost effective method to map glacier and ice-sheet thicknesses. Moreover, under certain conditions, it allows reliable estimations of the basal seismic properties.
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HANSAWANGKIT, Supakorn, et Teraphan ORNTHAMMARATH. « Characteristic of Northern Thailand Seismic Stations from Horizontal-to-Vertical Spectral Ratios (HVSR) Analysis ». Walailak Journal of Science and Technology (WJST) 17, no 12 (1 décembre 2020) : 1390–98. http://dx.doi.org/10.48048/wjst.2020.10737.
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Several major cities in Northern Thailand are located on a sedimentary basin, which could amplify ground motion from future earthquakes as they lie along several active faults. To study the seismic response and natural periods of these basins, a Horizontal to Vertical Spectral Ratio (HVSR) for each seismic station in Northern Thailand has been proposed. Several observed ground motion from moderate to small seismic events in and around Northern Thailand were used in this analysis. Several seismometers (TSA-100S, Trillium-120, PA-23, S-13 and KS 2000) of the Department of Mineral Resources (DMR) and Thai Meteorological Department (TMD) with triaxial digital accelerometer data were used. The 3 axis digital accelerometers (2-horizontal and vertical) were converted to Fourier amplitude spectral (FAS) in order to find basin natural period by Horizontal to Vertical Spectral Ratio (HVSR). This research investigates 6 stations in Northern Thailand with at least 10 observed ground motions for each station. We found that the natural period of three stations (CRAI, PAYA and PHRA) showed strong site amplification effect at low natural period (between 0.1 - 0.2 s with an amplitude larger than 2). The natural period of CMMT and MHIT stations were insignificant since CMMT and MHIT were located on the rocks. Lastly, we observed long natural period for CMCA station located in Chiang Mai basin around 2.50 s with an amplitude larger than 3. Furthermore, the computed site natural periods were compared with the average top 30 m shear wave velocity (Vs30) based on the data from the Shuttle Radar Topography Mission (SRTM) and Multichannel Analysis of Surface Wave (MASW) to find the type of soil in each area.
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Perdhana, Radhitya, et Budi Eka Nurcahya. « Seismic microzonation based on microseismic data and damage distribution of 2006 Yogyakarta Earthquake ». E3S Web of Conferences 76 (2019) : 03008. http://dx.doi.org/10.1051/e3sconf/20197603008.
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The 2006 Yogyakarta earthquake caused an extensive damage to various areas of Yogyakarta regions. The damage distribution indicates the role of local site effects during the earthquake as the damage extended from Bantul Regency in Yogyakarta Province to Klaten Regency in Central Java. Microzonation based on the damage distribution is then carried out using Horizontal-to-Vertical Spectral Ratio (HVSR) technique. From this technique, amplification factor and predominant frequency can be obtained and then spatially mapped. Inversion can also be conducted to the HVSR curves to infer the geological condition of the study area.
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Sisianti, Anci, La Hamimu et Abdul Manan. « ANALISIS SPEKTRUM HVSR MIKROTREMOR UNTUK ESTIMASI KEDALAMAN BASEMENT DI DARATAN PESISIR KECAMATAN WANGI-WANGI SELATAN KABUPAEN WAKATOBI ». Jurnal Rekayasa Geofisika Indonesia 4, no 01 (30 avril 2022) : 35. http://dx.doi.org/10.56099/jrgi.v4i01.24156.
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Penelitian ini bertujuan untuk mengetahui kedalaman Basement di Kecamatan Wangi-Wangi Selatan Kabupaten Wakatobi berdasarkan sebaran spektrum HVSR data mikrotremor. Kedalaman Basement dapat diestimasi dengan menggunakan metode geofisika, salah satunya adalah dengan memanfaatkan data gelombang mikrotremor. Data mikrotremor dapat dianalisis dengan menggunakan metode Horizontal to Vertical Spectral Ratio (HVSR) yang merupakan sebagai indikator struktur bawah permukaan tanah yang memperlihatkan hubungan antara rasio spektrum Fourier dari sinyal mikrotremor komponen horisontal terhadap komponen vertikalnya. Nilai kedalaman Basement yang diperoleh dengan nilai terdangkal sebesar 6.23 m yang berada pada TP2 dan terdalam sebesar 140.80 m yang berada pada TP7. Hasil penelitian ini menunjukan bahwa berdasarkan nilai kedalaman Basement secara kualitatif daerah yang memiliki resiko tinggi mengalami kerusakan akibat gempabumi adalah kelurahan Kelurahan Liya Logo, Liya Mawi, Numana dan Kelurahan Mandati III.Kata kunci: Mikrotremor, HVSR, kedalaman Basement
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Januarta, Gabrio Hikma, Tedi Yudistira, Adrin Tohari et Erlangga Ibrahim Fattah. « MIKROZONASI SEISMIK WILAYAH PADALARANG, KABUPATEN BANDUNG BARAT MENGGUNAKAN METODE HORIZONTAL TO VERTICAL SPECTRAL RATIO (HVSR) ». RISET Geologi dan Pertambangan 30, no 2 (30 décembre 2020) : 143. http://dx.doi.org/10.14203/risetgeotam2020.v30.1087.
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Pratama, I. Putu Dedy, Dwi Karyadi Priyanto et Pande Komang Gede Arta Negara. « Ambient Noise Analysis During Nyepi in Denpasar Using Horizontal-to-Vertical Spectral Ratio (HVSR) Method ». Jurnal Geofisika 18, no 1 (29 septembre 2020) : 23. http://dx.doi.org/10.36435/jgf.v18i1.424.
