This paper highlights the crucial role of Indonesia’s GNSS receiver network in advancing Equatorial Plasma Bubble(EPB)studies in Southeast and East Asia,as ionospheric irregularities within EPB can disrupt GNSS signa...This paper highlights the crucial role of Indonesia’s GNSS receiver network in advancing Equatorial Plasma Bubble(EPB)studies in Southeast and East Asia,as ionospheric irregularities within EPB can disrupt GNSS signals and degrade positioning accuracy.Managed by the Indonesian Geospatial Information Agency(BIG),the Indonesia Continuously Operating Reference Station(Ina-CORS)network comprises over 300 GNSS receivers spanning equatorial to southern low-latitude regions.Ina-CORS is uniquely situated to monitor EPB generation,zonal drift,and dissipation across Southeast Asia.We provide a practical tool for EPB research,by sharing two-dimensional rate of Total Electron Content(TEC)change index(ROTI)derived from this network.We generate ROTI maps with a 10-minute resolution,and samples from May 2024 are publicly available for further scientific research.Two preliminary findings from the ROTI maps of Ina-CORS are noteworthy.First,the Ina-CORS ROTI maps reveal that the irregularities within a broader EPB structure persist longer,increasing the potential for these irregularities to migrate farther eastward.Second,we demonstrate that combined ROTI maps from Ina-CORS and GNSS receivers in East Asia and Australia can be used to monitor the development of ionospheric irregularities in Southeast and East Asia.We have demonstrated the combined ROTI maps to capture the development of ionospheric irregularities in the Southeast/East Asian sector during the G5 Geomagnetic Storm on May 11,2024.We observed simultaneous ionospheric irregularities in Japan and Australia,respectively propagating northwestward and southwestward,before midnight,whereas Southeast Asia’s equatorial and low-latitude regions exhibited irregularities post-midnight.By sharing ROTI maps from Indonesia and integrating them with regional GNSS networks,researchers can conduct comprehensive EPB studies,enhancing the understanding of EPB behavior across Southeast and East Asia and contributing significantly to ionospheric research.展开更多
Equatorial Plasma Bubbles(EPBs)are ionospheric irregularities that take place near the magnetic equator.EPBs most commonly occur after sunset during the equinox months,although they can also be observed during other s...Equatorial Plasma Bubbles(EPBs)are ionospheric irregularities that take place near the magnetic equator.EPBs most commonly occur after sunset during the equinox months,although they can also be observed during other seasons.The phenomenon significantly disrupts radio wave signals essential to communication and navigation systems.The national network of Global Navigation Satellite System(GNSS)receivers in Indonesia(>30°longitudinal range)provides an opportunity for detailed EPB studies.To explore this,we conducted preliminary 3D tomography of total electron content(TEC)data captured by GNSS receivers following a geomagnetic storm on December 3,2023,when at least four EPB clusters occurred in the Southeast Asian sector.TEC and extracted TEC depletion with a 120-minute running average were then used as inputs for a 3D tomography program.Their 2D spatial distribution consistently captured the four EPB clusters over time.These tomography results were validated through a classical checkerboard test and comparisons with other ionospheric data sources,such as the Global Ionospheric Map(GIM)and International Reference Ionosphere(IRI)profile.Validation of the results demonstrates the capability of the Indonesian GNSS network to measure peak ionospheric density.These findings highlight the potential for future three-dimensional research of plasma bubbles in low-latitude regions using existing GNSS networks,with extensive longitudinal coverage.展开更多
Precise coseismic displacements in earthquake/tsunamic early warning are necessary to characterize earthquakes in real time in order to enable decision-makers to issue alerts for public safety.Real-time global navigat...Precise coseismic displacements in earthquake/tsunamic early warning are necessary to characterize earthquakes in real time in order to enable decision-makers to issue alerts for public safety.Real-time global navigation satellite systems(GNSSs)have been a valuable tool in monitoring seismic motions,allowing permanent displacement computation to be unambiguously achieved.As a valuable tool presented to the seismic commu nity,the GSeisRT software developed by Wuhan University(China)can realize multi-GNSS precise point positioning with ambiguity resolution(PPP-AR)and achieve centimeterlevel to sub-centimeter-level precision in real time.While the stable maintenance of a global precise point positioning(PPP)service is challenging,this software is capable of estimating satellite clocks and phase biases in real time using a regional GNSS network.This capability makes GSeisRT especially suitable for proprietary GNSS networks and,more importantly,the highest possible positio ning precision and reliability can be obtained.According to real-time results from the Network of the Americas,the mean root mean square(RMS)errors of kinematic PPP-AR over a 24 h span are as low as 1.2,1.3,and 3.0 cm in