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An Estimation of Earthquake Impact to Population in Makassar by Probabilistic Approach Sunardi, Bambang; Sulastri, Sulastri
Forum Geografi Vol 30, No 2 (2016): December 2016
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/forgeo.v30i2.2591

Abstract

Makassar is one of Indonesian big cities with rapid growth rate, but not totally safe from earthquake hazard. This condition led study on affected population by earthquakes in this city are important to do. This paper estimated the population of Makassar City threatened by the probabilistic earthquake hazard. In this current study, earthquake hazard in the forms of peak ground acceleration (PGA) and spectral acceleration,  estimated by using Probabilistic Seismic Hazards Analysis (PSHA). The PSHA result then overlaid with administration map and population data to obtain distribution and percentage of population threatened by the probabilistic earthquake hazard. The results showed the smallest value of ground acceleration located in the south-west (Tamalate sub district), further north increased and reached the highest value in the northeast (Biring Kanaya sub district). Both Tamalate and Biringkanaya can be classified as rural area with low population density.  The urban area of Makassar, which is the concentration of population, located in the centre of Makassar, got the middle earthquake hazard.
Variasi Gas Radon dan Aktivitas Kegempaan di Sekitar Patahan Opak Sunardi, Bambang
Jurnal Lingkungan dan Bencana Geologi Vol 9, No 1 (2018)
Publisher : Badan Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2498.195 KB) | DOI: 10.34126/jlbg.v9i1.166

Abstract

Monitoring gas radon di dalam tanah telah dilakukan secara kontinyu selama dua tahun terakhir di sekitar patahan Opak Yogyakarta sebagai salah satu upaya mitigasi bencana gempa. Penelitian ini bertujuan menganalisis variasi radon dan aktivitas kegempaan yang terjadi di sekitar patahan Opak serta mengeksplorasi munculnya prekursor untuk gempa lokal. Monitoring data radon dilakukan di dua lokasi yaitu di daerah Pundong dan Piyungan, sedangkan aktivitas gempa di sekitar patahan Opak diperoleh dari data repositori gempabumi BMKG.  Eksplorasi anomali radon untuk melihat adanya prekursor gempa dilakukan dengan menerapkan metode korelasi. Anomali radon ditetapkan apabila rasio simpangan koefisien korelasi (Sk) dengan deviasi standar (Ds) lebih kecil dari -1.  Hasil penelitian menunjukkan peningkatan emisi gas radon berkorelasi dengan kenaikan frekuensi kejadian gempa. Penerapan metode korelasi memperlihatkan beberapa anomali radon yang dapat diklasifikasikan sebagai prekursor gempa di sekitar patahan Opak. Penelitian lebih lanjut diperlukan untuk melihat konsistensi hasil monitoring anomali radon dengan kejadian gempa di sekitar patahan Opak.
Analisis Kecepatan Gelombang Geser (Vs) Sebagai Upaya Mitigasi Bencana Gempabumi di Kulonprogo, DIY Susilanto, Pupung; Ngadmanto, Drajat; Sunardi, Bambang; Rohadi, Supriyanto
Jurnal Lingkungan dan Bencana Geologi Vol 10, No 2 (2019)
Publisher : Badan Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2207.597 KB) | DOI: 10.34126/jlbg.v10i2.215

Abstract

Posisi Kulonprogo yang berbatasan langsung dengan zona subduksi lempeng Eurasia - IndoAustralia dan keberadaan patahan-patahan lokal menyebabkan sering merasakan dampak guncangan gempabumi. Penelitian ini bertujuan untuk melakukan analisis kecepatan gelombang geser (Vs) sebagai salah satu upaya mitigasi bencana gempabumi di Kabupaten Kulonprogo. Nilai Vs dihasilkan dengan pengolahan 28 titik pengukuran Multichannel Analysis of Surface Wave (MASW) yang tersebar di daerah Kulonprogo. Pengolahan data dilakukan dengan membuat kurva yang menghubungkan antara kecepatan fase – frekuensi dan selanjutnya dilakukan picking pada fundamental mode serta dilakukan proses inversi untuk mendapatkan profil kecepatan gelombang geser 1 dimensi (Vs 1D). Hasil Vs 1D digunakan untuk menganalisis tingkat bahaya gempabumi. Analisis dilakukan pada nilai Vs secara spasial dan teknik penampang melintang berdasarkan nilai Vs 1D.  Hasil penelitian menunjukkan bahwa daerah Wates, Panjatan, Galur, dan Temon sisi Utara memiliki tingkat bahaya guncangan gempabumi yang relatif lebih besar daripada daerah lain di Kulonprogo. Hal ini dikarenakan pada daerah tersebut memiliki nilai Vs yang relatif lebih rendah (endapan jenis tanah lunak dan jenis tanah sedang yang cukup tebal) daripada daerah lain di Kab. Kulonprogo.
Anomalious Trends in Electromagnetic As Earthquake Precursors With Related Parameters at the Port Ratu Observatory Prayogo, Angga Setiyo; Sunardi, Bambang
Natural B Vol 3, No 1 (2015)
Publisher : Natural B

