T. A. P. Setiadi, A. R. Hakim, Rian Mahendra Taruna, Supriyanto Rohadi, Pupung Susilanto
Gempa bumi Banten berkekuatan 6,2 Mw pada tanggal 23 Januari 2018 menarik perhatian para ahli tentang pentingnya pengetahuan mengenai percepatan tanah maksimum dan spektra percepatan di permukaan untuk wilayah DKI Jakarta. Hasil PGA M , S MS , dan S M1 memegang peranan penting dalam peraturan desain seismik. wilayah DKI Jakarta. Hasil PGA M , S MS , dan S M1 memegang peranan penting dalam peraturan desain seismik. Tujuan dari penelitian ini adalah menentukan PGA M , S MS , dan S M1 untuk wilayah DKI Jakarta menggunakan Probabilistic Seismic Hazard Analysis (PSHA). Data yang digunakan adalah katalog gempa bumi BMKG, ISC, dan USGS dari tahun 1900 – 2018. Hasil analisis menunjukkan bahwa nilai PGA M untuk untuk probabilitas terlampaui 2% dalam 50 tahun di wilayah DKI Jakarta bervariasi dari 0,35 – 0,5 g. Sementara itu nilai S MS , dan S M1 untuk untuk probabilitas terlampaui 2% dalam 50 tahun di wilayah DKI Jakarta bervariasi dari 0,65 – 1g dan 0,8 – 1g. Nilai PGA M , S MS , dan S M1 relatif lebih tinggi di wilayah Kota Jakarta Selatan, Kota Jakarta Barat, dan Kota Jakarta Utara. The Mw 6.2 Banten earthquake on January 23, 2018, draws researchers’ attention to the importance of information about Peak Ground Acceleration and spectral acceleration on the surface for the DKI Jakarta area. The results of PGA M , S MS , and S M1 play an important role in the rules of seismic design. The purpose of this study was to determine PGA M , S MS , and S M1 for the DKI Jakarta area using Probabilistic Seismic Hazard Analysis (PSHA). The data used are the earthquake catalog BMKG, ISC, and USGS from 1900 - 2018. The analysis shows that the value of PGA M for DKI Jakarta varies from 0.35 – 0.5 g. Meanwhile, the value of S MS , and S M1 varies from 0.50 - 0.1 g and 0.8 - 1 g. The values of PGA M , S MS , and S M1 are relatively higher in the area of South Jakarta City, West Jakarta City, and North Jakarta City.
{"title":"PERCEPATAN TANAH MAKSIMUM DI PERMUKAAN PADA WILAYAH DKI JAKARTA MENGGUNAKAN METODE PROBABILISTIK","authors":"T. A. P. Setiadi, A. R. Hakim, Rian Mahendra Taruna, Supriyanto Rohadi, Pupung Susilanto","doi":"10.31172/jmg.v21i2.593","DOIUrl":"https://doi.org/10.31172/jmg.v21i2.593","url":null,"abstract":"Gempa bumi Banten berkekuatan 6,2 Mw pada tanggal 23 Januari 2018 menarik perhatian para ahli tentang pentingnya pengetahuan mengenai percepatan tanah maksimum dan spektra percepatan di permukaan untuk wilayah DKI Jakarta. Hasil PGA M , S MS , dan S M1 memegang peranan penting dalam peraturan desain seismik. wilayah DKI Jakarta. Hasil PGA M , S MS , dan S M1 memegang peranan penting dalam peraturan desain seismik. Tujuan dari penelitian ini adalah menentukan PGA M , S MS , dan S M1 untuk wilayah DKI Jakarta menggunakan Probabilistic Seismic Hazard Analysis (PSHA). Data yang digunakan adalah katalog gempa bumi BMKG, ISC, dan USGS dari tahun 1900 – 2018. Hasil analisis menunjukkan bahwa nilai PGA M untuk untuk probabilitas terlampaui 2% dalam 50 tahun di wilayah DKI Jakarta bervariasi dari 0,35 – 0,5 g. Sementara itu nilai S MS , dan S M1 untuk untuk probabilitas terlampaui 2% dalam 50 tahun di wilayah DKI Jakarta bervariasi dari 0,65 – 1g dan 0,8 – 1g. Nilai PGA M , S MS , dan S M1 relatif lebih tinggi di wilayah Kota Jakarta Selatan, Kota Jakarta Barat, dan Kota Jakarta Utara. The Mw 6.2 Banten earthquake on January 23, 2018, draws researchers’ attention to the importance of information about Peak Ground Acceleration and spectral acceleration on the surface for the DKI Jakarta area. The results of PGA M , S MS , and S M1 play an important role in the rules of seismic design. The purpose of this study was to determine PGA M , S MS , and S M1 for the DKI Jakarta area using Probabilistic Seismic Hazard Analysis (PSHA). The data used are the earthquake catalog BMKG, ISC, and USGS from 1900 - 2018. The analysis shows that the value of PGA M for DKI Jakarta varies from 0.35 – 0.5 g. Meanwhile, the value of S MS , and S M1 varies from 0.50 - 0.1 g and 0.8 - 1 g. The values of PGA M , S MS , and S M1 are relatively higher in the area of South Jakarta City, West Jakarta City, and North Jakarta City.","PeriodicalId":32347,"journal":{"name":"Jurnal Meteorologi dan Geofisika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88394072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bagus Endar B. Nurhandoko, Kaswandhi Triyoso, M. R. A. Hadi, Insanur Rizal, Djedi S. Widarto, Nurhasan Nurhasan