the east,north,and up components,respectively.Within the few minutes that span a typical seismic event,a horizontal displacement precision of 4 mm can be achieved.The positioning precision of the GSeisRT regional PPP/PPP-AR is 30%-40%higher than that of the global PPP/PPP-AR.Since 2019,GSeisRT has successfully recorded the static,dynamic,and peak ground displacements for the 2020Oaxaca,Mexico moment magnitude(Mw)7.4 event;the 2020 Lone Pine,California Mw 5.8 event;and the 2021 Qinghai,China Mw 7.3 event in real time.The resulting immediate magnitude estimates have an error of around 0.1 only.The GSeisRT software is open to the scientific community and has been applied by the China Earthquake Ne tworks Center,the EarthScope Consortium of the United States,the National Seismological Center of Chile,Institute of Geological and Nuclear Sciences Limited(GNS Science Te PūAo)of New Zealand,and the Geospatial Information Agency of Indonesia.展开更多
The Mentawai Forearc Sliver(MFS)is characterized by oblique deformation formed as slip partitioned between normal and parallel trench plate convergence.The surge of great earthquakes from 2004 to2012 along the adjacen...The Mentawai Forearc Sliver(MFS)is characterized by oblique deformation formed as slip partitioned between normal and parallel trench plate convergence.The surge of great earthquakes from 2004 to2012 along the adjacent Sunda trench left a large unbroken segment known as the Mentawai Seismic Gap.Here,we adopted continuous Global Navigation Satellite System(GNSS)observation data to identify the present regional crustal deformation using geodetic strain rates.The principal strain rate,dilatation rate,and maximum shear strain rate are about 0.13 microstrain/yr,0.2 microstrain/yr,and 0.1 microstrain/yr,respectively,with the range of its uncertainties between 0.01 and 0.04 microstrain/yr.The dilatation and maximum shear strain rates reveal the spatial coverage of strike-slip duplex and backthrust tectonics along the Mentawai Forearc Sliver.展开更多
The Global Navigation Satellite System (GNSS) is widely utilized for accurate positioning.One commonly applied method to obtain precise coordinate estimates is by implementing the relative positioning in network mode....The Global Navigation Satellite System (GNSS) is widely utilized for accurate positioning.One commonly applied method to obtain precise coordinate estimates is by implementing the relative positioning in network mode.However,this approach can be complex and challenging.Fortunately,The Japan Aerospace Exploration Agency (JAXA) offers freely available satellite orbit and clock correction products called Multi-GNSS Advanced Demonstration Tool for Orbit and Clock Analysis (MADOCA),which can enhance positioning accuracy through the precise point positioning (PPP) method.This study focuses on evaluating PPP static mode positioning using MADOCA products and comparing the results with the highly precise relative positioning method.By analyzing a network of 20 GNSS stations in Indonesia,we found that the PPP method using MADOCA products provided favorable positioning estimates.The median discrepancies and the corresponding median absolute deviation (MAD) for easting,northing,and up components were estimated as 9±18 mm,10±9 mm,and 3±40 mm,respectively.These results indicate that PPP with MADOCA products can be a reliable alternative for establishing Indonesia's horizontal control networks,particularly for orders 0,1,2,and 3,and for a broad spectrum of geoscience monitoring activities.However,considerations such as epoch transformations and seismic activities should be taken into account for accurate positioning applications that comply with the definition of the national reference framework.展开更多
Mount Semeru,an active volcano in East Java,Indonesia,erupted on December 4,2021,following extreme rainfall that caused an avalanche of hot pyroclastic flows and lava.The tropospheric conditions and dominant particle ...Mount Semeru,an active volcano in East Java,Indonesia,erupted on December 4,2021,following extreme rainfall that caused an avalanche of hot pyroclastic flows and lava.The tropospheric conditions and dominant particle components in the atmosphere can be monitored using Global Navigation Satellite System(GNSS)technology and remote sensing satellites.GNSS signal propagation delay in Precise Point Positioning(PPP)processing can be used to determine Zenith Tropospheric Delay(ZTD)and Precipitable Water Vapor(PWV)variables so that atmospheric conditions can be generated.In addition,by using remote sensing satellite data,it is possible to obtain rainfall data with high temporal resolution as well as the dominant particle and gas content values during eruptions.During the eruption period,the high value of PWV was dominated by the high intensity of precipitation during the rainy season.High rainfall before the eruption caused activity inside the mountain to increase,which occurred in avalanche type eruption.Apart from that,the atmosphere around Semeru was also dominated by SO_(2)content,which spreaded for tens of kilometers.SO_(2)content began to be detected significantly by remote sensing sensors on December 7,2021.In this study,deformation and atmospheric monitoring were also carried out using low-cost GNSS at the Semeru Monitoring Station on September 9-15,2022.The results of the ZTD and ZWD values show the dominance of the wet component,which is directly proportional to rainfall activity in this period.展开更多
