scholarly journals PENGOLAHAN DATA MIKROTREMOR BERDASARKAN METODE HVSR DENGAN MENGGUNAKAN MATLAB

2020 ◽  
Vol 5 (1) ◽  
pp. 45-59
Author(s):  
Winda Styani Yuliawati ◽  
Syamsurijal Rasimeng ◽  
Karyanto Karyanto
Keyword(s):  
Data Processing ◽  
Vertical Component ◽  
Spectral Ratio ◽  
Dominant Frequency ◽  
Ratio Method ◽  
Type I ◽  
Site Class ◽  
Matlab Software ◽  
Hvsr Method ◽  
Earthquake Vulnerability

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.

scholarly journals The Soft Layer Thickness Estimation using Microtremor Measurement to Identify Landside Potential in Watukumpul, Central Java, Indonesia.

2021 ◽  
Vol 6 (1) ◽  
pp. 16-23
Author(s):  
Urip Nurwijayanto Prabowo ◽  
Akmal Ferdiyan ◽  
Ayu Fitri Amalia
Keyword(s):  
Layer Thickness ◽  
Spectral Ratio ◽  
Dominant Frequency ◽  
Soil Slope ◽  
Soft Layer ◽  
Thickness Estimation ◽  
Central Java ◽  
Hvsr Method ◽  
Microtremor Measurement ◽  
Potential Area

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.

scholarly journals ANALISIS TINGKAT RESIKO DAMPAK GEMPABUMI DI KABUPATEN CILACAP MENGGUNAKAN METODE DSHA DAN DATA MIKROTREMOR

2020 ◽  
Vol 4 (3) ◽  
pp. 73-89
Author(s):  
Kukuh Dialosa ◽  
Rustadi Rustadi ◽  
Bagus Sapto Mulyatno ◽  
Cecep Sulaeman
Keyword(s):  
Hazard Analysis ◽  
Soil Layer ◽  
Spectral Ratio ◽  
Dominant Frequency ◽  
Soil Class ◽  
Land Type ◽  
Short Period ◽  
Hvsr Method ◽  
Ability Factor ◽  
Microtremor Measurement

Soil mechanical research has been done in Cilacap Regency using DSHA method and microtremor data. This study aims to analyze the local land response to earthquakes based on the dominant frequency parameters (f0), amplification factor (A0), wave velocity VS30 and seismic hazard analysis through deterministic approach. This research uses 193 microtremor measurement points using a short period TDS-303 type (3 component) seismometer. Microtremor data were analyzed using the Horizontal to Vertical Spectral Ratio (HVSR) method in geopsy software. DSHA analysis refers to the source of the Lembang Fault earthquake and Java Subduction zone for deterministic calculations. Based on the analysis of HVSR method, Cilacap Regency is located on land type 1 (frequency 0-1.33 Hz) and soil type 2 (frequency 1,33-5 Hz) according to Kanai Classification (1983), dominated amplification value 1,104 to 8,171 times, then Dominated by soil class E (VS30 value 183 m / s) and soil class D (183 m / s VS30 366 m / s) according to NEHRP Classification (2000). This indicates that Cilacap Regency has high vulnerability to earthquake disaster. Based on the estimated value of PGA calculation method of DSHA, from the calculation of earthquake source Subduction obtained Java PGA bedrock 0,045 g - 0,0671 g and PGA surface rock 0,1926 g - 0,4855 g and calculation of Lembang Fault obtained PGA bedrock 0, 09 g - 0.025 g and PGA surface rocks 0.017 g - 0.089 g. Based on risk map analysis (combination of dominant frequency analysis, amplification, susceptibility factor and ability factor), the highest risk areas are Kec. Adipala, Kasugihan, Binangun, Nusawungun, Cil. Middle, Cil. South, Cil. North, allegedly the soil layer constituent area is a layer of thick and soft sediments. While the low risk of Kec. Majenang and Dayeuh Luhur.

scholarly journals Microzonation of Cisarua District Using Horizontal Vertical Spectral Ratio

2021 ◽  
Vol 5 (2) ◽  
pp. 88-94
Author(s):  
Elrangga Ibrahim Fattah ◽  
Keyword(s):  
Amplification Factor ◽  
Active Faults ◽  
Spectral Ratio ◽  
Dominant Frequency ◽  
Research Area ◽  
Geological Structure ◽  
Eurasian Plate ◽  
Hvsr Method ◽  
Microtremor Measurement ◽  
Tectonic System