Kondisi geologi di Zona Kendeng ini cukup kompleks dengan dominasi lapisan yang berumur tua dan struktur sesar naik (thrust fault) yang intensif menyebabkan sulitnya memenuhi kebutuhan air bersih dari akuifer air tanah di daerah ini. Karakter akuifer di daerah ini berupa batuan napal karbonat formasi Kerek berumur Miosen.Analisis akuifer pada penelitian ini meliputi uji resistivity rock physics, pengukuran sudut kontak, dan pengukuran resistivitas tomografi di lapangan.Pengukuran resistivity rock physics menghasilkan nilai resistivitas batuan pada keadaan kering dan pada keadaan tersaturasi air tanah. Nilai resistivitas ini menjadi referensi untuk karakterisasi citra tomografi resistivitas. Sedangkan nilai sudut kontak menunjukkan apakah air akan merambat ke atas ataukan tertekan lebih dalam. Hasil pengukuran sudut kontak yang selalu bersudut kecil memperlihatkan bahwa sistem kapilaritas di akuifer napal karbonat formasi Kerek ini mendukung untuk menjadi akuifer yang baik. Air cenderung terangkat keatas. Karakterisasi terhadap akuifer air tanah dengan metode tomografi resisitivitas berhasil mencitrakan sejumlah lokasi akuifer air tanah yang potensial meskipun dengan struktur yang relatif didominasi lapisan tegak. Permasalahannya karena akuifer napal karbonat ini dikelilingi oleh lapisan clay berumur Miosen yang impermeabel, maka recharge akuifer di daerah ini justru sangat mengandalkan akuifer dengan struktur-struktur berarah tegak.
{"title":"Karakterisasi Akuifer Berumur Miosen di Daerah Geologi Kompleks Thrust Fault Zona Kendeng dengan Rock Physics dan Tomografi Resistivitas","authors":"Bagus Endar B. Nurhandoko, Kaswandhi Triyoso, M. R. A. Hadi, Insanur Rizal, Djedi S. Widarto, Nurhasan Nurhasan","doi":"10.36435/JGF.V18I2.433","DOIUrl":"https://doi.org/10.36435/JGF.V18I2.433","url":null,"abstract":"Kondisi geologi di Zona Kendeng ini cukup kompleks dengan dominasi lapisan yang berumur tua dan struktur sesar naik (thrust fault) yang intensif menyebabkan sulitnya memenuhi kebutuhan air bersih dari akuifer air tanah di daerah ini. Karakter akuifer di daerah ini berupa batuan napal karbonat formasi Kerek berumur Miosen.Analisis akuifer pada penelitian ini meliputi uji resistivity rock physics, pengukuran sudut kontak, dan pengukuran resistivitas tomografi di lapangan.Pengukuran resistivity rock physics menghasilkan nilai resistivitas batuan pada keadaan kering dan pada keadaan tersaturasi air tanah. Nilai resistivitas ini menjadi referensi untuk karakterisasi citra tomografi resistivitas. Sedangkan nilai sudut kontak menunjukkan apakah air akan merambat ke atas ataukan tertekan lebih dalam. Hasil pengukuran sudut kontak yang selalu bersudut kecil memperlihatkan bahwa sistem kapilaritas di akuifer napal karbonat formasi Kerek ini mendukung untuk menjadi akuifer yang baik. Air cenderung terangkat keatas. Karakterisasi terhadap akuifer air tanah dengan metode tomografi resisitivitas berhasil mencitrakan sejumlah lokasi akuifer air tanah yang potensial meskipun dengan struktur yang relatif didominasi lapisan tegak. Permasalahannya karena akuifer napal karbonat ini dikelilingi oleh lapisan clay berumur Miosen yang impermeabel, maka recharge akuifer di daerah ini justru sangat mengandalkan akuifer dengan struktur-struktur berarah tegak. \u0000 ","PeriodicalId":32347,"journal":{"name":"Jurnal Meteorologi dan Geofisika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81480878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Edwin Brilliant, Sanggeni Gali Wardhana, A. Bilqis, Alda Ressa Nurdianingsih, Rafif Rajendra Widya Daniswara, W. Pranowo
