scholarly journals Ground Shear Strain and Rate of Erosion in the Coastal Area of North Bengkulu, Indonesia

2014 ◽  
Vol 896 ◽  
pp. 521-524 ◽  
Author(s):  
Muhammad Farid ◽  
Kirbani Sri Brotopuspito ◽  
Wahyudi ◽  
Sunarto ◽  
Wiwit Suryanto
Keyword(s):  
Shear Strain ◽  
Coastal Area ◽  
Erosion Rate ◽  
Seismic Vulnerability ◽  
Sandy Beach ◽  
Vulnerability Index ◽  
Sandy Beaches ◽  
Ground Acceleration ◽  
Short Period ◽  
Rocky Coast

North Bengkulu district has an area prone to earthquakes, because this area is very closed to the Sumatra subduction zone to the Eurasian tectonic plate. Coastal area in this region is experiencing with the very fast erosion. This is thought to have relation with earthquake-prone zones. This study aims to find the relationship between Ground Shear Strain (GSS) and rate of erosion in the coastal area of North Bengkulu. The data of coastal erosion rate was obtained by overlaying shoreline in 1947 and 2012. The GSS can be obtained by multiplying Seismic Vulnerability Index (SVI) and Peak Ground Acceleration (PGA) values around the shoreline. Seismic Vulnerability Index was obtained by processing microseismic data acquired using three component in short period of seismometers. The PGA was obtained from the historical earthquake and calculated by using Fukushima-Tanaka equation. The results show that the value of GSS varies between 0.0001 to 0.0055, and the SVI values is ranging from 1.2 to 16.1. In addition, we estimated that PGA value is 92 to 120 and the rate of erosion between 3.6 up to 5.8 m/yr. GSS value for each type of coastal is 0.00046 for the fine sandy beach flat, 0.0043 for flat coastal muddy, 0.0001 for flat rocky beaches, 0.0006 for sandy beaches to rugged, 0.0003 for steep rocky lava beach, 0.0014 for steep rocky coast of for clay, 0.0011 for bertufa steep sandy beach stones, and 0.0014 for the steep rocky shore tuffaceous clay. It is found that the GSS value depends on the type of coastal. In this case, flat coastal muddy show highest effect on the GSS. Both SVI and GSS can be estimated to be a quadratic relation to the erosion rate.

scholarly journals Interpretation of Dynamic Sediment Characteristic Based on Microtremor Analysis in Prambanan Region, Sleman Yogyakarta and Klaten Central Java, Indonesia

2018 ◽  
Vol 16 (1) ◽  
pp. 9 ◽  
Author(s):  
Hesti Hesti ◽  
Subagyo Pramumijoyo ◽  
Djoko Wintolo
Keyword(s):  
Shear Strain ◽  
Peak Ground Acceleration ◽  
Seismic Vulnerability ◽  
Vulnerability Index ◽  
Dominant Frequency ◽  
Severe Damage ◽  
Ground Acceleration ◽  
Central Java ◽  
Using Data ◽  
Very High

Yogyakarta earthquake on Mei 27, 2006 caused Prambanan area get quite severe damage marked by damageof resident house and Prambanan Temple.This study was conducted using data of microtremorsingle station and Yogyakarta earthquake 27 May 2006. Data were analyzed with microtremor HVSR methods to get the value of the dominant frequency (fo) and amplication (Ao).Furthermore, calculated the value of peak ground acceleration (PGA) in the layers of sedimen bedrock and seismic vulnerability index (Kg) to get ground shear strain value. Prambanan area has a dominant frequency (fo) value ranges from 0.63-6.78 Hz. Ground shear strain valueranges from 3,55.10-5 - 4,04.10-2.Each of these factors is then mapped with a division of 4 zones is very high, high, medium, and low.Based on the analysis of all these factors Prambanan area is an area that is vulnerable to the risk of earthquake events.

scholarly journals Analysis of H/V Ratio Curve to Estimate Seismic Hazard Vulnerability in Lombok Island, West Nusa Tenggara, Indonesia

2020 ◽  
Vol 18 (1) ◽  
pp. 1
Author(s):  
Muhammad Randy Caesario Harsuko ◽  
Zulfakriza Z. ◽  
Andri Dian Nugraha ◽  
Muzli Muzli ◽  
David Prambudi Sahara ◽  
...  
Keyword(s):  
Seismic Vulnerability ◽  
Vertical Component ◽  
Horizontal Component ◽  
Geological Condition ◽  
Predominant Frequency ◽  
Particle Movement ◽  
Ground Acceleration ◽  
Short Period ◽  
Component Spectrum ◽  
Lombok Island