Research on strain anomalies and large earthquakes based on temporal and spatial crustal activities has been rapidly growing due to data availability, especially in Japan and Indonesia. However, many research works us...Research on strain anomalies and large earthquakes based on temporal and spatial crustal activities has been rapidly growing due to data availability, especially in Japan and Indonesia. However, many research works used local-scale case studies that focused on a specific earthquake characteristic using knowledgedriven techniques, such as crustal deformation analysis. In this study, a data-driven-based analysis is used to detect anomalies using displacement rates and deformation pattern features extracted from daily global navigation satellite system(GNSS) data using a machine learning algorithm. The GNSS data with188 and 1181 continuously operating reference stations from Indonesia and Japan, respectively, are used to identify the anomaly of recent major earthquakes in the last two decades. Feature displacement rates and deformation patterns are processed in several window times with 2560 experiment scenarios to produce the best detection using tree-based algorithms. Tree-based algorithms with a single estimator(decision tree), ensemble bagging(bagging, random forest and Extra Trees), and ensemble boosting(AdaBoost, gradient boosting, LGBM, and XGB) are applied in the study. The experiment test using realtime scenario GNSSdailydatareveals high F1-scores and accuracy for anomaly detection using slope windowing 365 and 730 days of 91-day displacement rates and then 7-day deformation pattern features in tree-based algorithms. The results show the potential for medium-term anomaly detection using GNSS data without the need for multiple vulnerability assessments.展开更多
65 km Semangko Fault is part of southern segments of Sumatran Fault Zone(SFZ)which is complex corresponds to the transition from the strike-slip regime of the SFZ to the normal faulting tectonics of the Sunda Strait.T...65 km Semangko Fault is part of southern segments of Sumatran Fault Zone(SFZ)which is complex corresponds to the transition from the strike-slip regime of the SFZ to the normal faulting tectonics of the Sunda Strait.The recent publication showed branches of Semangko Fault:West Semangko Fault(WSF)and East Semangko Fault(ESF).This study estimated geodetic slip rate and locking depth of ESF using Global Positioning System(GPS)time series data from 2007 to 2019 from all available GPS sites.GPS velocities refer to Sundaland Plate were used to estimate the fault parameters of the WSF and ESF simultaneously.Non-uniformity of velocity direction shows the complexities of Semangko Fault possibly caused by the contribution of all faults around ESF.An ESF geodetic slip rate,which is 12.5±2 mm/yr was lower than WSF,which is 16.5±2 mm/yr.It is consistent with the rigid block nature of the SFZ system as northern segment slip rates have similar value.Small slip rates are possibly leading to lower generated seismic moment than the major segment of SFZ.展开更多
The eastern part of Java Island is transversed by major faults such as Cepu,Blumbang,Surabaya,and Waru Segment,part of the Kendeng Fault,Wonsorejo Fault,Pasuruan Fault,and Probolinggo Fault.Due to the major fault,we u...The eastern part of Java Island is transversed by major faults such as Cepu,Blumbang,Surabaya,and Waru Segment,part of the Kendeng Fault,Wonsorejo Fault,Pasuruan Fault,and Probolinggo Fault.Due to the major fault,we used decomposition of identified fault from the Global Navigation Satellite System(GNSS)observation data to identify the potential of local deformation.We analyzed surface deformation due to the effect of major fault using scaling law and elastic half-space method.We investigated the possibility of unidentified fault using strain rates based on velocity vector data before and after correcting the effect of a major fault.We found that strain calculation for principal strain value in the eastern part of Java Island is less than one microstrain/year and the dominant one with a compression pattern due to the Sunda subduction zone.The maximum shear strain rate value goes from 0.002 to 0.094 microstrain/year,and the dilatation rate value ranges from-0.141 to 0.038 microstrain/year,which correlates with the reverse of the Kendeng Fault.A higher compression pattern outside the major fault in a differential maximum shear strain rate might indicate a local fault.展开更多
The 2019 M_(W)6.9 Banten Intraslab earthquake occurred at~100 km to the northeast of the Sunda Trench with two nodal plane models estimated by the Global Centroid-Moment-Tensor(GCMT)Project with a strike of 200°a...The 2019 M_(W)6.9 Banten Intraslab earthquake occurred at~100 km to the northeast of the Sunda Trench with two nodal plane models estimated by the Global Centroid-Moment-Tensor(GCMT)Project with a strike of 200°and a dip of 65°.Continuous GPS data from 11 GPS sites were used to model the source of the earthquake in three-components.The coseismic displacements and its uncertainties are obtained from the coordinates of these GPS sites from 7 days before to 7 days after the earthquake.The coseismic slip is the inversion result of those displacements based on the best fit in an elastic half-space.The maximum displacement is~5 cm with a large uncertainty that is comparable to the amplitude of displacement.A seismic moment of the best model(strike of 65°and dip of 54°)is 2.79×10^(19) Nm or equivalent to M_(W)6.89.The fault model of the earthquake is highly presumed as a continuation of Sumatran Fault Zone.展开更多