Multi-Point Geostatistics (MPS) is a type of geostatistical method used to estimate the value of an unsampled location by utilizing several data points around it simultaneously. The MPS method estimates it by defining a model based on initial data in the form of a training image, which is a collection of data in the form of a geological conceptual model in the research area with the integration of geological and geophysical knowledge. The MPS method is currently starting to develop because it differs from conventional covariance-based geostatistical methods such as simple kriging and ordinary kriging, which only use a variogram based on the relationship between two points rapidly. In this study, we evaluated the use of the MPS method by using a direct sampling algorithm with Python that will directly sample the training image and then retrieve the data based on the sample data. A braided channel training image is used as the initial model to estimate the distribution of reservoir properties in lithology with sand and shale types. This study shows that MPS could reconstruct geological features better than kriging.
{"title":"A Python Based Multi-Point Geostatistics by using Direct Sampling Algorithm","authors":"Edwin Brilliant, Sanggeni Gali Wardhana, A. Bilqis, Alda Ressa Nurdianingsih, Rafif Rajendra Widya Daniswara, W. Pranowo","doi":"10.36435/JGF.V18I2.446","DOIUrl":"https://doi.org/10.36435/JGF.V18I2.446","url":null,"abstract":"Multi-Point Geostatistics (MPS) is a type of geostatistical method used to estimate the value of an unsampled location by utilizing several data points around it simultaneously. The MPS method estimates it by defining a model based on initial data in the form of a training image, which is a collection of data in the form of a geological conceptual model in the research area with the integration of geological and geophysical knowledge. The MPS method is currently starting to develop because it differs from conventional covariance-based geostatistical methods such as simple kriging and ordinary kriging, which only use a variogram based on the relationship between two points rapidly. In this study, we evaluated the use of the MPS method by using a direct sampling algorithm with Python that will directly sample the training image and then retrieve the data based on the sample data. A braided channel training image is used as the initial model to estimate the distribution of reservoir properties in lithology with sand and shale types. This study shows that MPS could reconstruct geological features better than kriging.","PeriodicalId":32347,"journal":{"name":"Jurnal Meteorologi dan Geofisika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83266538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Ulfiana, W. Wandono, D. Sianipar, N. Heryandoko
Mt. Jailolo is a B type volcano that has never erupted after 1600. Seismic activities around Mt. Jailolo have never been recorded until the swarm in November 2015. Several studies have been done to determine thecause of the swarm, but it is not certain whether the cause of the swarm is tectonic or volcanic activities. The study of attenuation characteristics has never been carried out in the area around Mt. Jailolo. Attenuation characteristics are important to provide the medium information which seismic waves pass through and it can also be applied to the volcanic areas as preliminary disaster mitigation. The main objective of this study is to analyze attenuation characteristics often expressed by Quality factor (Q-factor) of P and S seismic wave (Qα and Qβ), which are inversely proportional to attenuation factor (1/Q). Calculations of Qα and Qβ are obtained using coda normalization method. The study area location is around Mt. Jailolo at 127.3◦ - 127.6◦E and 0.9◦ - 1.2◦ N. Data have been collected with 12 Short Period temporary 7G sensors network belongs to GFZ and BMKG. This study uses 147 swarm events from the sensors with a threshold magnitude of Mw< 5.0, during April 2017. The study obtains Qα(f) = 9.61814f 1.12981 and Qβ(f) = 19.10690f 1.22843. The current analysis concludes that the attenuation beneath Mt. Jailolo corresponds to the volcanic swarms which may have been triggered by its deeper layer’s magmatic activity.