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Nyepi Day is a unique tradition where outdoor human activities stop 24 hours a day. Denpasar City is the region that has the most significant impact on this change because it is the capital province. This study aims to determine the effect of Nyepi on ambient noise in Denpasar on March 25, 2020. We installed a TDS sensor at the Denpasar Geophysics Station for 3x24 hours ie when Nyepi Day, before and after Nyepi as comparative data. The data is processed by the HVSR method to get the value of dominant frequency and amplification factor every hour. Compared to the day before and after Nyepi, the dominant frequency increased during Nyepi and the amplification factor decreased during Nyepi. Seismic vulnerability index value at Nyepi is 24 where there is a decrease of index 3,904 with a day before and after Nyepi. This is showed that Nyepi Day affected ambient noise in Denpasar.
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Arimuko, A., E. Santoso et B. Sunardi. « Investigation of Site Condition Using Elliptical Curve Inversion from Horizontal-to-Vertical Spectral Ratio (HVSR) ». Journal of Physics : Conference Series 1491 (mars 2020) : 012031. http://dx.doi.org/10.1088/1742-6596/1491/1/012031.
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Dimitriu, P. P., Ch A. Papaioannou et N. P. Theodulidis. « EURO-SEISTEST strong-motion array near Thessaloniki, Northern Greece : A study of site effects ». Bulletin of the Seismological Society of America 88, no 3 (1 juin 1998) : 862–73. http://dx.doi.org/10.1785/bssa0880030862.
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Abstract The effects of local geology on the characteristics of strong ground motion have been, and continue to be, a field of active research. Despite the considerable efforts made so far, there are still several unresolved and controversial issues remaining. In particular, debates still continue over the limits of applicability of one-dimensional (1D) wave-propagation models. There are also unresolved questions related to the implementation and reliability of site-response estimation techniques such as the standard spectral ratio (SSR) and the horizontal-to-vertical spectral ratio (HVSR). This study addresses these issues on the basis of data from the EURO-SEISTEST strong-motion array at Volvi, near Thessaloniki, Greece. The data set used consists of accelerograms of 32 earthquakes, almost exclusively local, covering a magnitude range from ML 2.0 to 6.1. The range of recorded accelerations is 0.001 − 0.042 g. We implement two 1D wave-propagation models (the Haskell-Thompson matrix method and Kennett's reflectivity-coefficient method) and the HVSR site-response assessment technique. We test the applicability of the 1D models in a basin environment. We use both Fourier-amplitude and response spectra to compute HVSR and investigate how HVSR is influenced by the choice of the time window and smoothing procedure. We found the HVSR technique and 1D SH-wave modeling to perform reasonably well in a sediment-valley environment (the modeling was performed for a site in the center of the valley).
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Syaputra, Oky Dwi, Faizar Farid, Samsidar Samsidar et Linda Handayani. « IDENTIFIKASI KELAYAKAN JEMBATAN BATANGHARI II KOTA JAMBI MENGGUNAKAN MIKROTREMOR DENGAN METODE HORIZONTAL TO VERTICAL SPECTRAL RATIO (HVSR) ». Komunikasi Fisika Indonesia 16, no 1 (30 avril 2019) : 59. http://dx.doi.org/10.31258/jkfi.16.1.59-64.
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The feasibility study of Batanghari II Bridge with the value of natural frequency of Bridge using microtremor has been done. The purpose of this research is to know the bridge's natural frequency value using Horizontal to Vertical Spectral Ratio (HVSR) method and to know the relative damage to Bridge. In this study Bridge as an object because, Bridge is an alternative way that connects one place with another place separated by a river or ditch which is often used by society for activity. To get the bridge's natural frequency value using Microtremor sensor which is directly placed bridged with geopsy software to process its data and using HVSR method. The result of this research is the natural bridge frequency value of 7.40441 Hz. To determine the feasibility of the bridge compared with the standard value of the bridge frequency of 7,675 Hz and stated the state of the Batanghari II bridge is still intact from the structural and the natural frequency value of the soil on the bridge buffer of 12.7489 Hz and 13.6343 Hz that the soil type is older soil. Can be said the foundation of the bridge last long.
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Zhu, Chuanbin, Fabrice Cotton, Dong-Youp Kwak, Kun Ji, Hiroshi Kawase et Marco Pilz. « Within-site variability in earthquake site response ». Geophysical Journal International 229, no 2 (30 novembre 2021) : 1268–81. http://dx.doi.org/10.1093/gji/ggab481.
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SUMMARY The within-site variability in site response is the randomness in site response at a given site from different earthquakes and is treated as aleatory variability in current seismic hazard/risk analyses. In this study, we investigate the single-station variability in linear site response at K-NET and KiK-net stations in Japan using a large number of earthquake recordings. We found that the standard deviation of the horizontal-to-vertical Fourier spectral ratio at individual sites, that is single-station horizontal-to-vertical spectral ratio (HVSR) sigma σHV,s, approximates the within-site variability in site response quantified using surface-to-borehole spectral ratios (for oscillator frequencies higher than the site fundamental frequency) or empirical ground-motion models. Based on this finding, we then utilize the single-station HVSR sigma as a convenient tool to study the site-response variability at 697 KiK-net and 1169 K-NET sites. Our results show that at certain frequencies, stiff, rough and shallow sites, as well as small and local events tend to have a higher σHV,s. However, when being averaged over different sites, the single-station HVSR sigma, that is σHV, increases gradually with decreasing frequency. In the frequency range of 0.25–25 Hz, σHV is centred at 0.23–0.43 in ln scales (a linear scale factor of 1.26–1.54) with one standard deviation of less than 0.1. σHV is quite stable across different tectonic regions, and we present a constant, as well as earthquake magnitude- and distance-dependent σHV models.