The Global Navigation Satellite System(GNSS)positioning method has been significantly developed in geodetic surveying.However,the height obtained through GNSS observations is given in a geodetic height system that nee...The Global Navigation Satellite System(GNSS)positioning method has been significantly developed in geodetic surveying.However,the height obtained through GNSS observations is given in a geodetic height system that needs to be converted to orthometric height for engineering applications.Information on geoid height,which can be calculated using the global geopotential mode,is required to convert such GNSS observations into orthometric height.However,its accuracy is still insufficient for most engineering purposes.Therefore,a reliable geoid model is essential,especially in areas growing fast,e.g.,the central part of Java,Indonesia.In this study,we modeled the local geoid model in the central part of Java,Indonesia,using terrestrial-based gravity observations.The Stokes'formula with the second Helmert's condensation method under the Remove-Compute-Restore approach was implemented to model the geoid.The comparison between our best-performing geoid model and GNSS/leveling observations showed that the standard deviation of the geoid height differences was estimated to be 4.4 cm.This geoid result outperformed the commonly adopted global model of EGM2008 with the estimated standard deviation of geoid height differences of 10.7 cm.展开更多
The Java earthquake occurred on July 17, 2006 with magnitude 7.8 associated to the subduction process of Indo-Australian plate and Sundaland block off southwestern coast of Java. We present postseismic deformation par...The Java earthquake occurred on July 17, 2006 with magnitude 7.8 associated to the subduction process of Indo-Australian plate and Sundaland block off southwestern coast of Java. We present postseismic deformation parameters of the 2006 Java earthquake analyzed using campaign GPS observation from 2006 to 2008 and continuous observation from 2007 to 2014. We use an analytical approach of logarithmic and exponential functions to model these GPS data. We find that the decay time in the order of hundreds of days after the mainshock as observed by 8 years＇ data after the mainshock for magnitude 7 earthquake is longer than a general megathrust earthquake event. Our findings suggest that the 2006 Java earthquake which is considered as ＂tsunami earthquake＂ most probably occurred in the region that has low rigidity and tends to continuously slip for long time periods.展开更多
Continuous global positioning system （GPS） in northern Sumatra detected signal of the ongoing physical process of postseismic deformation after the M9.2 2004 Sumatra-Andaman earthquake. We analyze the character- ist...Continuous global positioning system （GPS） in northern Sumatra detected signal of the ongoing physical process of postseismic deformation after the M9.2 2004 Sumatra-Andaman earthquake. We analyze the character- istics of postseismic deformation of the 2004 earthquake based on GPS networks operated by BIG, and the others named AGNeSS, and SuGAr networks located in northern Sumatra. We use a simple analytical logarithmic and exponential function to evaluate the postseismic deforma- tion parameters of the 2004 earthquake. We find that GPS data in northern Sumatra during time periods of 2005-2012 are fit better using the logarithmic function with dog of 104.2 ± 0.1 than using the exponential function. Our result clearly indicates that other physical mechanisms of post- seismic deformation should be taken into account rather than a single physical mechanism of afterslip only.展开更多
A major problem associated with marine spatial planning(MSP)involves the difficult and time-consuming practice of creating a scenario that encompasses complex datasets in near real time via the use of a simple spatial...A major problem associated with marine spatial planning(MSP)involves the difficult and time-consuming practice of creating a scenario that encompasses complex datasets in near real time via the use of a simple spatial analysis method.Moreover,decision-makers require a reliable,user-friendly system to quickly and accessibly acquire accurate spatial planning information.The development of national spatial data infrastructure(NSDI),which links the spatial data of a nation’s many diverse institutions,may pave the way for the development of a tool that can better utilize spatial datasets,such as a spatial decision support system(SDSS).Thus,this project aimed to develop an SDSS for MSP and to evaluate the feasibility of its integration within the NSDI framework.The seaweed culture was selected as an example due to its economic and technological acceptance by traditional fishers.Additionally,a multicriteria analysis was used to develop the tool.Furthermore,a feasibility evaluation of its implementation within the NSDI framework was conducted based on the Delphi method.The results of the assessment indicated that the SDSS can be incorporated into the NSDI framework by addressing the policy issue–one map policy,updating custodians’decree and data,and improve the standard and protocol.展开更多