{"title":"Study of P and S Wave Quality Factor (Qα and Qβ) Around Mt. Jailolo","authors":"E. Ulfiana, W. Wandono, D. Sianipar, N. Heryandoko","doi":"10.36435/JGF.V18I2.437","DOIUrl":"https://doi.org/10.36435/JGF.V18I2.437","url":null,"abstract":"Mt. Jailolo is a B type volcano that has never erupted after 1600. Seismic activities around Mt. Jailolo have never been recorded until the swarm in November 2015. Several studies have been done to determine thecause of the swarm, but it is not certain whether the cause of the swarm is tectonic or volcanic activities. The study of attenuation characteristics has never been carried out in the area around Mt. Jailolo. Attenuation characteristics are important to provide the medium information which seismic waves pass through and it can also be applied to the volcanic areas as preliminary disaster mitigation. The main objective of this study is to analyze attenuation characteristics often expressed by Quality factor (Q-factor) of P and S seismic wave (Qα and Qβ), which are inversely proportional to attenuation factor (1/Q). Calculations of Qα and Qβ are obtained using coda normalization method. The study area location is around Mt. Jailolo at 127.3◦ - 127.6◦E and 0.9◦ - 1.2◦ N. Data have been collected with 12 Short Period temporary 7G sensors network belongs to GFZ and BMKG. This study uses 147 swarm events from the sensors with a threshold magnitude of Mw< 5.0, during April 2017. The study obtains Qα(f) = 9.61814f 1.12981 and Qβ(f) = 19.10690f 1.22843. The current analysis concludes that the attenuation beneath Mt. Jailolo corresponds to the volcanic swarms which may have been triggered by its deeper layer’s magmatic activity.","PeriodicalId":32347,"journal":{"name":"Jurnal Meteorologi dan Geofisika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90174522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One year observation of Mesoscale Convective Complexes (MCCs) over the Indonesian Maritime Continent (BMI) and its impact to the rainfall are analyzed. This study is focused on the area of BMI where the MCCs formed and then the criteria are identified based on the size, initiate, duration, shape, and the eccentricity. In term of rainfall, this research also confirm that MCCs will have an impact to the rainfall distribution around the MCCs area. The first MCCs was developed on March, 15 and covered 348,410 km2 of the area. The most significant of MCCs was contributed to a 108 mm of rainfall occurs on December, 28 with 11 hours of duration and covered 771,448 km2 of area. The lag-time between rainfall and the mature stage of MCCs could be 1-3 hours. Furthermore, all initiations of the MCC occurred at night with a duration of between 8-15 hours. Throughout the MCCs event, top cloud of temperature derived by the Multi-functional Transport Satellite (MTSAT)-IR imagery could reached the temperature < -85 °C. Keyword s : MCCs, BMI, rainfall, cloud
{"title":"IDENTIFIKASI MESOSCALE CONVECTIVE COMPLEX (MCC) DAN DAMPAKNYA TERHADAP CURAH HUJAN DI BENUA MARITIM INDONESIA (BMI) SEPANJANG TAHUN 2018","authors":"Deni Septiadi, Yudhi Nugraha Septiadi","doi":"10.31172/jmg.v20i2.645","DOIUrl":"https://doi.org/10.31172/jmg.v20i2.645","url":null,"abstract":"One year observation of Mesoscale Convective Complexes (MCCs) over the Indonesian Maritime Continent (BMI) and its impact to the rainfall are analyzed. This study is focused on the area of BMI where the MCCs formed and then the criteria are identified based on the size, initiate, duration, shape, and the eccentricity. In term of rainfall, this research also confirm that MCCs will have an impact to the rainfall distribution around the MCCs area. The first MCCs was developed on March, 15 and covered 348,410 km2 of the area. The most significant of MCCs was contributed to a 108 mm of rainfall occurs on December, 28 with 11 hours of duration and covered 771,448 km2 of area. The lag-time between rainfall and the mature stage of MCCs could be 1-3 hours. Furthermore, all initiations of the MCC occurred at night with a duration of between 8-15 hours. Throughout the MCCs event, top cloud of temperature derived by the Multi-functional Transport Satellite (MTSAT)-IR imagery could reached the temperature < -85 °C. Keyword s : MCCs, BMI, rainfall, cloud","PeriodicalId":32347,"journal":{"name":"Jurnal Meteorologi dan Geofisika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79359851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