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

scholarly journals Ambient Noise Analysis During Nyepi in Denpasar Using Horizontal-to-Vertical Spectral Ratio (HVSR) Method

2020 ◽  
Vol 18 (1) ◽  
pp. 23
Author(s):  
I Putu Dedy Pratama ◽  
Dwi Karyadi Priyanto ◽  
Pande Komang Gede Arta Negara
Keyword(s):  
Ambient Noise ◽  
Seismic Vulnerability ◽  
Amplification Factor ◽  
Noise Analysis ◽  
Spectral Ratio ◽  
Vulnerability Index ◽  
Dominant Frequency ◽  
Before And After ◽  
Hvsr Method ◽  
Index Value

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.

scholarly journals INVERSI MIKROTREMOR UNTUK PROFILING KECEPATAN GELOMBANG GESER (Vs) DAN MIKOROZONASI KABUPATEN BANDUNG

2020 ◽  
Vol 5 (2) ◽  
pp. 3-14
Author(s):  
Andina Zuhaera ◽  
Suharno Suharno ◽  
Bagus Sapto Mulyatno
Keyword(s):  
Soft Rock ◽  
Spectral Ratio ◽  
Dominant Frequency ◽  
Soil Characteristics ◽  
Northern Region ◽  
Wave Amplification ◽  
A Value ◽  
Hvsr Method ◽  
The Difference ◽  
The Impact

Bandung Regency is a highland area with a slope between 0 - 8%, 8-15% to above 45%. The district is located at an altitude of 768 m above sea level with the northern region higher than the south. The purpose of this study was to determine the distribution of Vs30 waves and determine the impact of damage due to wave amplification (amplification). To minimize the impact of this earthquake identification can be done including a survey to map soil characteristics in response to earthquake shocks using the seismic Horizontal to Vertical Spectral Ratio (HVSR) method. Based on the results of the study, the distribution of the dominant frequency values, Bandung Regency was identified as having hard and soft rock soil and having solid clay with a thickness of tens of meters. The amplification value in Bandung Regency has a value (0 Ao 6) which can be categorized that Bandung Regency has a small impact on the earthquake. The difference between the results of inversion processing and HVSR is due to the assumption that the layer inversion is heterogeneous and the HVSR layer is homogeneous.

scholarly journals Discrimination of earthquakes and explosions in southern Russia using regional high-frequency three-component data from the IRIS/JSP Caucasus network

1997 ◽  
Vol 87 (3) ◽  
pp. 569-588 ◽  
Author(s):  
W.-Y. Kim ◽  
V. Aharonian ◽  
A. L. Lerner-Lam ◽  
P. G. Richards
Keyword(s):  
Free Surface ◽  
High Frequency ◽  
Vertical Component ◽  
Spectral Ratio ◽  
Ratio Method ◽  
Spectral Ratios ◽  
Discrimination Power ◽  
Misclassification Probability ◽  
Southern Russia ◽  
Spectral Ratio Method

Abstract High-frequency regional records from small earthquakes (magnitude <4.5) and comparable magnitude chemical explosions are analyzed to find a reliable seismic discriminant in southern Russia near Kislovodsk. The digital, three-component seismograms recorded during 1992 by the Caucasus Network operated by Lamont-Doherty Earth Observatory since 1991 in the distance ranges 15 to 233 km are used. Mean vertical-component Pg/Lg spectral amplitude ratios in the band 8 to 18 Hz are about 1.3 and 3.2 for earthquakes and explosions, respectively, in this region. We find that the vertical-component Pg/Lg spectral ratio in the frequency band 8 to 18 Hz serves quite well for classifying these events. A linear discriminant function analysis indicates that the Pg/Lg spectral ratio method provides discrimination power with a total misclassification probability of about 7%. The Pg/Lg spectral ratios of rotated, three-component regional records improve the discrimination power of the spectral ratio method over the vertical-component Pg/Lg ratios. Preliminary analysis indicates that distance-corrected vertical-component Pg/Lg ratios improve the discrimination power by about 4% over uncorrected ratios. But we find that an even better discriminant is the Pg/Lg spectral ratio of the three-component regional records corrected for the free-surface effect. In the frequency band 8 to 18 Hz, the free-surface-corrected three-component Pg/Lg spectral ratio provides discrimination power with a total misclassification probability of only 2.6%. Free-surface-corrected and network-averaged Pg/Lg spectral ratios provide transportability of the spectral ratio method to various regions worldwide.