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Lianza Bakri, Najla Insyirah, Tedi Yudistira et Yayan Sopyan. « Vulnerability Analysis of Earthquake Hazards in Tasikmalaya City Using Horizontal to Vertical Spectral Ratio (HVSR) Method ». IOP Conference Series : Earth and Environmental Science 873, no 1 (1 octobre 2021) : 012085. http://dx.doi.org/10.1088/1755-1315/873/1/012085.
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Abstract Tasikmalaya City is one of the regions in West Java Province that is often hit by earthquakes due to its location near the Indo-Australian Plate subduction zone towards the Eurasian Plate. The surface deposits in this city are alluvium and weakly consolidated step deposits which can cause wave amplification during an earthquake. As a mitigation effort, seismic zoning needs to be carried out to map the areas that will experience heavy damage when an earthquake occurs. This study uses the Horizontal to Vertical Spectral Ratio (HVSR) method which is applied to the microtremor recording data to obtain spatial variations in the predominant frequency and amplification values that can explain the characteristics of the geological layer beneath the surface. Based on the obtained results, the predominant frequency ranging from 0.7 to 9.5 Hz with the lowest frequency distribution in the eastern and northwestern parts, which indicates a thicker sediment layer. Amplification ranging from 1.2 to 12.6 with the distribution of higher values in the eastern, southeastern, and northwestern parts. The inversion of the HVSR curves was carried out to determine the value of shear wave velocity (V s ) in order to obtain a more detailed subsurface geological structure that can be used to determine the level of vulnerability of earthquake hazards. The Neighborhood Algorithm is used to find an optimum model. Based on the results of the inversion process, the V s ranging from 150 - 3054 m/s with lower V s values in the eastern, southeastern, and northwestern parts at depth of about 25 meters. The average value of shear wave velocity at a depth of 30 meters (V s 30) can also be used to determine the type of soil for geotechnical study. From the obtained V s 30data, the types of soil in the research area are classified into moderate soil, hard soil, and rocks.
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Cheng, Tianjian, Brady R. Cox, Joseph P. Vantassel et Lance Manuel. « A statistical approach to account for azimuthal variability in single-station HVSR measurements ». Geophysical Journal International 223, no 2 (17 juillet 2020) : 1040–53. http://dx.doi.org/10.1093/gji/ggaa342.
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SUMMARY The horizontal-to-vertical spectral ratio (HVSR) of ambient noise is commonly used to infer a site's resonance frequency (${f_{0,site}}$). HVSR calculations are performed most commonly using the Fourier amplitude spectrum obtained from a single merged horizontal component (e.g. the geometric mean component) from a three-component sensor. However, the use of a single merged horizontal component implicitly relies on the assumptions of azimuthally isotropic seismic noise and 1-D surface and subsurface conditions. These assumptions may not be justified at many sites, leading to azimuthal variability in HVSR measurements that cannot be accounted for using a single merged component. This paper proposes a new statistical method to account for azimuthal variability in the peak frequency of HVSR curves (${f_{0,HVSR}}$). The method uses rotated horizontal components at evenly distributed azimuthal intervals to investigate and quantify azimuthal variability. To ensure unbiased statistics for ${f_{0,HVSR}}$ are obtained, a frequency-domain window-rejection algorithm is applied at each azimuth to automatically remove contaminated time windows in which the ${f_{0,HVSR}}$ values are statistical outliers relative to those obtained from the majority of windows at that azimuth. Then, a weighting scheme is used to account for different numbers of accepted time windows at each azimuth. The new method is applied to a data set of 114 HVSR measurements with significant azimuthal variability in ${f_{0,HVSR}}$, and is shown to reliably account for this variability. The methodology is also extended to the estimation of a complete lognormal-median HVSR curve that accounts for azimuthal variability. To encourage the adoption of this statistical approach to accounting for azimuthal variability in single-station HVSR measurements, the methods presented in this paper have been incorporated into hvsrpy, an open-source Python package for HVSR processing.
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Wood, Clinton M., et Brady R. Cox. « Comparison of Field Data Processing Methods for the Evaluation of Topographic Effects ». Earthquake Spectra 32, no 4 (novembre 2016) : 2127–47. http://dx.doi.org/10.1193/111515eqs170m.
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This paper presents a comparison of field data processing methods used to evaluate topographic effects. A data set of 52 weak motion events recorded using a dense array of seismometers located on steep, complex topography is analyzed. Both time domain and frequency domain analysis methods are evaluated for effectiveness at resolving the amplitude and frequency range associated with topographic effects. Results from this study indicate the median reference method (MRM) provides a more stable estimate of the frequency range and expected amplification value than the standard spectral ratio (SSR) or horizontal-to-vertical spectral ratio (HVSR) methods.
