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

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.

2018 ◽  
Vol 2 (2) ◽  
pp. 66-74
Author(s):  
Roswita T. Saman ◽  
Hery L. Sianturi ◽  
Redi K. Pingak

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


2014 ◽  
Vol 896 ◽  
pp. 521-524 ◽  
Author(s):  
Muhammad Farid ◽  
Kirbani Sri Brotopuspito ◽  
Wahyudi ◽  
Sunarto ◽  
Wiwit Suryanto

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.


2021 ◽  
Vol 873 (1) ◽  
pp. 012005
Author(s):  
Robert Edison ◽  
Supriyanto Rohadi ◽  
Yusuf Perdana ◽  
Nelly Florida Riama ◽  
Dwikorita Karnawati

Abstract Seismic vulnerability index is one of the key factors in mitigation that shows the vulnerability of the soil layer beneath when passed through with a wave, the more vulnerable the soil layer, the more damage it done when an earthquake happens. Seismic vulnerability is calculated using two variables, that is dominant frequencies and amplification that are obtained by analyzing HVSR curve. HVSR are used to determine the dominant frequency by determining the maximum amplification in that area. HVSR curve is obtained by measuring microbemor data in 163 spots with 30 minutes-minimum duration in Cilacap with a portable seismograph. Mierotremor is a natural vibration that is caused by continuous vibration that come from beneath the surface, sometimes mixed up by the vibrabon that is caused by human activities such as pipe-flow, vehicles, etc. Thus, the purposes of this research are to determine which area is more vulnerable than others, based on the seismic vulnerability index, so it could be a reference for regional development to classified is it safe or unsafe to build in that area, remembering Cilacap is one of the most developed Districts in Central Java.


2018 ◽  
Vol 2 (2) ◽  
pp. 50-57
Author(s):  
Ida Nubatonis ◽  
Hery L. Sianturi ◽  
Bernandus Bernandus

ABSTRAK Telah dilakukan penelitian tentang mikrozonasi seismik dengan metode HVSR di Desa Lili Kecamatan Fatuleu Kabupaten Kupang. Tujuan dari penelitian ini adalah mengetahui nilai frekuensi dominan tanah, amplifikasi, indeks kerentanan seismik dan percepatan tanah maksimum. Penelitian dilakukan dengan menggunakan TDS tipe 303 dengan frekuensi natural 0,2Hz-20Hz. Berdasarkan hasil penelitian, didapatkan bahwa nilai frekuensi dominan berkisar antara 0,279 Hz-17,210Hz, nilai amplifikasi berkisar antara 1,802-10,240 dan nilai indeks kerentanan seismik berkisar antara 0,422-421,167. Nilai percepatan tanah maksimum berkisar antara 160,769 gal – 279,316 gal dengan tingkat resiko besar dua dan tingkat resiko besar tiga. Kata kunci: Mikrozonasi, HVSR, Lili ABSTRACT The research about seismik microzonation using HVSR methods in Lili village, sub-district of Fatuleu, district of Kupang has been done. The aims of this research are to determine the values of soil dominant frequency, magnitude of amplification, seismik vulnerability index, and the peak ground acceleration. This research used TDS 303S type with0,2Hz-20Hz of natural frequency. According to this research, it was obtained that the values of the dominant frequency was about 0,279Hz-17,210Hz, the amplification values were found to be 1,802-10,240 and the index of vulnerability has values about 0,422-421,167. The peak ground acceleration values about 160,769 gal – 279,316 gal with great risk level two and great risk level three. Keywords: microzonation, HVSR, Lili


2020 ◽  
Vol 24 (2) ◽  
pp. 66
Author(s):  
Ayu Syahputri ◽  
Sismanto Sismanto

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.


2020 ◽  
Vol 11 (2) ◽  
pp. 1-25
Author(s):  
Shiv Shankar Kumar ◽  
Pradeep Acharya ◽  
Pradeep Kumar Dammala ◽  
Murali Krishna Adapa

This chapter presents the seismic vulnerability of Kathmandu City (Nepal), based on Nepal 2015 earthquake, in terms of the ground response and liquefaction potential. The spatially well-distributed 10-boreholes and ground motions of Mw 7.8 Nepal 2015 earthquake recorded at five different stations were adopted for the analysis. The range of peak ground acceleration and peak spectral acceleration were in the order of 0.21g-0.42g and 0.74g-1.50g, respectively. Liquefaction potential of the sites were computed using both semi-empirical approach and liquefaction potential index (LPI). LPI shows that the 6 sites out of 10 sites are at high risk of liquefaction.


