Assessment of seismic vulnerability using the horizontal-to-vertical spectral ratio (HVSR) method in Haenam, Korea

2020 ◽  
Author(s):  
Su Young Kang ◽  
Kwang-Hee Kim ◽  
Byungmin Kim
Keyword(s):  
Seismic Vulnerability ◽  
Spectral Ratio ◽  
Hvsr Method

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 Seismic Vulnerability Indices for Ground in Derince-Kocaeli (Turkey)

2021 ◽  
Author(s):  
Talih Guven
Keyword(s):  
Urban Areas ◽  
Structural Damage ◽  
Seismic Vulnerability ◽  
Active Regions ◽  
Spectral Ratio ◽  
Quick Method ◽  
Oil Refineries ◽  
Planning And Design ◽  
Hvsr Method ◽  
Ground Conditions

Abstract Derince town is one of the most densely industrialized (oil refineries, ports, etc.) and populated urban areas which is located in one of the highest seismically active regions in Turkey. The area was damaged by a severe earthquake on 17 August 1999 in Kocaeli (Mw = 7.4). The geotechnical properties of layers play the most important role in the formation of damage. One of the weakness indicators for the soil structure in a region is the ground vulnerability indices (Kg). The reduction of damage from earthquakes is related to the knowledge of these ground properties. Therefore, the microtremor horizontal-to-vertical spectral ratio (HVSR) method was applied to single site measurements at 43 stations over an area of 40 km2 to evaluate local site effects in terms of ground vulnerability indices (Kg), fundamental frequency and amplification factor. Structural damage occurring during the August 17, 1999 Kocaeli (Mw=7.4) earthquake is compared with the estimated ground vulnerability indices. The results indicate that the Kg values are in good agreement with damage distribution. Large Kg values indicate weak points in the study area. According to results, the areas with Kg values greater than 14 seem to be the most vulnerable locations in the study. The Kg and soil types overwhelmingly comply with each other very well. Poor ground conditions are seen in areas with high vulnerability. Ground conditions should be taken into account during the planning and design of urban areas. The results obtained by considering ground conditions can be used as a quick method to identify risky areas.

scholarly journals Studi Mikrotremor dengan Metode Horizontal to Vertical Spectral Ratio (HVSR) di Tapak RDE, Serpong

EKSPLORIUM ◽  
2019 ◽  
Vol 40 (2) ◽  
pp. 105
Author(s):  
Eko Rudi Iswanto ◽  
Yuni Indrawati ◽  
Theo Alvin Riyanto
Keyword(s):  
Seismic Vulnerability ◽  
Nuclear Reactor ◽  
Amplification Factor ◽  
Power Reactor ◽  
Spectral Ratio ◽  
Vulnerability Index ◽  
Historical Records ◽  
Hvsr Method ◽  
Subsurface Investigation ◽  
Selection For

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.

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 Potentials and pitfalls of permafrost active layer monitoring using the HVSR method: A case study in Svalbard

2018 ◽  
Author(s):  
Andreas Köhler ◽  
Christian Weidle
Keyword(s):  
Active Layer ◽  
Spectral Ratio ◽  
Time Lapse ◽  
Careful Analysis ◽  
Temporal Variations ◽  
Soil Conditions ◽  
Seismic Velocities ◽  
Essential Information ◽  
Hvsr Method ◽  
Changing Noise

Abstract. Time-lapse monitoring of the sub-surface 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 thawn 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 sub-surface 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 sub-surface. 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. In addition, we investigate if effects of changing noise sources on HVSRs can be avoided by utilizing a directional, narrow-band (4.5 Hz) repeating seismic tremor which is observed at the permanent seismic broadband station KBS 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 thawn active layer with very low seismic velocities would affect Rayleigh wave ellipticities in the tremor frequency band.