In 2018, Lombok Island was hit by a series of destructive earthquakes. According to Indonesian Meteo- rological, Climatological, and Geophysical Agency data, about 1,973 felt earthquakes (M > 3) which shaken Lombok were recorded during August 2018 with three earthquakes with the largest magnitude of 6.9 Mw, 6.8 Mw, and 6.2 Mw. National Board for Disaster Management reported about 555 deaths, 1,833 people injured, and 186,010 houses damaged as a result of Lombok earthquake on August 5th, 2018. A number of seismometers were placed on Lombok Island from August 3rd, 2018 to October 19th, 2018 to monitor the aftershock events. There are 17 stations that record seismicity in Lombok consisting of 10 broadband sensors and 7 short period sensors. In this study, we used the Horizontal-to-Vertical Spectral Ratio (HVSR) method to analyze the risk of earthquake in the Lombok region. The basic concept of this method is to do a comparison between the horizontal component spectrum and the vertical component spectrum of a wave, where theoretically the particle movement of the horizontal component is greater than the particle movement of the vertical component on soft ground, whereas on the hard ground both components (horizontal and vertical) will be similar. H/V curve obtained from earthquake record- ings (Earthquake Horizontal-to-Vertical Ratio/EHVR) and H/V curve obtained from microtremor recordings (Microtremor Horizontal-to-Vertical Ratio/MHVR) shows good agreement and high correlation. Empirical correction of EMR (Earthquake-to-Microtremor Ratio) managed to decrease the difference of estimation of predominant frequency and amplification factor between EHVR and MHVR. Predominant frequency, amplification, and seismic vulnerability map agree with the geological condition of Lombok Island, where high value of amplification and seismic vulnerability was found on soft and thick ground. This study conclude that the maximum ground acceleration and the construction of the building should also considered when one wants to investigate the effect of an earthquake to the damage occurred, beside the site effects.

scholarly journals THREE-DIMENSIONAL MORPHODYNAMIC MODEL TO SANDY BEACH WITH NON-ERODED HARD BOTTOM

2012 ◽  
Vol 1 (33) ◽  
pp. 10
Author(s):  
Yukihiko Hasegawa ◽  
Masamitsu Kuroiwa ◽  
Yuhei Matsubara ◽  
Yasushi Icimura ◽  
Yoshiyuki Nagaishi
Keyword(s):  
Suspended Sediment ◽  
Diffusion Model ◽  
Coastal Area ◽  
Sandy Beach ◽  
Suspended Sediment Concentration ◽  
Three Dimensional ◽  
Sediment Concentration ◽  
Sandy Beaches ◽  
Model Tests ◽  
And Diffusion

The objective of study is to develop a coastal area model for sandy beach with shore reef such as non-eroded hard bottom. The morphodynamics with exposure and bury of the shore reef are reproduced by advection and diffusion model for suspended sediment concentration. Firstly, model tests associated with sandy beaches with a detached breakwater and groins were carried out in order to investigate the performance of the presented model. Secondly, the presented model was applied to a filed site with both shore reef and sandy beach, the applicability of the model was investigated and discussed.

scholarly journals Analysis of Earthquakes Potential Damages as a Disaster Mitigation Effort

2021 ◽  
Vol 2 (1) ◽  
pp. 20-23
Author(s):  
Alen Fezi Loveka ◽  
Henny Johan ◽  
Rendy W. Wardana
Keyword(s):  
Shear Strain ◽  
Seismic Vulnerability ◽  
Vulnerability Index ◽  
Disaster Mitigation ◽  
Sediment Layer ◽  
Residential Areas ◽  
Literature Study ◽  
Geological Conditions ◽  
Potential Damage ◽  
Mitigation Effort