2020 ◽  
Vol 15 (1) ◽  
pp. 9-19
Author(s):  
Santiago Pujol ◽  
Lucas Laughery ◽  
Aishwarya Puranam ◽  
Pedram Hesam ◽  
Li-Hui Cheng ◽  
...  

Communities need seismic vulnerability indices to identify which buildings are most susceptible to severe damage during earthquakes. To be of greatest value, these indices should be easy to use and should be vetted against data from previous earthquakes. To date, more than 800 reinforced concrete buildings have been surveyed after earthquakes for the purpose of evaluating a seismic vulnerability index proposed by Hassan and Sozen in 1997. This number includes 130 buildings surveyed after the 6 February 2016 earthquake in Taiwan. The data collected during these surveys consist of descriptions and photographs of damage, structural sketches, and measurements. Analyses of the data indicate that probability of severe damage and failure increases with decreasing column index and wall index (normalized measures of column and wall areas). They also suggest that the exact form of the threshold used to distinguish more vulnerable structures from less vulnerable structures is of little consequence in terms of the probable cost and benefits of the strengthening program this threshold may inform.


2019 ◽  
Vol 3 (2) ◽  
pp. 60
Author(s):  
Urip Nurwijayanto Prabowo ◽  
Ayu Fitri Amalia ◽  
Widodo Budhi

Watukumpul is located in Pemalang District, Central Java, which is adjacent to the fault seismotectonic line of Baribis fault in the north and subduction area of the Eurasian and Indies-Australian plates in the south. It makes Watukumpul often experiences an earthquake. This study aimed to map the peak ground acceleration calculated using the Kanai equation and earthquake intensity calculated using Wald equations in Watukumpul. This study used historical earthquake data occurred in 1988-April 2018 from the International Seismological Center and microtremor measurements of 33 points. Microtremor data were processed using the Horizontal to Vertical Spectral Ratio method and resulted the predominant period of study area ranged from 0.13 to 0.74 s. The results showed that the study area had a PGA value of 26.93 - 63.25 gal. The intensity calculation showed that the study area has the potential for earthquake damage with an III-IV MMI scale. Keywords: Kanai, Watukumpul, Intensity, Earthquake


2020 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Rahmat Setyo Yuliatmoko

The Tasikmalaya M 7.3 earthquake on September 2, 2009 had an impact on Garut, damaged infrastructure and claimed many lives. From the search results there were five areas that were severely damaged by tectonic earthquake shocks, which included Pemeungpeuk, Cisompet, Cikelet, Peundeuy and Banjarwangi Subdistricts, so that earthquake mitigation measures were needed. One of the mitigations that can research how the impact is if the potential for earthquake disasters occur below the southern surface of Java. The final objective of this research is to map disaster-prone zones in Tarogong Kaler, Tarogong Kidul, Garut City, and Karang Pawitan, Garut Subdistrict, based on dominant frequency values, Vs30, seismic vulnerability indexes, and GSS (Ground Shear Strains) so that they can know the land movement that is. Retrieval of data in this study by measuring geophysicaly methods in the field. Processing data using HVSR (Horizontal to Vertical Spectra Ratio) method, then mapped with ArcGis to interpret the zoning of the study area. Based on the research, we known that the dominant frequency distribution value is between 1-5.2 Hz. The seismic vulnerability index values calculated the study area are between 3 – 45, GSS values in the study area between 3 ×10-4 - 42×10-4. By looking at the spatial distribution of the values of f0, Kg and GSS the areas of Karangmulya, Jatiasih, Sidanggalih and Godog villages are types of young volcanic sediments classified as soft soils that are easily to wave amplification and earthquake vibrations, so that they are easily damaged during large earthquakes. in this region qualify as earthquake resistant buildings to minimize damage and losses, while Sukabakti, Kersamenak, Sukajaya, and Mekargalih villages in the west with the geological conditions of the surrounding area which is hard land so that it will be safer when an earthquake occurs.


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