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KUSUMAWARDANI, RINI, Untoro Nugroho, Sri Handayani et Mareta Aspirilia Fananda. « THE ANALYSIS OF LIQUEFACTION PHENOMENON OF THE FLEXIBLE PAVEMENT USING SEISMIC MONITORING EQUIPMENT ». IIUM Engineering Journal 20, no 1 (1 juin 2019) : 70–78. http://dx.doi.org/10.31436/iiumej.v20i1.1031.
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ABSTRACT: Liquefaction phenomenon is generally caused by high dynamic vibrations in a very fast duration. This article investigated the behavior of dynamic vibrations caused by vehicles on the road. This study employed the HVSR (Horizontal Vertical Spectral Ratio) with an accelerometer. The result of dynamic vibration generated by the passing vehicle or the micro tremor / micro seismic vibration was recorded by seismic monitoring devices. This seismic monitoring equipment converted vibration into natural frequency (f0) and amplification (A0) using Geopsy software. The result of HVSR (Horizontal Vertical Spectral Ratio) was the soil vulnerability index (Kg). The results of this study indicated that the three parameters above were then analyzed with the assumption that if the amplification value (A0) was higher and associated with a lower natural frequency value (Æ’0) with a high vulnerability index (Kg), then the area had the potential liquefaction, with laboratory research results in the form of granular gradation testing as the supporting data. Therefore, the results of the analysis and the laboratory can concluded that the three research locations have the potential liquefaction.
ABSTRAK: Fenomena pececairan umumnya disebabkan oleh adanya getaran dinamik tinggi dalam tempoh yang sangat cepat. Artikel ini mengkaji fenomena getaran dinamik yang disebabkan oleh kenderaan di jalan raya. Kajian ini menggunakan HVSR (Nisbah Spektral Menegak Mendatar) dengan pecutan. Hasil getaran dinamik yang dihasilkan oleh kenderaan yang melalui atau gegaran mikro / mikro getaran seismik dicatatkan oleh alat pemantauan seismik. Peralatan pemantauan seismik ini mengubah getaran ke frekuensi semula jadi (f0) dan amplifikasi (A0) menggunakan perisian Geopsy. Hasil HVSR (Nisbah Spektral Vertikal Mendatar) adalah indeks kelemahan tanah (Kg). Keputusan kajian ini menunjukkan bahawa ketiga-tiga parameter di atas kemudian dianalisis dengan anggapan bahawa jika nilai amplifikasi (A0) lebih tinggi dan dikaitkan dengan nilai kekerapan semulajadi yang lebih rendah (Æ’0) dengan indeks kelemahan tinggi (Kg), maka kawasan mempunyai potensi pencairan, dengan hasil penyelidikan makmal berupa pengujian gradasi granular sebagai data pendukung. Oleh itu, hasil analisis dan makmal dapat menyimpulkan bahawa tiga lokasi penyelidikan mempunyai potensi adanya pececairan.
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Neroni, Regis, Kevin Stephens et Daniel Dwumfour. « Application of the passive seismic Horizontal-to-Vertical Spectral Ratio (HVSR) technique for embankment integrity monitoring ». ASEG Extended Abstracts 2018, no 1 (décembre 2018) : 1–6. http://dx.doi.org/10.1071/aseg2018abm1_4h.
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Dal Moro, Giancarlo. « On the Identification of Industrial Components in the Horizontal-to-Vertical Spectral Ratio (HVSR) from Microtremors ». Pure and Applied Geophysics 177, no 8 (5 février 2020) : 3831–49. http://dx.doi.org/10.1007/s00024-020-02424-0.
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Zhu, Chuanbin, Fabrice Cotton et Marco Pilz. « Detecting Site Resonant Frequency Using HVSR : Fourier versus Response Spectrum and the First versus the Highest Peak Frequency ». Bulletin of the Seismological Society of America 110, no 2 (3 mars 2020) : 427–40. http://dx.doi.org/10.1785/0120190186.
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ABSTRACT In this investigation, we examine the uncertainties using the horizontal-to-vertical spectral ratio (HVSR) technique on earthquake recordings to detect site resonant frequencies at 207 KiK-net sites. Our results show that the scenario dependence of response (pseudospectral acceleration) spectral ratio could bias the estimates of resonant frequencies for sites having multiple significant peaks with comparable amplitudes. Thus, the Fourier amplitude spectrum (FAS) should be preferred in computing HVSR. For more than 80% of the investigated sites, the first peak (in the frequency domain) on the average HVSR curve over multiple sites coincides with the highest peak. However, for sites with multiple peaks, the highest peak frequency (fp) is less susceptible to the selection criteria of significant peaks and the extent of smoothing to spectrum than the first peak frequency (f0). Meanwhile, in comparison to the surface-to-borehole spectral ratio, f0 tends to underestimate the predominant frequency (at which the largest amplification occurs) more than fp. In addition, in terms of characterizing linear site response, fp shows a better overall performance than f0. Based on these findings, we thus recommend that seismic network operators provide fp on the average HVSRFAS curve as a priority, ideally together with the average HVSRFAS curve in site characterization.
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Tchawe, F. N., B. Froment, M. Campillo et L. Margerin. « On the use of the coda of seismic noise autocorrelations to compute H/V spectral ratios ». Geophysical Journal International 220, no 3 (6 décembre 2019) : 1956–64. http://dx.doi.org/10.1093/gji/ggz553.