Estimation of Site Dynamic Characteristics from Ambient Noise Measurements Using HVSR Method in Microzonation Study: Senggarang, Batu Pahat, Malaysia

2014 ◽  
Vol 931-932 ◽  
pp. 803-807 ◽  
Author(s):  
Ahmad Fahmy Kamarudin ◽  
Mohd Effendi Daud ◽  
Zainah Ibrahim ◽  
Ibrahim Azmi ◽  
Mohamad Khairani Yub ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Ambient Noise ◽  
Hazard Analysis ◽  
Resonance Effect ◽  
Spectral Ratio ◽  
Boundary Area ◽  
Contour Maps ◽  
The North ◽  
Hvsr Method ◽  
Noise Measurements

Site dynamic characteristics evaluation of fundamental ground frequency, Fo and amplification factor, Ao in Senggarang region were presented in 2D and 3D contour maps (microzonation maps) based on the ambient noise measurements carried out using Lennartz 1 Hz tri-axial seismometer sensors. Reliability of Fo and Ao determined from the ambient noise technique has become the main key components in seismic hazard analysis, resonance effect assessment, predictions of sedimentary layer and shear wave velocity, through cheaper, non-destructive and quick methodology. 73 points of ambient noise records were analyzed using Horizontal-to-Vertical Spectral Ratio (HVSR) method in the boundary area of 800 m x 800 m with the grid spacing of 100 m x 100 m. Significant peaks of mean HVSR curves were checked against the criterions proposed by the SESAME guideline. Slight difference of the Fo contours pattern between the North-South (NS) and the East-West (EW) directions was observed, but vice versa to the Ao contours between both directions. Significant peaks of Fo values were distributed from 1.61 to 6.35 Hz, whereas the Ao values were found from 3.18 to 9.39. Wide gap between the ranges of Fo and Ao in respective direction have shown to the variation of sediment thicknesses. Meanwhile, dominance shape of significant peak from the HVSR curves may indicate to a large velocity contrast presence underneath the ground surfaces.

scholarly journals Mikrozonasi di Daerah Plampang, Nusa Tenggara Barat

EKSPLORIUM ◽  
2021 ◽  
Vol 42 (1) ◽  
pp. 39
Author(s):  
Eko Rudi Iswanto ◽  
Theo Alvin Riyanto ◽  
Hadi Suntoko
Keyword(s):  
Seismic Vulnerability ◽  
Volcanic Rocks ◽  
Spectral Ratio ◽  
Vulnerability Index ◽  
Tectonic Activity ◽  
Analysis Method ◽  
The North ◽  
Vulnerability Maps ◽  
Vulnerability Map ◽  
Microtremor Measurement

ABSTRAK Provinsi Nusa Tenggara Barat (NTB) merupakan daerah dengan aktivitas kegempaan yang tinggi. Fenomena ini disebabkan oleh adanya aktivitas tektonik sebagai akibat pertemuan Lempeng Eurasia-Australia (zona subduksi) di bagian selatan dan Sesar Flores di bagian utara serta adanya keberadaan sesar-sesar lokal. Terkait dengan rencana pengembangan kawasan Samota di Pulau Sumbawa, NTB, perlu dilakukan suatu kajian kegempaan. Tujuan penelitian ini adalah memetakan indeks kerentanan seismik (Kg) melalui pengukuran mikrotremor dengan analisis menggunakan metode Horizontal to Vertical Spectral Ratio (HVSR). Hasil penelitian berupa peta kerentanan seismik daerah Plampang yang menunjukkan bahwa sisi utara lokasi penelitian memiliki indeks kerentanan seismik rendah yang ditandai dengan nilai amplifikasi kurang dari tiga jika dibandingkan daerah lainnya. Geologi sisi utara lokasi penelitian tersusun oleh batuan gunung api dengan karakteristik batuan keras, ketebalan sedimen sangat tipis, dan tersusun atas batuan Tersier atau lebih tua. Peta kerentanan seismik berguna sebagai acuan dalam mitigasi gempa bumi untuk mengurangi risiko yang ditimbulkan. ABSTRACT Nusa Tenggara Barat (NTB) Province is an area with intense seismic activity. This phenomenon is caused by tectonic activity as the result of the convergency of the Eurasia-Australia Plates (subduction zone) in the south and the Flores Fault in the north as well as the presence of local faults. Regarding the plan to develop the Samota area in Sumbawa Island, NTB, a study concerning earthquakes should be done. The purpose of this study is to map the seismic vulnerability index (Kg) through microtremor measurement by using the Horizontal to Vertical Spectral Ratio (HVSR) analysis method. The result of the study is a seismic vulnerability map of the Plampang area which its northern part has a low seismic vulnerability index indicated by the amplification factor value of less than three compared to other areas. The geology of the northern part of the Plampang area consists of volcanic rocks which has hard rock characteristic, very thin sediment thickness, and composed of Tertiary or older rocks. Seismic vulnerability maps can be useful as a reference for earthquake mitigation to reduce its risks.

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