“MRD” field is an oil and gas field which located in Rembang Zone. One of the hydrocarbon zones in this fieldlies in Ngimbang Formation. Reservoir in this field has a lifespan of Middle Eocene to Early Oligocene. Reservoir of this formation is carbonate rocks and dominated by calcite and dolomite minerals. One of the uniqueness of this kind of reservoir is the pore shape which quite complex. In this study, reservoir characterization which performed on this field is based on elastic properties modelling. Elastic Properties modelling which was conducted in this field can provide an output of the pore shape, aspect ratio, and the fraction of each respective poresforms that exist in this field’s reservoir zone. Therefore the primary data such as petrophysical data, XRD (X-Ray Diffraction), and the data of other reservoir parameters are needed for more accurate resultsobtained with real conditions. The result of this modelling shows that the shape of the pores in the reservoir zone at any depth can be predicted. Distribution of pore shapes that exist in the two wells can be used as a reference for prospective determination of hydrocarbon zones in “MRD” field.
{"title":"Elastic Properties Modeling for Identification of Prospective Reservoir Zones in the Carbonate Reservoir, MRD Field in the North East Java Basin","authors":"M. Mordekhai, S. Winardhi","doi":"10.36435/jgf.v17i1.34","DOIUrl":"https://doi.org/10.36435/jgf.v17i1.34","url":null,"abstract":"“MRD” field is an oil and gas field which located in Rembang Zone. One of the hydrocarbon zones in this fieldlies in Ngimbang Formation. Reservoir in this field has a lifespan of Middle Eocene to Early Oligocene. Reservoir of this formation is carbonate rocks and dominated by calcite and dolomite minerals. One of the uniqueness of this kind of reservoir is the pore shape which quite complex. In this study, reservoir characterization which performed on this field is based on elastic properties modelling. Elastic Properties modelling which was conducted in this field can provide an output of the pore shape, aspect ratio, and the fraction of each respective poresforms that exist in this field’s reservoir zone. Therefore the primary data such as petrophysical data, XRD (X-Ray Diffraction), and the data of other reservoir parameters are needed for more accurate resultsobtained with real conditions. The result of this modelling shows that the shape of the pores in the reservoir zone at any depth can be predicted. Distribution of pore shapes that exist in the two wells can be used as a reference for prospective determination of hydrocarbon zones in “MRD” field. \u0000 ","PeriodicalId":32347,"journal":{"name":"Jurnal Meteorologi dan Geofisika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75061617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Priadi, A. Wijaya, Maria Annaluna Pasaribu, Riska Yulinda
September 28th, 2018, Donggala-Palu earthquake M 7.5 occurred at depth of 12 km and generated tsunami to be released off the coast in Palu Bay. The tsunami that occurred in Palu was very interesting because the results of the earthquake source mechanism Palu had a type of strike-slip fault that should not have generated a tsunami. This study purpose to estimate the characteristics of the Donggala-Palu tsunami based on rupture duration ( and orientation fault activated using the HC-plot method. The data used in this study are data waveforms from 17 seismic stations and CMT Global catalog data with the area of research 0.87 0 N-1.78 0S dan 118.640E- 120.95 0E. The waveform data used is a phase P-PP vertical component signal with a Bandpass-filter 1-5 Hz for determination . The fastest rupture duration from the earthquake source is obtained from the calculation of each station. Delay time measurement after P wave for 90% (T0.9), 80% (T0.8), 50% (T0.5), dan 20% (T0.2) from its peak value. Then the HC-plot method is used to estimate the orientation of generator fault Palu earthquake and the direction of rupture from the focal mechanism. From the results of processing obtained 2 pairs of seismic stations with almost the same distance but with different azimuths. The fastest rupture duration is at BBSI station with value of 82.014 s and distance from station to epicenter . So that the rupture direction is in the azimuth from the north. The result of fault orientation was obtained hypocenter distance to the centroid for nodal plane 1 is 6.32 km and nodal plane 2 is 30.17 km with distance centroid to hypocenter is 31.22 km. So in Palu earthquake, the tsunami generator fault was in nodal plane 1 with direction north-south. Criteria obtained indicate that the Palu earthquake M 7.5 has potential for a tsunami because of its value has meet ≥ 65 s, but from the result of the focal mechanism direction field not passing through the Palu bay is thought to be another parameter that generates a tsunami and Palu koro fault line uncharted.