Muara Bangkahulu District is one of Bengkulu Province Subdistricts, which is used as a place for higher education service centers, government office centers, and community residential areas. Muara Bangkahulu has the risk of being affected by an earthquake caused by its geological conditions. To avoid the potential damage due to earthquake, the PGA parameters, seismic vulnerability index, ground shear strain, and thickness of sediment layer (h) were analyzed in Muara Bangkahulu District as an effort to mitigate earthquakes. The purpose of this study is to describe the potential damage caused by the earthquake in Muara Bangkahulu District as a disaster mitigation effort. This research was a qualitative descriptive study using the literature study method. The results of the literature study which showed the value of PGA produced between 184.22 gal to 532.92 gal. Distribution of seismic vulnerability index values between 0.56 to 7.95. Distribution of ground shear strain values between 5.14 x10-5 to 7.42 x10-4. The thickness of the sediment layer (h) ranged from 8.13 meters to 61.31 meters. The largest PGA, IKS, GSS and h values are in Kualo Beach which is estimated to have a high level of risk for earthquake disasters with a correlation more than 74%. Thus, it can be concluded that the vicinity of Kualo Beach is the most potential and prone to earthquake damage.

scholarly journals PEMETAAN MIKROZONASI SEISMIK DI DESA NUNKURUS KECAMATAN KUPANG TIMUR KABUPATEN KUPANG

2018 ◽  
Vol 2 (2) ◽  
pp. 66-74
Author(s):  
Roswita T. Saman ◽  
Hery L. Sianturi ◽  
Redi K. Pingak
Keyword(s):  
Peak Ground Acceleration ◽  
Seismic Vulnerability ◽  
Single Point ◽  
Vulnerability Index ◽  
Dominant Frequency ◽  
Seismic Microzonation ◽  
Ground Acceleration ◽  
Index Value ◽  
Frequency Magnitude

ABSTRAK  Telah dilakukan penelitian mikrozonasi seismik di desa Nunkurus Kecamatan Kupang Timur Kabupaten Kupang. Penelitian ini bertujuan untuk mengetahui  nilai frekuensi dominan tanah, nilai ampifikasi, indeks kerentanan tanah dan percepatan tanah serta membuat peta indeks kerentanan tanah dan peta. Berdasarkan hasil penelitian diperoleh nilai frekuensi dominan tanah berkisar antara 0.293 Hz – 18.41 Hz, nilai amplifikasi berkisar antara 1,68–8,52, nilai indeks kerentanan seismik  berkisar antara 0,3285 –179,23556 dan nilai PGA berkisar antara 107,77488 gal-218,62941 gal sehingga dapat dikatakan bahwa daerah penelitian berada dalam kawasan yang cukup aman karena hanya sebagian titik saja yang memiliki nilai frekuensi, nilai amplifikasi, nilai indeks kerentanan dan nilai PGA yang besar. Kata kunci : Mikrozonasi, HVSR, Nunkurus  ABSTRACT  The research about seismic microzonation in Nunkurus village, sub-district of east Kupang, district of Kupang has been done. The aims of this research are to determine the values of soil dominant frequency, magnitude of amplification, seismic vulnerability index, the peak ground acceleration and to make seismic vulnerability index map and PGA map. The results showed that the values of the the values of the dominant frequency was about 0,293 Hz – 18,41 Hz, the amplification about 1,68 – 8,52. Meanwhile, the index of vulnerability was found to be 0,32853 – 179,23556  and peak ground acceleration values about 107,77488 gal - 218,62941 gal so it can be said that the area of ​​research is safe enough because only a single point that has the frequency value, the value of amplification, the index value of vulnerability and PGA great value. Keywords : Microzonation, HVSR, Nunkurus

scholarly journals ANALISIS KERENTANAN PANTAI MENGGUNAKAN COASTAL VULNERABILITY INDEX (CVI) DI WILAYAH PESISIR TANJUNG PANDAN, KABUPATEN BELITUNG

2018 ◽  
Vol 7 (4) ◽  
pp. 298-306
Author(s):  
Anditya Devi Rachmadianti ◽  
Frida Purwanti ◽  
Nurul Latifah
Keyword(s):  
High Activity ◽  
Coastal Area ◽  
Sandy Beach ◽  
Secondary Data ◽  
Vulnerability Index ◽  
Shoreline Erosion ◽  
Coastal Vulnerability ◽  
Coastal Vulnerability Index ◽  
Medium Level ◽  
Coastal Damage