基金JSPS KAKENHI Grant Number16H06286 supports global GNSS ionospheric maps (TEC,ROTI,and detrended TEC maps) developed by the Institute for SpaceEarth Environmental Research (ISEE) of Nagoya Universitysupport of the 2024 JASSO Follow-up Research Fellowship Program for a 90-day visiting research at the Institute for Space-Earth Environmental Research (ISEE),Nagoya University+3 种基金the support received from Telkom University under the“Skema Penelitian Terapan Periode I Tahun Anggaran 2024”the Memorandum of Understanding for Research Collaboration on Regional Ionospheric Observation (No:092/SAM3/TE-DEK/2021)the National Institute of Information and Communications Technology (NICT) International Exchange Program 2024-2025(No.2024-007)support for a one-year visiting research at Hokkaido University
文摘This paper highlights the crucial role of Indonesia’s GNSS receiver network in advancing Equatorial Plasma Bubble(EPB)studies in Southeast and East Asia,as ionospheric irregularities within EPB can disrupt GNSS signals and degrade positioning accuracy.Managed by the Indonesian Geospatial Information Agency(BIG),the Indonesia Continuously Operating Reference Station(Ina-CORS)network comprises over 300 GNSS receivers spanning equatorial to southern low-latitude regions.Ina-CORS is uniquely situated to monitor EPB generation,zonal drift,and dissipation across Southeast Asia.We provide a practical tool for EPB research,by sharing two-dimensional rate of Total Electron Content(TEC)change index(ROTI)derived from this network.We generate ROTI maps with a 10-minute resolution,and samples from May 2024 are publicly available for further scientific research.Two preliminary findings from the ROTI maps of Ina-CORS are noteworthy.First,the Ina-CORS ROTI maps reveal that the irregularities within a broader EPB structure persist longer,increasing the potential for these irregularities to migrate farther eastward.Second,we demonstrate that combined ROTI maps from Ina-CORS and GNSS receivers in East Asia and Australia can be used to monitor the development of ionospheric irregularities in Southeast and East Asia.We have demonstrated the combined ROTI maps to capture the development of ionospheric irregularities in the Southeast/East Asian sector during the G5 Geomagnetic Storm on May 11,2024.We observed simultaneous ionospheric irregularities in Japan and Australia,respectively propagating northwestward and southwestward,before midnight,whereas Southeast Asia’s equatorial and low-latitude regions exhibited irregularities post-midnight.By sharing ROTI maps from Indonesia and integrating them with regional GNSS networks,researchers can conduct comprehensive EPB studies,enhancing the understanding of EPB behavior across Southeast and East Asia and contributing significantly to ionospheric research.
基金the National Institute of Information and Communication Technology International Exchange Program 2024−2025(No.2024−007)for their invaluable support in this research.3D tomography software is available at Prof.Kosuke Heki’s(Hokkaido University,Japan)personal homepage(https://www.ep.sci.hokudai.ac.jp/~heki/software.htm).support from the 2024 Japan Student Services Organization Research Follow-up Fellowship for a 90-day research visit at the Institute for Space−Earth Environmental Research,Nagoya University,Japan.PA also acknowledges the support received from Telkom University under the“Skema Penelitian Terapan Periode I Tahun Anggaran 2024”,and the Memorandum of Understanding for Research Collaboration on Regional Ionospheric Observation(No:092/SAM3/TE-DEK/2021).
文摘Equatorial Plasma Bubbles(EPBs)are ionospheric irregularities that take place near the magnetic equator.EPBs most commonly occur after sunset during the equinox months,although they can also be observed during other seasons.The phenomenon significantly disrupts radio wave signals essential to communication and navigation systems.The national network of Global Navigation Satellite System(GNSS)receivers in Indonesia(>30°longitudinal range)provides an opportunity for detailed EPB studies.To explore this,we conducted preliminary 3D tomography of total electron content(TEC)data captured by GNSS receivers following a geomagnetic storm on December 3,2023,when at least four EPB clusters occurred in the Southeast Asian sector.TEC and extracted TEC depletion with a 120-minute running average were then used as inputs for a 3D tomography program.Their 2D spatial distribution consistently captured the four EPB clusters over time.These tomography results were validated through a classical checkerboard test and comparisons with other ionospheric data sources,such as the Global Ionospheric Map(GIM)and International Reference Ionosphere(IRI)profile.Validation of the results demonstrates the capability of the Indonesian GNSS network to measure peak ionospheric density.These findings highlight the potential for future three-dimensional research of plasma bubbles in low-latitude regions using existing GNSS networks,with extensive longitudinal coverage.