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SUMMARY The horizontal to vertical spectral ratio (HVSR) of seismic ambient noise has been proven to be a fast and efficient method for characterizing the 1-D resonance frequency of the local subsurface in a practical framework. Over the last decades, theories have been developed in order to extend the exploitation of HVSR beside the frequency of its first peak, notably the diffuse field assumption (DFA) which links the HVSR to the Green’s function of the local medium assuming the diffuseness of the seismic ambient noise wavefield. However, the underlying assumption of the seismic ambient noise being a diffuse, equipartitioned field may not be satisfied under certain circumstances. In order to exploit the contribution of scattering in forging diffuse wave fields, we leverage the advantages of coda waves and present a novel procedure for computing the HVSR, using the coda part of ambient noise correlations. We applied this technique to data gathered at the plio-quaternary sedimentary basin of Argostoli, Greece. Results on this data set show the potential of the method to improve the temporal stability of the HVSR measurements compared to the classical computation, and the fit with the theoretical HVSR curve derived from the DFA theory. These results suggest that this procedure could help in extracting physical information from the HVSR and thus could lead to an extended use of these measurements to characterize the mechanical properties of the medium.
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Prabowo, Urip Nurwijayanto, Akmal Ferdiyan et Ayu Fitri Amalia. « The Soft Layer Thickness Estimation using Microtremor Measurement to Identify Landside Potential in Watukumpul, Central Java, Indonesia. » Journal of Geoscience, Engineering, Environment, and Technology 6, no 1 (24 mars 2021) : 16–23. http://dx.doi.org/10.25299/jgeet.2021.6.1.5436.
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Watukumpul is an area that is prone to landslides, so determining the soft layer thickness is very important to identify the landslide potential. The soft layer thickness can be estimated using microtremor signal measurements which analyzed using the Horizontal to Vertical Spectral Ratio (HVSR). In this study,we measured microtremor signal of 33location around Watukumpul, Pemalang, Central Java area to determine soft layer thickness. Micretremor signal was analyzed based on theHVSR method using Geopsy software and follow the standard of the Sesame Europan Project. The results of the HVSR method are the HVSR curve that fulfills the reliable curve standard. HVSR curve shows that the dominant frequency of soft layer ranges from 1.36 – 7.62 Hz and the amplification values ranges from 9.00 – 41.45. The soft layer thickness value in the study area ranges from 17.58 - 103.60 meters. The high landslide potential area are located at W7, W8, W18, W30 and W32 where has thin soft layer and high soil slope.
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Capizzi, Patrizia, et Raffaele Martorana. « Analysis of HVSR Data Using a Modified Centroid-Based Algorithm for Near-Surface Geological Reconstruction ». Geosciences 12, no 4 (24 mars 2022) : 147. http://dx.doi.org/10.3390/geosciences12040147.
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Recently, the use of microtremor techniques for subsoil investigation has increased significantly. The HVSR (Horizontal to Vertical Spectral Ratio) technique allows, in many cases, to obtain a seismo-stratigraphic reconstruction of the subsoil and to identify areas with similar seismic behavior. However, the stratigraphic interpretation of the HVSR peaks still remains a subjective choice and linked to a priori information. A non-hierarchical centroid-based algorithm was modified to group HVSR peaks of different measurements that can be attributed to the same generating seismic discontinuity. Some tests performed have shown that the proposed algorithm produces valid results even in the absence of a priori information to evaluate the choice of the optimal grouping. The results obtained for HVSR measurements acquired in the city of Modica (Italy) are presented. The cluster analysis of these data and the information on the lithologies outcropping in the area made it possible to reconstruct a 3D model of the main seismo-stratigraphic discontinuities.
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La Rocca, M., G. D. Chiappetta, A. Gervasi et R. L. Festa. « Non-stability of the noise HVSR at sites near or on topographic heights ». Geophysical Journal International 222, no 3 (17 juin 2020) : 2162–71. http://dx.doi.org/10.1093/gji/ggaa297.
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SUMMARY The horizontal to vertical spectral ratio (HVSR) of seismic noise is often used to investigate site effects, and it is usually assumed to be a stable feature of the site considered. Here we show that such an assumption is not always justified, and may lead to incorrect conclusions. The HVSR analysis was performed on ambient seismic noise recordings lasting from weeks to months at many sites in Calabria, Italy. Results show a variety of site effects, from the resonance of a shallow sedimentary layer to the polarized amplification of horizontal ground motion associated with topographic effects. We describe the results of seven sites whose HVSR is characterized by dual content: one that is persistent, and another appearing only occasionally. Two sites very near the coast of the Tyrrhenian sea and five sites in the Calabrian Arc mountains show the most remarkable results. The shape of the HVSR changes significantly at these sites when the amplitude of background noise increases in a broad frequency band during periods of bad weather. The occasional contribution to the HVSR consists of one or more peaks, depending on the site, that appear only when the amplitude of ambient noise is higher than usual. The seven sites where we observe the HVSR variability are all located in complex geological environments, on mountains, ridges or foothills. A variation of the HVSR correlated with the day–night cycle is also observed at some of these sites.
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Amrullah, Muhammad Khemal, Maulana Rizki Aditama, Fx Anjar Tri Laksono et Asmoro Widagdo. « Analisis Ground Motion di Selatan Gunung Api Ungaran Berdasarkan Mikrozonasi Metode Horizontal to Vertical Spectral Ratio (HVSR) ». Jurnal Geosains dan Teknologi 4, no 3 (31 août 2021) : 134–41. http://dx.doi.org/10.14710/jgt.4.3.2021.134-141.