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1311.632 KB) | DOI: 10.21776/ub.natural-b.2015.003.01.5

Abstract

Research on electromagnetic anomalies as earthquake precursor was performed in many places and time. Pelabuhan Ratu Observatory. For validation, correlation between anomaly value and time length with earthquake that recorded at Pelabuhan Ratu Geophysical Observatory and have electromagnetic anomaly. Goals of this research were analyze correlation between anomaly pattern value and time length to earthquake magnitud and Rhypo. Data processed by polarization ratio and impedance of electromagnetic at ultra low frequency spectrum, the correlation method using regression and physical analysis between parameter. Data that used was electromagnetic and earthquake data that recorded and perceived at geophysical observatories of Pelabuhan Ratu. Results of electromagnetic anomaly value with magnetic polarization ratio was varies in 0.1 until 9.5, and also time length between 4 until 39 days before earthquake. Value of anomaly with impedance method was varies in 3.01 until 16.1, and also time length between 4 until 32 days before earthquake. In conclusion, known that trend correlation of the appearance of anomalous values and ranges of magnitude and distance Rhypo with magnetic polarization method showed a positive correlation, whereas a negative correlation with the impedance method. Negative correlation also obtained on relationship between Rhypoand magnitude of the span of time and the value of the polarization anomaly 
KORELASI POLARISASI MAGNET Z/H UNTUK IDENTIFIKASI PREKURSOR GEMPA DI SEKITAR PELABUHAN RATU Ahyar, Asep Saepul; Sunardi, Bambang
Spektra: Jurnal Fisika dan Aplikasinya Vol 2 No 3 (2017): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 2 Nomor 3, Desember 2017
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.023.03

Abstract

Abstrak Efek seismo-elektromagnetik yang berlangsung dalam rentang frekuensi luas yang mendahului gempa telah banyak dilaporkan dalam beberapa penelitian sebelumnya. Efek tersebut diharapkan dapat dimanfaatkan dalam mitigasi bencana gempa. Penelitian ini membahas penerapan metode korelasi polarisasi magnet komponen Z/H untuk mengidentifikasi prekursor gempa di sekitar Pelabuhan Ratu. Data yang dipergunakan adalah data magnet tiga komponen selama 31 hari sebelum kejadian gempa. Identifikasi  anomali  geomagnet dilakukan  dengan  menerapkan metode korelasi polarisasi magnet Z/H untuk  menghitung  rasio Simpangan koefisien  korelasi (Skk)  dengan  Deviasi  standar  simpangan  koefisien korelasi  (Dskk). Ambang batas anomali adalah -1. Nilai Skk/Dskk < -1 mengindikasikan adanya anomali geomagnet. Kemunculan badai magnetik yang mempengaruhi anomali geomagnet dievaluasi menggunakan Disturbance storm time index (indeks Dst). Hasil penerapan metode korelasi polarisasi magnet Z/H pada lima kasus gempa di sekitar Pelabuhan Ratu dari Januari – Maret 2017 dengan magnitudo M  > 4 dan memenuhi radius zona manisfestasi prekursor menunjukkan kemunculan anomali geomagnet yang dikategorikan sebagai prekursor gempa. Kemunculan anomali geomagnet berkisar antara 16 – 2 hari sebelum gempa terjadi. Kata-kata kunci: korelasi, geomagnet, prekursor gempa, Pelabuhan Ratu. Abstract Seismo-electromagnetic effects occurring in wide frequency range that preceded earthquake have been widely reported in several previous studies. The effect is expected to be utilized in earthquake disaster mitigation. This study discusses application of magnetic polarization correlation method of Z / H component to identify earthquake precursors around Pelabuhan Ratu. Data used are three components magnet data for 31 days before earthquake events. Identification of magnetic anomaly was done by applying the magnetic polarization Z / H method to calculate correlation coefficient ratio (Skk) with standard deviation of correlation coefficient deviation (Dskk). The anomaly threshold is -1. Less than -1 of Skk / Dskk values indicate geomagnetic anomaly. The emergence of geomagnetic storms that affect geomagnetic anomalies is evaluated using the Disturbance storm time index (Dst index). The result of application of Z / H magnet polarization correlation method in five earthquake cases around Pelabuhan Ratu from January to March 2017 with magnitude M > 4 and meeting precursor manifestation radius zone showed the occurrence of geomagnetic anomalies categorized as earthquake precursors. The appearance of geomagnetic anomalies ranged from 16 to 2 days before earthquakes occurred. Keywords: correlation, geomagnetic, earthquake precursor, Pelabuhan Ratu.
ACCELERATION RESPONSE SPECTRUM AND EFFECTIVE DURATION OF LEBAK EARTHQUAKE JANUARY 23, 2018 IN JAKARTA REGION Hiola, Muhammad Fikri Hayqal; Sunardi, Bambang
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 1 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 1, April 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.041.03