scholarly journals MIKROZONASI KAWASAN RAWAN BENCANA GEMPABUMI DENGAN STUDI PEAK GROUND ACCELERATION MENGGUNAKAN METODE BOORE ATKINSON DAN DATA MIKROTREMOR DI DAERAH KUPANG

2017 ◽  
Vol 1 (1) ◽  
pp. 5
Author(s):  
Rachmat Jariah Jamal ◽  
Lantu ◽  
Sabrianto Aswad ◽  
Cecep Sulaiman
Keyword(s):  
Spectral Ratio ◽  
Dominant Frequency ◽  
Tectonic Activity ◽  
Ratio Method ◽  
Eurasian Plate ◽  
Ground Acceleration ◽  
Tectonic Earthquake ◽  
Tectonic Plates ◽  
Prone Area ◽  
Dominant Period

AbstrakLetak geografis Indonesia yang berada pada pertemuan tiga lempeng tektonik utama; Lempeng Indo-Australia, Lempeng Eurasia dan Lempeng Pasifik, menjadikan Indonesia sebagai kawasan rawan gempabumi. Berdasarkan data yang dirilis oleh Direktorat Vulkanologi dan Mitigasi Bencana Geologi (DVMBG) terdapat 28 wilayah rawan gempa dan tsunami termasuk Kupang. Kupang terletak di zona busur sangat aktif dan tepian benua aktif. Kegiatan tektonik yang berlangsung saat ini dicirikan dengan kejadian gempa tektonik yang melanda daerah pedalaman, akibat dari aktifnya sesar-sesar yang terdapat di perbukitan sekitar Kota Kupang. Salah satu upaya mitigasi yang dilakukan adalah pengukuran mikrotremor menggunakan metode HVSR (Horizontal to Vertical Spectral Ratio) untuk mengetahui nilai frekuensi dominan yang akan menjadi penentu tingkat kerawanan bencana gempabumi. Nilai frekuensi dominan akan menghitung nilai kecepatan gelombang S hingga kedalaman 30 meter (Vs30) yang selanjtnya digunakan untuk menentukan nilai PGA dan amplifikasi. Hasil analisis data menunjukkan bahwa nilai periode dominan berada pada rentang 0.1-0.97 sekon, nilai PGA antara 92.87-142.84 gal dan nilai amplifikasi adalah 0.99-4.38 dan 2.12-9.43 kali. Maka dapat disimpulkan bahwa daerah penelitian termasuk kategori rawan bencana gempabumi terutama pada bagian tenggara.Kata Kunci : Amplifikasi, Mikrotremor, Periode Dominan, PGAAbstractGeographically, Indonesia located at the meeting of three major tectonic plates; Indo-Australian Plate, Eurasian Plate, and Pacific Plate, that make Indonesia as earthquake-prone area. Based on data released by the Directorate of Volcanology and Geological Hazard Mitigation (DVMBG), there are 28 earthquake and tsunami prone areas including Kupang that the area located in the very active arc zone and the edge of the active continent. The tectonic activity that is currently taking place is characterized by the tectonic earthquake that attacks to countryside areas, resulting from the active fault-faults found in the hills around the area. One of the mitigation efforts is microtremor measurement using HVSR (Horizontal to Vertical Spectral Ratio) method to find out the dominant frequency for determination of the magnitude of the earthquake. The predominant frequency value will determine the Shear wave velocity up to 30 meters (Vs30) which are further used for the PGA and amplification values. The result of data analysis shows that the dominant period value is in the range 0.1-0.97 second, PGA value between 92.87-142.84 gal and the amplification value is 0.99-4.38 and 2.12-9.43 times. The conclusion, the area is categorized as earthquake-prone, especially in the southeast region.Keywords: Amplification, Microtremor, Dominant Period, PGA

Qp-Qs relations in the sedimentary basin of the upper Mississippi Embayment using converted phases