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Salah satu mitigasi bencana yang dapat dilakukan untuk mengidentifikasi daerah yang berpotensi mengalami pergerakan tanah adalah analisis mikrotremor dengan metode Horizontal to Vertical Spectral Ratio (HVSR) yang menghasilkan parameter frekuensi dominan dan amplifikasi. Kedua data tersebut digunakan untuk mencari nilai indeks kerentanan seismik, ketebalan lapisan sedimen, dan peak ground acceleration yang dijadikan sebagai parameter untuk dianalisis dalam mengidentifikasi daerah yang berpotensi mengalami pergerakan tanah. Pada daerah penelitian nilai indeks kerentanan seismik terendah 0,15 s2/cm dan tertinggi 33,74 s2/cm, ketebalan sedimen paling tipis pada Vs 175 m/s adalah 3,24 m dan ketebalan lapisan sedimen paling tebal adalah 33,71 m, sedangkan pada Vs 350 m/s ketebalan paling tipis adalah 6,48 m dan ketebalan sedimen paling tebal adalah 67,43 m, serta nilai peak ground acceleration paling tinggi adalah 48,48 gal dan paling rendah adalah adalah 14,91 gal. Berdasarkan analisis data microtremor, nilai indeks kerentanan seismik, lapisan sedimen, depth of boundary, dan peak ground acceleration, daerah yang memiliki potensi pergerakan tanah yang relatif tinggi berada di titik MS12, MS14, MS15, MS20, MS21, dan MS23.
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Sarmadi, Mohammad Ali, Reza Heidari, Noorbakhsh Mirzaei et Hamid Reza Siahkoohi. « The improvement of the earthquake and microseismic Horizontal-to-Vertical Spectral Ratio (HVSR) in estimating site effects ». Acta Geophysica 69, no 4 (12 juin 2021) : 1177–88. http://dx.doi.org/10.1007/s11600-021-00619-0.
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Widia Pamungkas Isburhan, Rosliani, Giyat Nuraeni, Rexha Verdhora Ry, Tedi Yudistira, Anthanius Cipta et Phil Cummins. « Horizontal-to-Vertical Spectral Ratio (HVSR) Method for Earthquake Risk Determination of Jakarta City with Microtremor Data ». IOP Conference Series : Earth and Environmental Science 318 (14 août 2019) : 012033. http://dx.doi.org/10.1088/1755-1315/318/1/012033.
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Prabowo, Urip Nurwijayanto, Sehah Sehah et Akmal Ferdiyan. « Estimasi ketebalan lapisan sedimen permukaan menggunakan pengukuran mikrotremor di Pemalang, Jawa Tengah ». Jurnal Teras Fisika 4, no 1 (1 juillet 2021) : 187. http://dx.doi.org/10.20884/1.jtf.2021.4.1.3436.
Texte intégralRésumé :
Ketebalan lapisan sedimen permukaan merupakan salah satu parameter yang menggambarkan kondisi geologi pemukaan suatu daerah saat mengalami gempabumi. Ketebalan lapisan sedimen dapat diperkirakan menggunakan pengukuran mikrotremor yang dianalisis menggunakan metode Horizontal to vertical Spectral Ratio (HVSR). Pada penelitian ini dilakukan pengukuran mikrotremor sebanyak 5 titik di daerah Pemalang, Jawa Tengah yang secara geologi tersusun atas aluvium berumur kuarter. Hasil pengolahan data pengukuran mikrotremor menggunakan metode HVSR adalah frekuensi dominan daerah penelitian yang berkisar antara 1,56 – 11,56 Hz dan ketebalan lapisan sedimen permukaan berkisar antara 4,49 – 33,70 m. Ketebalan lapisan sedimen permukaan memiliki nilai yang semakin besar ke arah pantai (selatan). Hasil analisis menunjukkan bahwa morfologi bedrock cenderung mengikuti pola dari ketebalan lapisan sedimen karena perbedaan elevasi permukaan yang relatif kecil pada titik pengukuran.
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Köhler, Andreas, et Christian Weidle. « Potentials and pitfalls of permafrost active layer monitoring using the HVSR method : a case study in Svalbard ». Earth Surface Dynamics 7, no 1 (10 janvier 2019) : 1–16. http://dx.doi.org/10.5194/esurf-7-1-2019.
Texte intégralRésumé :
Abstract. Time-lapse monitoring of the subsurface using ambient seismic noise is a popular method in environmental seismology. We assess the reliability of the horizontal-to-vertical spectral ratio (HVSR) method for monitoring seasonal permafrost active layer variability in northwest Svalbard. We observe complex HVSR variability between 1 and 50 Hz in the record of a temporary seismic deployment covering frozen and thawed soil conditions between April and August 2016. While strong variations are due to changing noise conditions, mainly affected by wind speed and degrading coupling of instruments during melt season, a seasonal trend is observed at some stations that has most likely a subsurface structural cause. A HVSR peak emerges close to the Nyquist frequency (50 Hz) in beginning of June which is then gradually gliding down, reaching frequencies of about 15–25 Hz in the end of August. This observation is consistent with HVSR forward modeling for a set of structural models that simulate different stages of active layer thawing. Our results reveal a number of potential pitfalls when interpreting HVSRs and suggest a careful analysis of temporal variations since HVSR seasonality is not necessarily related to changes in the subsurface. In addition, we investigate if effects of changing noise sources on HVSRs can be avoided by utilizing a directional, narrowband (4.5 Hz) repeating seismic tremor which is observed at the permanent seismic broadband station in the study area. A significant change of the radial component HVSR shape during summer months is observed for all tremors. We show that a thawed active layer with very low seismic velocities would affect Rayleigh wave ellipticities in the tremor frequency band. We compile a list of recommendations for future experiments, including comments on network layouts suitable for array beamforming and waveform correlation methods that can provide essential information on noise source variability.