基金funded by National Science Foundation of China(42025401)National Key Research and Development Program of China(2022YFB3903800)。
文摘Precise coseismic displacements in earthquake/tsunamic early warning are necessary to characterize earthquakes in real time in order to enable decision-makers to issue alerts for public safety.Real-time global navigation satellite systems(GNSSs)have been a valuable tool in monitoring seismic motions,allowing permanent displacement computation to be unambiguously achieved.As a valuable tool presented to the seismic commu nity,the GSeisRT software developed by Wuhan University(China)can realize multi-GNSS precise point positioning with ambiguity resolution(PPP-AR)and achieve centimeterlevel to sub-centimeter-level precision in real time.While the stable maintenance of a global precise point positioning(PPP)service is challenging,this software is capable of estimating satellite clocks and phase biases in real time using a regional GNSS network.This capability makes GSeisRT especially suitable for proprietary GNSS networks and,more importantly,the highest possible positio ning precision and reliability can be obtained.According to real-time results from the Network of the Americas,the mean root mean square(RMS)errors of kinematic PPP-AR over a 24 h span are as low as 1.2,1.3,and 3.0 cm in the east,north,and up components,respectively.Within the few minutes that span a typical seismic event,a horizontal displacement precision of 4 mm can be achieved.The positioning precision of the GSeisRT regional PPP/PPP-AR is 30%-40%higher than that of the global PPP/PPP-AR.Since 2019,GSeisRT has successfully recorded the static,dynamic,and peak ground displacements for the 2020Oaxaca,Mexico moment magnitude(Mw)7.4 event;the 2020 Lone Pine,California Mw 5.8 event;and the 2021 Qinghai,China Mw 7.3 event in real time.The resulting immediate magnitude estimates have an error of around 0.1 only.The GSeisRT software is open to the scientific community and has been applied by the China Earthquake Ne tworks Center,the EarthScope Consortium of the United States,the National Seismological Center of Chile,Institute of Geological and Nuclear Sciences Limited(GNS Science Te PūAo)of New Zealand,and the Geospatial Information Agency of Indonesia.
基金supported by Universitas Gadjah Mada through the 2022 Indonesian Collaborative Research Program.
文摘The Mentawai Forearc Sliver(MFS)is characterized by oblique deformation formed as slip partitioned between normal and parallel trench plate convergence.The surge of great earthquakes from 2004 to2012 along the adjacent Sunda trench left a large unbroken segment known as the Mentawai Seismic Gap.Here,we adopted continuous Global Navigation Satellite System(GNSS)observation data to identify the present regional crustal deformation using geodetic strain rates.The principal strain rate,dilatation rate,and maximum shear strain rate are about 0.13 microstrain/yr,0.2 microstrain/yr,and 0.1 microstrain/yr,respectively,with the range of its uncertainties between 0.01 and 0.04 microstrain/yr.The dilatation and maximum shear strain rates reveal the spatial coverage of strike-slip duplex and backthrust tectonics along the Mentawai Forearc Sliver.
文摘The Global Navigation Satellite System (GNSS) is widely utilized for accurate positioning.One commonly applied method to obtain precise coordinate estimates is by implementing the relative positioning in network mode.However,this approach can be complex and challenging.Fortunately,The Japan Aerospace Exploration Agency (JAXA) offers freely available satellite orbit and clock correction products called Multi-GNSS Advanced Demonstration Tool for Orbit and Clock Analysis (MADOCA),which can enhance positioning accuracy through the precise point positioning (PPP) method.This study focuses on evaluating PPP static mode positioning using MADOCA products and comparing the results with the highly precise relative positioning method.By analyzing a network of 20 GNSS stations in Indonesia,we found that the PPP method using MADOCA products provided favorable positioning estimates.The median discrepancies and the corresponding median absolute deviation (MAD) for easting,northing,and up components were estimated as 9±18 mm,10±9 mm,and 3±40 mm,respectively.These results indicate that PPP with MADOCA products can be a reliable alternative for establishing Indonesia's horizontal control networks,particularly for orders 0,1,2,and 3,and for a broad spectrum of geoscience monitoring activities.However,considerations such as epoch transformations and seismic activities should be taken into account for accurate positioning applications that comply with the definition of the national reference framework.
基金the Indonesian Collaborative Research(RKI)2022:598/IT2/T/HK.00.01/2022Center of Volcanology and Geological Hazard Mitigation of Indonesia for the data and financial support of this research。
文摘Mount Semeru,an active volcano in East Java,Indonesia,erupted on December 4,2021,following extreme rainfall that caused an avalanche of hot pyroclastic flows and lava.The tropospheric conditions and dominant particle components in the atmosphere can be monitored using Global Navigation Satellite System(GNSS)technology and remote sensing satellites.GNSS signal propagation delay in Precise Point Positioning(PPP)processing can be used to determine Zenith Tropospheric Delay(ZTD)and Precipitable Water Vapor(PWV)variables so that atmospheric conditions can be generated.In addition,by using remote sensing satellite data,it is possible to obtain rainfall data with high temporal resolution as well as the dominant particle and gas content values during eruptions.During the eruption period,the high value of PWV was dominated by the high intensity of precipitation during the rainy season.High rainfall before the eruption caused activity inside the mountain to increase,which occurred in avalanche type eruption.Apart from that,the atmosphere around Semeru was also dominated by SO_(2)content,which spreaded for tens of kilometers.SO_(2)content began to be detected significantly by remote sensing sensors on December 7,2021.In this study,deformation and atmospheric monitoring were also carried out using low-cost GNSS at the Semeru Monitoring Station on September 9-15,2022.The results of the ZTD and ZWD values show the dominance of the wet component,which is directly proportional to rainfall activity in this period.