Abstract

Jakarta is the capital city of Indonesia with a very high population density low to the upper distribution of buildings which causes many areas of Jakarta to have a high vulnerability to natural disasters, one of which is an earthquake. One of the earthquakes felt this year was Lebak Banten Earthquake January 23, 2018, with a magnitude 6.1 at 13.34 local time. The depth of the earthquake was 61 Km at -7.09o S - 106.03o E, in the South Indian Ocean of Java Island. The epicenter was 43 km from Cilangkahan Village, Malingping Sub-district, Lebak District, Banten. We analyze the ground motion characteristics in the Jakarta area using 3 component acceleration data at Jakarta City Hall Office (JAKO) and Tanjung Priok Maritime Station (JATA) with dynamic statistical analysis method. The effective duration and earthquake response spectrum are determined using the acceleration data. In this study, the active period of the earthquake was calculated using the Trifunac and Brady method. The results of the analysis show that the most significant acceleration spectrum at JAKO station is found in component E of 0.07742 g in the period of 0.54 s while for the most significant acceleration spectrum JATA station found in component N of 0.04572 g in the period of 0.58 s. The effective duration obtained at JAKO stations was 56.76 s and JATA station 63.47 s. These results indicate that in the case of the Lebak earthquake, the further region from the epicenter of the earthquake has an effective duration which is relatively longer.
THE ANALYSIS OF SEISMOTECTONICS, PERIODICITY, AND CHANGING OF QUAKES LEVEL IN WEST NUSA TENGGARA AREA BASED ON 1973 – 2015 DATA Istiqomah, Melinda Utami; Sunardi, Bambang; Marzuki, Marzuki; Minardi, Suhayat
Indonesian Physical Review Vol 2, No 1 (2019)
Publisher : Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/ipr.v2i1.20

Abstract

This research was conducted as one of the earthquake disaster mitigation efforts in Nusa Tenggara Barat region, because this region is one of the regions in Indonesia which has a relatively high level of seismicity. The purpose of this research is to determine seismotectonic parameter, earthquake periodicity along with the average of seismicity rate changes in Nusa Tenggara Barat region. The data used in this research is the data sourced from the United States Geological Survey (USGS) and Badan Meteorologi Klimatologi dan Geofisika (BMKG) from Januari 1973 until February 2015 for Bali Strait region up to Banda Sea with coordinate boundaries of 1140–1300 East Longitude and 40-130 South Latitude. This research was conducted using the maximum likelihood method with second party of software Zmap ver 6.0 also software ArcGis ver 10 to map seismotectonic parameter, periodicity and the average velocity of seismicity rate changes. Variation b value range between 0.972–1.44, a low value of b are associated with high stress levels, and vice versa. The a value range between 6.67- 9.1, its show that the regions with high a value experience a relatively high earthquake incidence rate, and vice versa. The density of earthquake is about -2.63 to -2.01 logN/km2 or the occurrence of earthquakes in the area is very rare. Earthquake periodicity with magnitude (M) 6 SR is 5 to 18 year, M 6.5 SR is 16 to 67 year, M 7 SR is 54 to 304 year, and M 7.5 SR is 178 to 1.386 year. The average of seismicity rate changes on a case that occurred in Sumbawa in 1982 is more than 125%, meanwhile the earthquake that occurred in 2009 is more than 75%.Copyright © 2019IPR. All rights reserved.
Percepatan Tanah Sintetis Kota Yogyakarta Berdasarkan Deagregasi Bahaya Gempa Sunardi, Bambang
Jurnal Lingkungan dan Bencana Geologi Vol 6, No 3 (2015)
Publisher : Badan Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1872.917 KB) | DOI: 10.34126/jlbg.v6i3.85