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Schleicher, Lisa S., et Thomas L. Pratt. « Characterizing Fundamental Resonance Peaks on Flat-Lying Sediments Using Multiple Spectral Ratio Methods : An Example from the Atlantic Coastal Plain, Eastern United States ». Bulletin of the Seismological Society of America 111, no 4 (6 juillet 2021) : 1824–48. http://dx.doi.org/10.1785/0120210017.
Texte intégralRésumé :
ABSTRACT Damaging ground motions from the 2011 Mw 5.8 Virginia earthquake were likely increased due to site amplification from the unconsolidated sediments of the Atlantic Coastal Plain (ACP), highlighting the need to understand site response on these widespread strata along the coastal regions of the eastern United States. The horizontal-to-vertical spectral ratio (HVSR) method, using either earthquake signals or ambient noise as input, offers an appealing method for measuring site response on laterally extensive sediments, because it requires a single seismometer rather than requiring a nearby bedrock site to compute a horizontal sediment-to-bedrock spectral ratio (SBSR). Although previous studies show mixed results when comparing the two methods, the majority of these studies investigated site responses in confined sedimentary basins that can generate substantial 3D effects or have relatively small reflection coefficients at their base. In contrast, the flat-lying ACP strata and the underlying bedrock reflector should cause 1D resonance effects to dominate site response, with amplification of the fundamental resonance peaks controlled by the strong impedance contrast between the base of the sediments and the underlying bedrock. We compare site-response estimates on the ACP strata derived using the HVSR and SBSR methods from teleseismic signals recorded by regional arrays and observe a close match in the frequencies of the fundamental resonance peak (f0) determined by both methods. We find that correcting the HVSR amplitude using source term information from a bedrock site and multiplying the peak by a factor of 1.2 results in amplitude peaks that, on average, match SBSR results within a factor of 2. We therefore conclude that the HVSR method may successfully estimate regional linear weak-motion site-response amplifications from the ACP, or similar geologic environments, when appropriate region-specific corrections to the amplitude ratios are used.
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Badrolhisham, Siti Noor Shafiqah, et Abdul Halim Abdul Latiff. « Integrated Seismic Hazard Analysis Of Southwest Penang Island Through Horizontal-To-Vertical Spectral Ratio And Probabilistic Seismic Hazard Assessment ». Bulletin of the Geological Society of Malaysia 71 (31 mai 2021) : 79–87. http://dx.doi.org/10.7186/bgsm71202107.
Texte intégralRésumé :
Peninsular Malaysia is susceptible to large magnitude earthquakes induced by the regional sources as it is surrounded by countries that are known for their active seismicity. Tremors were felt in Penang Island of Pulau Pinang due to earthquake events in Sumatra, Indonesia in 2005 and 2009. Presence of cracks on buildings in the island was reported caused by the earthquake on 2nd November 2002. The tsunami that hit the island on 26 December 2004 was the aftermath of the Great Sumatra-Andaman earthquake with magnitude 9.1. The investigation of earthquake risks ensures that the effect of earthquake disasters in the inclined region can be reduced effectively. This paper aims to provide a comprehensive seismic hazard assessment in Penang Island by analysing the predominant natural frequency distribution in Balik Pulau through a passive seismic survey method known as horizontal-to-vertical spectral ratio (HVSR) and evaluating the ground motion throughout the island using probabilistic seismic hazard assessment (PSHA) approach. The natural frequencies of Balik Pulau mostly falls in the range of 3 to 4 Hz which is associated with loose deposits and stiff soil layer. The amplification factor extracted from the HVSR curves ranges approximately 4 to 5. The minimum ground motions estimated for a fixed intensity in 50 years for Penang Island is 0.006 g1 and can reach up to 0.025 g. While the minimum ground motions for a fixed return period of 98 years in 50 years is 0.016 g with maximum of 0.035 g.
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Norda, M. E., A. Prapiga, P. Paraskevopoulos et G. A. Tselentis. « A STUDY OF MICROTREMOR HVSR IN THE RIO-ANTIRIO AREA, (GREECE) ». Bulletin of the Geological Society of Greece 50, no 3 (27 juillet 2017) : 1194. http://dx.doi.org/10.12681/bgsg.11825.
Texte intégralRésumé :
Horizontal to Vertical Spectral Ratio (HVSR) method has been applied on ambient noise records at the Rio- Antirio area (central Greece). The dataset used was recorded during 7 days by 12 temporary seismic stations deployed in the area. The stations were laid out along a profile and their interval was approximately 500m. The main part of the processing was done using Geopsy software. The aim of this study was to estimate the fundamental frequency at the station sites and its variation with time and azimuth. The processing results showed that for most stations along the profile, the peaks of the HVSR curve are not strong enough and often there are, more than one, peaks, which seem to be persistent during the whole recording time. When taking the azimuth into account, some of the stations show dominant and persistent directions were the HVSR ratio is stronger, while it has been observed that this direction could vary for different frequency peaks of the same stations. Finally, the top sediment layer’s geometry and thickness were estimated using Vs velocity results from nearby crosshole measurements.