Wilayah pesisir Tanjung Pandan terdiri atas Kelurahan Air Saga, Tanjung Pendam dan Kampung Parit dan merupakan pusat ibukota Pulau Belitung. Tingginya kegiatan perikanan dan aktivitas manusia di wilayah ini menyebabkan perlunya kajian mengenai analisis kerentanan pantai guna melakukan upaya pencegahan kerusakan pantai dan pengelolaan wilayah pantai secara berkelanjutan. Tujuan dari penelitian ini adalah untuk mengetahui tingkat kerentanan dan lokasi kerentanan pantai yang paling tinggi serta variabel yang paling berpengaruh terhadap kerentanan pantai. Penelitian ini dilaksanakan pada bulan Mei 2018 dengan menganalisis variabel geomorfologi, erosi/akresi, kemiringan pantai, jarak tumbuhan dari pantai, pasang surut dan tinggi gelombang sesuai dengan indeks kerentanan pantai. Metode pengambilan data lapangan dilakukan melalui pengamatan secara langsung dengan pembagian sel pantai sebanyak 7 sel serta berdasarkan data sekunder. Hasil penelitian menunjukkan bahwa nilai CVI sel pantai 1-5 dan 7 tergolong kategori kerentanan rendah dengan nilai CVI berkisar antara 14,43 – 20,41, sedangkan sel pantai 6 tergolong kategori kerentanan menengah dengan nilai CVI 22,82. Lokasi kerentanan paling tinggi berada pada sel pantai 6 dengan kondisi geomorfologi pantai pasir serta paling dipengaruhi oleh variabel perubahan garis pantai akibat terjadinya peristiwa erosi. Tanjung Pandan Coastal Area consists of Air Saga, Pendam Cape and Kampung Parit region that are the centre of Belitung Island. The high activity of human and fisheries in the area cause the coastal vulnerability that need to be examined to prevent coastal damage and to manage the coastal area in a sustainable way. This study was conducted in May 2018 by analyzing geomorphology, shoreline erosion/accretion, coastal slope, plants distance from the coast, mean tide range and mean wave height based on coastal vulnerability index within direct observation at seven coastal cells and based on secondary data. The research showed that the CVI value on the 1st – 5th cells and the 7th cell categorized at low level with a range between 14,43 – 20,41, while the 6th cell categorized at medium level with the CVI value 22,82. The highest vulnerability located on the 6th cell with a sandy beach geomorphology and most affected by coastline changes variable due to the occurrence of erosion.  

scholarly journals The updated zonation of Seismic Vulnerability Index and ground shear strain at Bengkulu City, Indonesia

2021 ◽  
Author(s):  
Nanang Sugianto ◽  
Refrizon ◽  
Lindung Zalbuin Mase ◽  
Sherli Anggeraini
Keyword(s):  
Shear Strain ◽  
Seismic Vulnerability ◽  
Vulnerability Index

scholarly journals Fragility curves for Italian URM buildings based on a hybrid method

2021 ◽  
Author(s):  
A. Sandoli ◽  
G. P. Lignola ◽  
B. Calderoni ◽  
A. Prota
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Limit State ◽  
Ultimate Limit State ◽  
Masonry Building ◽  
Masonry Buildings ◽  
Seismic Behaviour ◽  
Building Stock ◽  
Ground Acceleration ◽  
Damage Scenario

AbstractA hybrid seismic fragility model for territorial-scale seismic vulnerability assessment of masonry buildings is developed and presented in this paper. The method combines expert-judgment and mechanical approaches to derive typological fragility curves for Italian residential masonry building stock. The first classifies Italian masonry buildings in five different typological classes as function of age of construction, structural typology, and seismic behaviour and damaging of buildings observed following the most severe earthquakes occurred in Italy. The second, based on numerical analyses results conducted on building prototypes, provides all the parameters necessary for developing fragility functions. Peak-Ground Acceleration (PGA) at Ultimate Limit State attainable by each building’s class has been chosen as an Intensity Measure to represent fragility curves: three types of curve have been developed, each referred to mean, maximum and minimum value of PGAs defined for each building class. To represent the expected damage scenario for increasing earthquake intensities, a correlation between PGAs and Mercalli-Cancani-Sieber macroseismic intensity scale has been used and the corresponding fragility curves developed. Results show that the proposed building’s classes are representative of the Italian masonry building stock and that fragility curves are effective for predicting both seismic vulnerability and expected damage scenarios for seismic-prone areas. Finally, the fragility curves have been compared with empirical curves obtained through a macroseismic approach on Italian masonry buildings available in literature, underlining the differences between the methods.