{"title":"Analysis of the Donggala-Palu Tsunami Characteristics based on Rupture Duration (Tdur) and Active Fault Orientation using the HC-plot Method","authors":"R. Priadi, A. Wijaya, Maria Annaluna Pasaribu, Riska Yulinda","doi":"10.36435/jgf.v17i1.392","DOIUrl":"https://doi.org/10.36435/jgf.v17i1.392","url":null,"abstract":"September 28th, 2018, Donggala-Palu earthquake M 7.5 occurred at depth of 12 km and generated tsunami to be released off the coast in Palu Bay. The tsunami that occurred in Palu was very interesting because the results of the earthquake source mechanism Palu had a type of strike-slip fault that should not have generated a tsunami. This study purpose to estimate the characteristics of the Donggala-Palu tsunami based on rupture duration ( and orientation fault activated using the HC-plot method. The data used in this study are data waveforms from 17 seismic stations and CMT Global catalog data with the area of research 0.87 0 N-1.78 0S dan 118.640E- 120.95 0E. The waveform data used is a phase P-PP vertical component signal with a Bandpass-filter 1-5 Hz for determination . The fastest rupture duration from the earthquake source is obtained from the calculation of each station. Delay time measurement after P wave for 90% (T0.9), 80% (T0.8), 50% (T0.5), dan 20% (T0.2) from its peak value. Then the HC-plot method is used to estimate the orientation of generator fault Palu earthquake and the direction of rupture from the focal mechanism. From the results of processing obtained 2 pairs of seismic stations with almost the same distance but with different azimuths. The fastest rupture duration is at BBSI station with value of 82.014 s and distance from station to epicenter . So that the rupture direction is in the azimuth from the north. The result of fault orientation was obtained hypocenter distance to the centroid for nodal plane 1 is 6.32 km and nodal plane 2 is 30.17 km with distance centroid to hypocenter is 31.22 km. So in Palu earthquake, the tsunami generator fault was in nodal plane 1 with direction north-south. Criteria obtained indicate that the Palu earthquake M 7.5 has potential for a tsunami because of its value has meet ≥ 65 s, but from the result of the focal mechanism direction field not passing through the Palu bay is thought to be another parameter that generates a tsunami and Palu koro fault line uncharted.","PeriodicalId":32347,"journal":{"name":"Jurnal Meteorologi dan Geofisika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82151134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sulawesi is an area that has a high potential for tsunamis, especially in the North Sulawesi region due to the presence of a Pundungan Mayu subduction resulting from a double collision between the Maluku Sea plate and Halmahera and Sangihe arcs. Analysis of the duration rupture and estimated Mwp has been carried out using the P-wave phase in the North Sulawesi region as one of the tsunami early warning parameters. The data used were teleseismic body wave (300-900) from three earthquake-generating earthquakes with magnitudes above 7 (Sulawesi earthquake November 16, 2008, Celebes earthquake February 11, 2009, Molucca earthquake November 15, 2014) taken from the IRIS waveform catalog with 90 stations BHZ component registrar. The wave used is the P-PP wave phase (20% -90%) with a high frequency bandpass (1-2 Hz) butterworth filter. The results of the duration of the rupture obtained for the Sulawesi earthquake, Celebes earthquake, Molucca earthquake respectively 53.72 s, 52.98 s, 52.50 s. Whereas for Mwp, it has conformity with Mw from the IRIS catalog. So it can be concluded that the tsunami-generating earthquake in Sulawesi has a duration of rupture greater than 50 s which can be categorized as tsunamigenic earthquake (> 50 s) and the use of Mwp can be applied. Keywords : rupture duration, tsunami, Northern Sulawesi, Mwp