Abstract

ABSTRAKYogyakarta merupakan kota dengan tingkat kerawanan gempa yang tinggi. Tingkat kerawanan gempa serta populasi penduduk yang tinggi menjadikan Yogyakarta sebagai kota dengan tingkat risiko yang tinggi terhadap gempa. Salah satu usaha untuk mengurangi risiko gempa adalah membuat peraturan tentang perencanaan bangunan tahan gempa. Salah satu komponen dalam peraturan kegempaan tersebut adalah tersedianya data percepatan tanah serta respons spektra. Oleh karena itu, penelitian tentang percepatan tanah yang sesuai untuk Kota Yogyakarta sangat penting untuk dilakukan. Tujuan penelitian ini adalah menentukan percepatan tanah sintetis dan respons spektra di permukaan yang sesuai untuk Kota Yogyakarta. Tahapan penelitian meliputi pengumpulan dan pengolahan data gempa, identifikasi, pemodelan dan karakterisasi sumber gempa, pengelolaan unsur ketidakpastian, analisis bahaya gempa probabilistik dan deagregasi, proses spectral matching, penentuan percepatan tanah sintetis dan respons spektra di permukaan untuk Kota Yogyakarta. Hasil penelitian merekomendasikan percepatan tanah sintetis dan respons spektra di permukaan Kota Yogyakarta mengacu pada data gempa Kern County, 1952 dan Imperial Valley, 1979 setelah diskalakan dan dilakukan proses spectral matching dipakai sebagai dasar desain percepatan tanah dan respons spektra akibat sumber gempa subduksi dan shallow crustal di kota ini.Kata kunci: deagregasi bahaya gempa, percepatan tanah sintetis, respons spektra, spectral matchingABSTRACTYogyakarta is a city with a high level of seismic hazard. The level of seismic hazard and high population makes Yogyakarta as a region with a high level of earthquake risk. One attempt to reduce the earthquake risk is to make regulation about planning of earthquake resistant building. One component in the earthquake regulation is the availability of ground acceleration and response spectra data. Therefore, research about suitable ground acceleration for Yogyakarta City is very important. The goals of this research is to determine suitable synthetic ground acceleration and surface response spectra for Yogyakarta City. Stages of the research involve the collection and processing of seismic data, identification, modeling and characterization of seismic sources, uncertainty management, probabilistic seismic hazard analysis and deaggregation, spectral matching process, synthetic ground acceleration and surface response spectra determination for Yogyakarta City. Results of the research recommend synthetic ground acceleration and response spectra at the surface for Yogyakarta City from Kern County, 1952 and Imperial Valley 1979 earthquake data after scaling and spectral matching process as ground acceleration and response spectra design due to subduction and shallow crustal earthquake source for this city.Keywords: seismic hazard deaggregation, synthetic ground acceleration, response spectra, spectral matching
PEMANTAUAN ANOMALI TOTAL ELECTRON CONTENT (TEC) BERKAITAN DENGAN KEJADIAN GEMPABUMI DI SEKITAR WILAYAH JAWA TAHUN 2015 Sunardi, Bambang; Sulastri, Sulastri
Spektra: Jurnal Fisika dan Aplikasinya Vol 1 No 2 (2016): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 1 Nomor 2, Desember 2016
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.0102.01