1994 ◽  
Vol 84 (6) ◽  
pp. 1861-1868
Author(s):  
Kou-Cheng Chen ◽  
Jer-Ming Chiu ◽  
Yung-Tun Yang
Keyword(s):  
Sedimentary Basin ◽  
Vertical Component ◽  
Spectral Ratio ◽  
Unconsolidated Sediments ◽  
Ratio Method ◽  
Seismic Zone ◽  
Frequency Content ◽  
S Wave ◽  
Mississippi Embayment ◽  
Upper Mississippi Embayment

Abstract Three-component digital seismograms recorded by the 40 PANDA (Portable Array for Numerical Data Acquisition) stations in the New Madrid seismic zone were analyzed to study seismic wave attenuation in the sedimentary basin using the spectral ratio method. A prominent S-to-P (Sp) converted phase was generated at the boundary between the uppermost sedimentary basin and the underlying Paleozoic rocks. The direct S wave on the horizontal component is characterized by a lower-frequency content than that of the converted Sp wave on the vertical component. The differences in frequency content between the direct S and the Sp converted waves can be attributed to the different attenuation effects between P and S waves in the unconsolidated sediments. The spectral ratio between the low-frequency S wave and the high-frequency converted Sp wave from the bottom of the sediments can be used to yield a relationship between Qp and Qs in the sediments. Results from PANDA stations with well-constrained spectral ratios in the frequency range from 2 to 25 Hz give the Qp value ranging from 25 to 60 and Qs from 25 to 30 for the sedimentary basin in the upper Mississippi Embayment.

scholarly journals Site Response of the NARS-Baja and RESBAN Broadband Networks of the Gulf of California, México

2016 ◽  
Vol 55 (2) ◽  
Author(s):  
Lenin Ávila-Barrientos ◽  
Raúl R. Castro
Keyword(s):  
Ground Motion ◽  
Gulf Of California ◽  
Site Response ◽  
Vertical Component ◽  
Spectral Ratio ◽  
Ratio Method ◽  
S Wave ◽  
Amplification Factors ◽  
The Individual ◽  
Back Azimuth

We studied the seismic response of broadband stations located around the Gulf of California, Mexico, using the horizontal to vertical component spectral ratio method (HVSR). We analyzed 92 earthquakes recor-ded by the NARS-Baja and RESBAN networks, operated by CICESE. The database consists of events recorded between 2002 and 2006, with magnitudes ranging from 3.2 to 6.6. We rotated the records to find radial and transversal ground-motion components and we calculated Fourier spectra of S-wave windows recorded for the three ground-motion components. Then, we calculated HVSR for the individual components and the average of both horizontal components for every event. We analyze records from 20 stations located on sites with different geologic characteristics and we find azimuthal dependence on six of them that have amplification factors varying from 1.5 to up to 13 times at narrow back-azimuth ranges. We also find that sites with significant amplification factors (above three) show increasing amplification with increasing source magnitude.

scholarly journals Investigation of microtremor motion variation by Nakamura’S H/V spectral ratio method

2017 ◽  
Vol 17 (4B) ◽  
pp. 68-74
Author(s):  
Hung Nguyen - Tien ◽  
Phuong Nguyen-Hong ◽  
Minh Nguyen-Le ◽  
Wen Kuo-Liang ◽  
Nguyen Tran-An
Keyword(s):  
Data Analysis ◽  
Frequency Domain ◽  
Spectral Ratio ◽  
Dominant Frequency ◽  
Observation Time ◽  
Ratio Method ◽  
Observation Data ◽  
Frequency Range ◽  
Simultaneous Observation ◽  
Spectral Ratio Method

In this study, the variation of microtremor motion is investigated using observation data in Hanoi and Vung Tau cities. The results of observation conducted by times and by seismometers are processed using the Nakamura's H/V spectral ratio method and compared. For investigation, the observations have been conducted with frequency of 27 observations per hour, 22 observations per month, 4 simultaneous observations using both Servo and K2 seismometers, and 12 simultaneous observation using 7 Servo seismometers. The results of data analysis show that the values of dominant frequency and shapes of the H/V spectral ratio obtained are similar in the frequency range from 0.4 Hz to 5 Hz, especially on the dominant frequency domain. The results confirm that the microtremor variation observations can be carried out with one observation time or by multiple seismometers.

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