{"title":"Estimation of Rupture Duration and Mwp Values to Identify Tsunami Generating Earthquakes in Northern Sulawesi","authors":"M. F. H. Hiola, A. Nasrurroh","doi":"10.36435/jgf.v17i1.382","DOIUrl":"https://doi.org/10.36435/jgf.v17i1.382","url":null,"abstract":"Sulawesi is an area that has a high potential for tsunamis, especially in the North Sulawesi region due to the presence of a Pundungan Mayu subduction resulting from a double collision between the Maluku Sea plate and Halmahera and Sangihe arcs. Analysis of the duration rupture and estimated Mwp has been carried out using the P-wave phase in the North Sulawesi region as one of the tsunami early warning parameters. The data used were teleseismic body wave (300-900) from three earthquake-generating earthquakes with magnitudes above 7 (Sulawesi earthquake November 16, 2008, Celebes earthquake February 11, 2009, Molucca earthquake November 15, 2014) taken from the IRIS waveform catalog with 90 stations BHZ component registrar. The wave used is the P-PP wave phase (20% -90%) with a high frequency bandpass (1-2 Hz) butterworth filter. The results of the duration of the rupture obtained for the Sulawesi earthquake, Celebes earthquake, Molucca earthquake respectively 53.72 s, 52.98 s, 52.50 s. Whereas for Mwp, it has conformity with Mw from the IRIS catalog. So it can be concluded that the tsunami-generating earthquake in Sulawesi has a duration of rupture greater than 50 s which can be categorized as tsunamigenic earthquake (> 50 s) and the use of Mwp can be applied. \u0000Keywords : rupture duration, tsunami, Northern Sulawesi, Mwp","PeriodicalId":32347,"journal":{"name":"Jurnal Meteorologi dan Geofisika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86841329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Ardianto, Y. Husni, A. Nugraha, M. Muzli, Z. Zulfakriza, H. Afif, D. Sahara, S. Widiyantoro, A. Priyono, N. Puspito, P. Supendi, A. Riyanto, S. Wei, B. S. Prabowo
The ability to identify earthquake events that are consistent, efficient and accurate is increasingly needed along with the increase in the amount of data analyzed. In this paper a filter picker algorithm is implemented to identify aftershock events and determination of arrival time automatically, especially for the P wave phase. Here modifications are made in determining the uncertainty of arrival time and there are additional criteria in determining the time of arrival used. The additional criteria are that in a certain time span, there are at least 5 stations determined by the time the filter picker arrives. This is done to minimize identification errors due to local noise and other practical reasons, namely the minimum number of stations to determine the location and other seismological analysis. To test the filter picker algorithm, aftershock data from the Lombok earthquake occurred on July 29 (M 6.4), August 5 (M 7), and August 19 (M 6.3 and M 6.9) 2018. The aftershock data were used for 30 days, from August 4, 2018 to September 4, 2018 using local seismic station in Lombok Island. The results of the filter picker algorithm were evaluated by comparing the number of earthquake events detected and the accuracy of determining the P wave arrival time automatically to the results of manually arriving time. In addition, a comparison of the results obtained from a broadband type seismometer with a short period is used to find out how much influence the type of tool has on its performance results. The results of the comparison with the manual arrival time show that more than 85 percent of the results of the automatic arrival time have a difference below 0.2 seconds. Therefore, it can be said that the filter picker algorithm is quite effective for identifying events and determining the arrival time of P waves. In this paper it is also shown that this algorithm can be used for broad band and short period seismometer sensor, even without the prior correction of instruments.