基金the Program PenelitianKolaborasi Indonesia(PPKI)Non APBN Universitas Diponegoro Universitas Diponegoro Indonesia under Grant 117-03/UN7.6.1/PP/2021.
文摘Research on strain anomalies and large earthquakes based on temporal and spatial crustal activities has been rapidly growing due to data availability, especially in Japan and Indonesia. However, many research works used local-scale case studies that focused on a specific earthquake characteristic using knowledgedriven techniques, such as crustal deformation analysis. In this study, a data-driven-based analysis is used to detect anomalies using displacement rates and deformation pattern features extracted from daily global navigation satellite system(GNSS) data using a machine learning algorithm. The GNSS data with188 and 1181 continuously operating reference stations from Indonesia and Japan, respectively, are used to identify the anomaly of recent major earthquakes in the last two decades. Feature displacement rates and deformation patterns are processed in several window times with 2560 experiment scenarios to produce the best detection using tree-based algorithms. Tree-based algorithms with a single estimator(decision tree), ensemble bagging(bagging, random forest and Extra Trees), and ensemble boosting(AdaBoost, gradient boosting, LGBM, and XGB) are applied in the study. The experiment test using realtime scenario GNSSdailydatareveals high F1-scores and accuracy for anomaly detection using slope windowing 365 and 730 days of 91-day displacement rates and then 7-day deformation pattern features in tree-based algorithms. The results show the potential for medium-term anomaly detection using GNSS data without the need for multiple vulnerability assessments.
基金funded by Institut Teknologi Sumatera Smart Mandiri 2019 Research Grant Fund No.B/364/IT9.C1/PT.01.03/2019
文摘65 km Semangko Fault is part of southern segments of Sumatran Fault Zone(SFZ)which is complex corresponds to the transition from the strike-slip regime of the SFZ to the normal faulting tectonics of the Sunda Strait.The recent publication showed branches of Semangko Fault:West Semangko Fault(WSF)and East Semangko Fault(ESF).This study estimated geodetic slip rate and locking depth of ESF using Global Positioning System(GPS)time series data from 2007 to 2019 from all available GPS sites.GPS velocities refer to Sundaland Plate were used to estimate the fault parameters of the WSF and ESF simultaneously.Non-uniformity of velocity direction shows the complexities of Semangko Fault possibly caused by the contribution of all faults around ESF.An ESF geodetic slip rate,which is 12.5±2 mm/yr was lower than WSF,which is 16.5±2 mm/yr.It is consistent with the rigid block nature of the SFZ system as northern segment slip rates have similar value.Small slip rates are possibly leading to lower generated seismic moment than the major segment of SFZ.
基金partially supported by UGM’s Fund in the scheme of the RTA Project
文摘The eastern part of Java Island is transversed by major faults such as Cepu,Blumbang,Surabaya,and Waru Segment,part of the Kendeng Fault,Wonsorejo Fault,Pasuruan Fault,and Probolinggo Fault.Due to the major fault,we used decomposition of identified fault from the Global Navigation Satellite System(GNSS)observation data to identify the potential of local deformation.We analyzed surface deformation due to the effect of major fault using scaling law and elastic half-space method.We investigated the possibility of unidentified fault using strain rates based on velocity vector data before and after correcting the effect of a major fault.We found that strain calculation for principal strain value in the eastern part of Java Island is less than one microstrain/year and the dominant one with a compression pattern due to the Sunda subduction zone.The maximum shear strain rate value goes from 0.002 to 0.094 microstrain/year,and the dilatation rate value ranges from-0.141 to 0.038 microstrain/year,which correlates with the reverse of the Kendeng Fault.A higher compression pattern outside the major fault in a differential maximum shear strain rate might indicate a local fault.