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Neukirch, Maik, Antonio García-Jerez, Antonio Villaseñor, Francisco Luzón, Jacques Brives et Laurent Stehly. « On the Utility of Horizontal-to-Vertical Spectral Ratios of Ambient Noise in Joint Inversion with Rayleigh Wave Dispersion Curves for the Large-N Maupasacq Experiment ». Sensors 21, no 17 (4 septembre 2021) : 5946. http://dx.doi.org/10.3390/s21175946.
Texte intégralRésumé :
Horizontal-to-Vertical Spectral Ratios (HVSR) and Rayleigh group velocity dispersion curves (DC) can be used to estimate the shallow S-wave velocity (VS) structure. Knowing the VS structure is important for geophysical data interpretation either in order to better constrain data inversions for P-wave velocity (VP) structures such as travel time tomography or full waveform inversions or to directly study the VS structure for geo-engineering purposes (e.g., ground motion prediction). The joint inversion of HVSR and dispersion data for 1D VS structure allows characterising the uppermost crust and near surface, where the HVSR data (0.03 to 10s) are most sensitive while the dispersion data (1 to 30s) constrain the deeper model which would, otherwise, add complexity to the HVSR data inversion and adversely affect its convergence. During a large-scale experiment, 197 three-component short-period stations, 41 broad band instruments and 190 geophones were continuously operated for 6 months (April to October 2017) covering an area of approximately 1500km2 with a site spacing of approximately 1 to 3km. Joint inversion of HVSR and DC allowed estimating VS and, to some extent density, down to depths of around 1000m. Broadband and short period instruments performed statistically better than geophone nodes due to the latter’s gap in sensitivity between HVSR and DC. It may be possible to use HVSR data in a joint inversion with DC, increasing resolution for the shallower layers and/or alleviating the absence of short period DC data, which may be harder to obtain. By including HVSR to DC inversions, confidence improvements of two to three times for layers above 300m were achieved. Furthermore, HVSR/DC joint inversion may be useful to generate initial models for 3D tomographic inversions in large scale deployments. Lastly, the joint inversion of HVSR and DC data can be sensitive to density but this sensitivity is situational and depends strongly on the other inversion parameters, namely VS and VP. Density estimates from a HVSR/DC joint inversion should be treated with care, while some subsurface structures may be sensitive, others are clearly not. Inclusion of gravity inversion to HVSR/DC joint inversion may be possible and prove useful.
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Mendecki, Maciej Jan, Barbara Bieta et Mateusz Mycka. « Determination of the resonance frequency – thickness relation based on the ambient seismic noise records from Upper Silesia Coal Basin ». Contemporary Trends in Geoscience 3, no 1 (1 septembre 2014) : 41–51. http://dx.doi.org/10.2478/ctg-2014-0021.
Texte intégralRésumé :
Abstract In this paper the Horizontal-to-Vertical Spectral Ratio (HVSR) method and seismic data were applied to evaluate the resonance frequency - thickness relation. The HVSR method was used to estimate the parameters of site effects: amplification and resonance frequency from seismic noise records. The seismic noise was generated by artificial source occurring in Upper Silesia Coal Basin (UBSC), Poland, such as: traffic, industry, coal plants etc. The survey points were located near the Faculty of Earth Sciences in Sosnowiec, Bytom and Chorzow. Based on Albarello’s statistical test the observed H/V maxima was confirmed or rejected. Resonance frequencies were compared with available thicknesses of soft layer obtained by seismic survey (Mendecki 2012). Finally, the estimated resonance frequency - thickness relation for UBSC area showed quite similar power function coefficients as those obtained by other authors
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Badrolhisham, Siti Noor Shafiqah, Amin Esmail Khalil, Wong Kian Wai et Abdul Halim Abdul Latiff. « Evaluation of site effects using horizontal-to-vertical spectral ratio in Kuala Pilah, Negeri Sembilan ». IOP Conference Series : Earth and Environmental Science 1003, no 1 (1 avril 2022) : 012036. http://dx.doi.org/10.1088/1755-1315/1003/1/012036.
Texte intégralRésumé :
Abstract The destruction experienced by an area due to tremors is commonly related to the size of magnitude and the distance of the source to the site where it is well known that larger magnitude earthquakes cause greater damage. Similarly, the closest area to the source will experience much devastating damage compared to the area further away. In addition to that, the local site effect also plays a significant role in the impact of earthquake hazards for specific sites despite the site being hundreds of kilometers away from the epicenter. This had been proven by the Michoacán earthquake in 1985 where the situation is similar to Peninsular Malaysia located approximately 400 km away from one of the most active plate tectonics in the world, the Sumatra Subduction Zone. This paper aims to evaluate the local site effects to improve the result of seismic hazard assessment by applying the Horizontal-to-Vertical Spectral Ratio (HVSR) method. The recorded microtremors data are processed to get two parameters that are closely related to the local site condition which is the resonant frequency and the amplification factor. The overall values extracted from the H/V curves are intermediate for both parameters. Overall, Kuala Pilah is divided into two zones; the western region associated with a thin, well-compacted soil layer and the eastern region associated with loose and unconsolidated deposits.