{"title":"Implementation of Filter Picker Algorithm For Aftershock Identification of Lombok Earthquake 2018","authors":"A. Ardianto, Y. Husni, A. Nugraha, M. Muzli, Z. Zulfakriza, H. Afif, D. Sahara, S. Widiyantoro, A. Priyono, N. Puspito, P. Supendi, A. Riyanto, S. Wei, B. S. Prabowo","doi":"10.36435/jgf.v17i1.397","DOIUrl":"https://doi.org/10.36435/jgf.v17i1.397","url":null,"abstract":"The ability to identify earthquake events that are consistent, efficient and accurate is increasingly needed along with the increase in the amount of data analyzed. In this paper a filter picker algorithm is implemented to identify aftershock events and determination of arrival time automatically, especially for the P wave phase. Here modifications are made in determining the uncertainty of arrival time and there are additional criteria in determining the time of arrival used. The additional criteria are that in a certain time span, there are at least 5 stations determined by the time the filter picker arrives. This is done to minimize identification errors due to local noise and other practical reasons, namely the minimum number of stations to determine the location and other seismological analysis. To test the filter picker algorithm, aftershock data from the Lombok earthquake occurred on July 29 (M 6.4), August 5 (M 7), and August 19 (M 6.3 and M 6.9) 2018. The aftershock data were used for 30 days, from August 4, 2018 to September 4, 2018 using local seismic station in Lombok Island. The results of the filter picker algorithm were evaluated by comparing the number of earthquake events detected and the accuracy of determining the P wave arrival time automatically to the results of manually arriving time. In addition, a comparison of the results obtained from a broadband type seismometer with a short period is used to find out how much influence the type of tool has on its performance results. The results of the comparison with the manual arrival time show that more than 85 percent of the results of the automatic arrival time have a difference below 0.2 seconds. Therefore, it can be said that the filter picker algorithm is quite effective for identifying events and determining the arrival time of P waves. In this paper it is also shown that this algorithm can be used for broad band and short period seismometer sensor, even without the prior correction of instruments.","PeriodicalId":32347,"journal":{"name":"Jurnal Meteorologi dan Geofisika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91203517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. K. Suhardja, Yosua Hotmaruli Lumban Gaol, A. Abdullah, A. Nugraha, Z. Zulfakriza
We performed 3-D seismic tomography using teleseismic arrival time at Southwest Mexico. The Mexican subduction zone results from successive fragmentation events that affected the ancient Farallon plate as various segments of the East Pacific rise approached the paleo-trench off western North America. The complexity in this region is related to two subducting oceanic plates, the Rivera and Cocos plates, that have different ages, compositions, convergence velocities and subduction dip angles. In this study, we compared the 3-D raytracing tomography model with finite frequency tomography model. Final models show the differences in amplitude and pattern between the raytracing and finite frequency. 3D raytracing models produced sharper images of fast velocity structures in the mantle. The deeper slabs are more coherent and show less broadening with depth than using 1D finite frequency kernels. However, although the finite frequency and 3-D ray tracing models show some differences in amplitude and pattern, the overall agreement of the models supports the interpretation of Yang et al. (2009) that slab rollback is occurring in South Western Mexico. One possible different interpretation between the raytracing and finite frequency theory results concerns the deep structure of the Rivera slab. The finite frequency models show that the Rivera slab is clearly observable at a depth of about 300km but fades away at greater depths. However, the 3-D ray tracing model shows a clear fast velocity band down to a depth of 400 km and thus our model does not support a slab tear of the Rivera plate above 400 km depth
{"title":"Comparison of 3-D Raytracing and Finite Frequency Tomography","authors":"S. K. Suhardja, Yosua Hotmaruli Lumban Gaol, A. Abdullah, A. Nugraha, Z. Zulfakriza","doi":"10.36435/jgf.v17i1.393","DOIUrl":"https://doi.org/10.36435/jgf.v17i1.393","url":null,"abstract":"We performed 3-D seismic tomography using teleseismic arrival time at Southwest Mexico. The Mexican subduction zone results from successive fragmentation events that affected the ancient Farallon plate as various segments of the East Pacific rise approached the paleo-trench off western North America. The complexity in this region is related to two subducting oceanic plates, the Rivera and Cocos plates, that have different ages, compositions, convergence velocities and subduction dip angles. In this study, we compared the 3-D raytracing tomography model with finite frequency tomography model. Final models show the differences in amplitude and pattern between the raytracing and finite frequency. 3D raytracing models produced sharper images of fast velocity structures in the mantle. The deeper slabs are more coherent and show less broadening with depth than using 1D finite frequency kernels. However, although the finite frequency and 3-D ray tracing models show some differences in amplitude and pattern, the overall agreement of the models supports the interpretation of Yang et al. (2009) that slab rollback is occurring in South Western Mexico. One possible different interpretation between the raytracing and finite frequency theory results concerns the deep structure of the Rivera slab. The finite frequency models show that the Rivera slab is clearly observable at a depth of about 300km but fades away at greater depths. However, the 3-D ray tracing model shows a clear fast velocity band down to a depth of 400 km and thus our model does not support a slab tear of the Rivera plate above 400 km depth","PeriodicalId":32347,"journal":{"name":"Jurnal Meteorologi dan Geofisika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78947323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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