基金funded by the Ministry of Research and Technology 2020 Research Grant Fund No.B/201/IT9.C1/PT.01.03/2020。
文摘The 2019 M_(W)6.9 Banten Intraslab earthquake occurred at~100 km to the northeast of the Sunda Trench with two nodal plane models estimated by the Global Centroid-Moment-Tensor(GCMT)Project with a strike of 200°and a dip of 65°.Continuous GPS data from 11 GPS sites were used to model the source of the earthquake in three-components.The coseismic displacements and its uncertainties are obtained from the coordinates of these GPS sites from 7 days before to 7 days after the earthquake.The coseismic slip is the inversion result of those displacements based on the best fit in an elastic half-space.The maximum displacement is~5 cm with a large uncertainty that is comparable to the amplitude of displacement.A seismic moment of the best model(strike of 65°and dip of 54°)is 2.79×10^(19) Nm or equivalent to M_(W)6.89.The fault model of the earthquake is highly presumed as a continuation of Sumatran Fault Zone.
文摘The Global Navigation Satellite System(GNSS)positioning method has been significantly developed in geodetic surveying.However,the height obtained through GNSS observations is given in a geodetic height system that needs to be converted to orthometric height for engineering applications.Information on geoid height,which can be calculated using the global geopotential mode,is required to convert such GNSS observations into orthometric height.However,its accuracy is still insufficient for most engineering purposes.Therefore,a reliable geoid model is essential,especially in areas growing fast,e.g.,the central part of Java,Indonesia.In this study,we modeled the local geoid model in the central part of Java,Indonesia,using terrestrial-based gravity observations.The Stokes'formula with the second Helmert's condensation method under the Remove-Compute-Restore approach was implemented to model the geoid.The comparison between our best-performing geoid model and GNSS/leveling observations showed that the standard deviation of the geoid height differences was estimated to be 4.4 cm.This geoid result outperformed the commonly adopted global model of EGM2008 with the estimated standard deviation of geoid height differences of 10.7 cm.
基金partially supported by the Australian Department of Foreign Affairs and Trade(DFAT)for Graduate Research on Earthquake and Active Tectonics at the Bandung Institute of Technology and Research Program of Bandung Institute of Technology No.FITB.PN-06-01-2016
文摘The Java earthquake occurred on July 17, 2006 with magnitude 7.8 associated to the subduction process of Indo-Australian plate and Sundaland block off southwestern coast of Java. We present postseismic deformation parameters of the 2006 Java earthquake analyzed using campaign GPS observation from 2006 to 2008 and continuous observation from 2007 to 2014. We use an analytical approach of logarithmic and exponential functions to model these GPS data. We find that the decay time in the order of hundreds of days after the mainshock as observed by 8 years＇ data after the mainshock for magnitude 7 earthquake is longer than a general megathrust earthquake event. Our findings suggest that the 2006 Java earthquake which is considered as ＂tsunami earthquake＂ most probably occurred in the region that has low rigidity and tends to continuously slip for long time periods.
基金funded by the PLN APJ of Sukabumi No.203/060/APJ-SKI/2010Indonesia Endowment Fund for Education(LPDP) No.PRJ1048/LPDP/2015the Australian Department of Foreign Affairs and Trade(DFAT) for Graduate Research on Earthquake and Active Tectonics at the Bandung Institute of Technology
文摘Continuous global positioning system （GPS） in northern Sumatra detected signal of the ongoing physical process of postseismic deformation after the M9.2 2004 Sumatra-Andaman earthquake. We analyze the character- istics of postseismic deformation of the 2004 earthquake based on GPS networks operated by BIG, and the others named AGNeSS, and SuGAr networks located in northern Sumatra. We use a simple analytical logarithmic and exponential function to evaluate the postseismic deforma- tion parameters of the 2004 earthquake. We find that GPS data in northern Sumatra during time periods of 2005-2012 are fit better using the logarithmic function with dog of 104.2 ± 0.1 than using the exponential function. Our result clearly indicates that other physical mechanisms of post- seismic deformation should be taken into account rather than a single physical mechanism of afterslip only.
文摘A major problem associated with marine spatial planning(MSP)involves the difficult and time-consuming practice of creating a scenario that encompasses complex datasets in near real time via the use of a simple spatial analysis method.Moreover,decision-makers require a reliable,user-friendly system to quickly and accessibly acquire accurate spatial planning information.The development of national spatial data infrastructure(NSDI),which links the spatial data of a nation’s many diverse institutions,may pave the way for the development of a tool that can better utilize spatial datasets,such as a spatial decision support system(SDSS).Thus,this project aimed to develop an SDSS for MSP and to evaluate the feasibility of its integration within the NSDI framework.The seaweed culture was selected as an example due to its economic and technological acceptance by traditional fishers.Additionally,a multicriteria analysis was used to develop the tool.Furthermore,a feasibility evaluation of its implementation within the NSDI framework was conducted based on the Delphi method.The results of the assessment indicated that the SDSS can be incorporated into the NSDI framework by addressing the policy issue–one map policy,updating custodians’decree and data,and improve the standard and protocol.