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Abstrak Penelitian tentang prekursor gempabumi yang terintegrasi melalui pengamatan parameter seismik, elektromagnetik, geokimia, geoatmosferik serta parameter ionosfer telah dilakukan untuk mendapatkan tanda-tanda awal sebelum gempabumi kuat di Indonesia. Salah satu yang sedang dikembangkan saat ini adalah pemantauan parameter Total Electron Content (TEC) dari data Global Ionosphere Map (GIM). Makalah ini menyajikan hasil-hasil pemantauan anomali TEC yang berkaitan dengan gempabumi magnitude M > 5 di sekitar wilayah Jawa selama tahun 2015. Pemantauan TEC dilakukan dengan menerapkan metode korelasi data TEC GIM hingga diperoleh perbandingan simpangan koefisien korelasi (skk) dengan deviasi standar simpangan koefisien korelasi (dskk) di dekat episenter gempabumi. Ambang batas anomali TEC merujuk pada penelitian sebelumnya yaitu -1. Apabila nilai skk/dskk < -1 maka diklasifikasikan sebagai anomali TEC. Data Disturbance storm time index (Dst indeks) dipergunakan untuk mengevaluasi adanya kaitan aktivitas badai geomagnetik dengan anomali TEC. Hasil pemantauan menunjukkan munculnya anomali TEC pada sebagian besar kasus gempabumi yang menjadi obyek penelitian. Dengan hanya mempertimbangkan pengamatan parameter TEC dan indeks Dst, anomali-anomali tersebut dapat diklasifikan sebagai prekursor gempabumi terdeteksi dan prekursor gempabumi / efek badai geomagnet terdeteksi. Kata kunci : TEC, GIM, indeks Dst, prekursor, gempabumi. Abstract Research on integrated earthquake precursors through observation of seismic, electromagnetic, geochemical, geoatmosferic and ionospheric parameters has been conducted to obtain early signs before great earthquakes in Indonesia. One method being developed is Total Electron Content (TEC) monitoring from the Global Ionosphere Map (GIM). This paper presented TEC anomalies monitoring associated with earthquakes having magnitude M > 5 around Java during 2015. TEC monitoring was done by applying TEC GIM data correlation method to get ratio of correlation coefficient deviation (skk) to standard deviation of correlation coefficient deviation (dskk) near earthquake epicenters. TEC anomaly threshold referred to the previous study is - 1. If skk/dskk values were < - 1, they can be classified as TEC anomalies. Disturbance storm time index (Dst index) data were used to evaluate links between geomagnetic storm activities and TEC anomalies. The monitoring results indicated appear of TEC anomalies in most earthquakes which became the objects of research. By only considering the observation of TEC parameters and Dst index, such anomalies can be classified as detected earthquake precursors and detected earthquake precursors / geomagnetic storm effects. Keywords : TEC, GIM, Dst index, precursor, earthquake.
Acceleration Response Spectra for M 7.4 Donggala Earthquake and Comparison with Design Spectra Sunardi, Bambang; Sulastri; Karnawati, Dwikorita; Haryoko, Urip; Rohadi, Supriyanto; Pramono, Sigit; Sungkowo, Ari
Journal of Sustainable Engineering: Proceedings Series Vol 1 No 1 (2019)
Publisher : Fakultas Teknik Universitas Sam Ratulangi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35793/joseps.v1i1.3

Abstract

A 7.4 magnitude earthquake have strucked Donggala on September 28th 2018, followed by tsunami and liquefaction which hit Palu, Central Sulawesi, a few minutes later. This event had resulted in damage to buildings, and caused more than 2,000 people were killed and injured. Indonesia already have a building code in form of SNI 1726:2002 which had been updated to SNI 1726:2012. This paper analyses the hazard level caused by the 2018 Donggala earthquake compared to the existing design spectra, as mentioned in SNI 1726:2002 and SNI 1726:2012. A simple analysis was carried out by comparing Donggala earthquake’s acceleration response spectra with the existing design spectra, at the MPSI accelerograph station. The site class at MPSI station is hard soil (SC). The seismic hazard in Palu and Donggala refers to SNI 1726:2002 is included in the earthquake area 4. The maximum earthquake response factor for earthquake area 4 is about 0.6 for hard soil type (SC). The MPSI station recorded peak ground acceleration of Donggala earthquake around 0.14 g. The acceleration response spectra recorded at the MPSI station showed a peak value of around 0.71 g for the N component. This value is actually still below the design spectra referring to SNI 1726:2012, which the peak value is 0.88 g for SC, but, it exceeded the design spectra of SNI 1726:2002.