scholarly journals Earthquake and tsunami potential levels in Sulawesi (lesson learned earthquake West Sulawesi)

2021 ◽  
Vol 331 ◽  
pp. 07005
Author(s):  
Rio Khoirudin Apriyadi ◽  
Sobar Sutisna ◽  
Lasmono ◽  
Riskina Tri Januarti
Keyword(s):  
Seismic Vulnerability ◽  
Descriptive Analysis ◽  
Secondary Data ◽  
Soil Classification ◽  
Vulnerability Index ◽  
Tsunami Waves ◽  
Earthquake Resistant ◽  
Negative Impacts ◽  
Recovery Program ◽  
Post Disaster

Earthquake and tsunami disasters always bring negative impacts and losses for humans. The high frequency of earthquake disasters in Sulawesi and the massive impact of destruction and damage to infrastructure, loss of homes and property, and death of people are partly due to the lack of knowledge of this potential disaster by the surrounding community. Therefore, it is necessary to study the potential for earthquake and tsunami disasters on Sulawesi Island, and Lesson Learned about the Earthquake Disaster that has occurred in past. This study uses a qualitative method with a descriptive analysis design of secondary data obtained through a comprehensive literature review. The results showed that Sulawesi Island has a high potential for earthquake disasters, which is in the historical records of disasters, some of these earthquakes were accompanied by tsunami waves. The lesson that can be drawn from the earthquake in West Sulawesi is the potential for aftershocks after the opening earthquake and the main earthquake. In addition, the urgency of building earthquake-resistant housing structural mitigation is the key to safety during an earthquake. The post-earthquake recovery program in West Sulawesi requires further studies related to soil classification surveys, soil dominant periods, and soil seismic vulnerability index, as part of rebuilding a better and safer post-disaster area.

scholarly journals Identifikasi Potensi Tanah Longsor Menggunakan Metode Mikrotremor Di Dusun Tegalsari Desa Ngargosari Kecamatan Samigaluh Kabupaten Kulon Progo

2020 ◽  
Vol 24 (2) ◽  
pp. 66
Author(s):  
Ayu Syahputri ◽  
Sismanto Sismanto
Keyword(s):  
Shear Strain ◽  
Peak Ground Acceleration ◽  
Spectral Ratio ◽  
Ground Acceleration

Tanah longsor adalah bencana alam yang sering terjadi di Indonesia. Banyak faktor yang menyebab tanah longsor terjadi antara lain curah hujan yang tinggi, topografi yang curam, lapisan sedimen yang tebal dan pergerakan tanah. Salah satu daerah yang sering mengalami tanah longsor adalah Kecamatan Samigaluh. Oleh karena itu, pengambilan data mikrotremor dilakukan di Dusun Tegalsaari Desa Ngargosari Kecamatan Samigaluh Kabupaten Kulon Progo Daerah Istimewa Yogyakarta untuk mengetahui nilai frekuensi dominan dan amplifikasi di daerah tersebut yang diperoleh dari metode Horizontal to Vertical Spectral Ratio (HVSR). Selanjutnya, nilai frekuensi dominan dan amplifikasi diolah untuk mengetahui indeks kerentanan seismik, ketebalan lapisan sedimen, peak ground acceleration dan ground shear strain yang digunakan untuk mengetahui daerah yang berpotensi mengalami tanah longsor. Berdasarkan hasil analisis data mikrotremor diperoleh nilai frekuensi dominan antara 2,1 Hz – 18,7 Hz, nilai amplifikasi berkisar antara 1,4 sampai 8,1, indeks kerentanan seismik antara 0,27 – 26,04 s2/cm, nilai PGA berkisar antara 81,36  – 245,42 gal, ground shear strain antara 2,39 x 10-5 – 2,30 x 10-3 dan ketebalan sedimen berkisar antara 9,06 – 89, 55 meter. Daerah dengan potensi tanah longsor yang tinggi ditentukan dengan menganalisis persebaran nilai amplifikasi, indeks kerentanan seismik, ketebalan lapisan sedimen, peak ground acceleration, dan ground shear strain sehingga diperoleh daerah yang memiliki potensi tanah longsor tinggi berada di area 16, 46, 92, 100, 101, 103, 104, 105, 113, dan 114.

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