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
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
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
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 scale-invariant feature transform(SIFT)ability to automatic control points(CPs)extraction is very well known on remote sensing images,however,its result inaccurate and sometimes has incorrect matching from generat...The scale-invariant feature transform(SIFT)ability to automatic control points(CPs)extraction is very well known on remote sensing images,however,its result inaccurate and sometimes has incorrect matching from generating a small number of false CPs pairs,their matching has high false alarm.This paper presents a method containing a modification to improve the performance of the SIFT CPs matching by applying sum of absolute difference(SAD)in different manner for the new optical satellite generation called near-equatorial orbit satellite(NEqO)and multi-sensor images.The proposed method leads to improving CPs matching with a significantly higher rate of correct matches.The data in this study were obtained from the RazakSAT satellite covering the Kuala Lumpur-Pekan area.The proposed method consists of three parts:(1)applying the SIFT to extract CPs automatically,(2)refining CPs matching by SAD algorithm with empirical threshold,and(3)evaluating the refined CPs scenario by comparing the result of the original SIFT with that of the proposed method.The result indicates an accurate and precise performance of the model,which showed the effectiveness and robustness of the proposed approach.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 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
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
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
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.
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.
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.
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.
文摘The scale-invariant feature transform(SIFT)ability to automatic control points(CPs)extraction is very well known on remote sensing images,however,its result inaccurate and sometimes has incorrect matching from generating a small number of false CPs pairs,their matching has high false alarm.This paper presents a method containing a modification to improve the performance of the SIFT CPs matching by applying sum of absolute difference(SAD)in different manner for the new optical satellite generation called near-equatorial orbit satellite(NEqO)and multi-sensor images.The proposed method leads to improving CPs matching with a significantly higher rate of correct matches.The data in this study were obtained from the RazakSAT satellite covering the Kuala Lumpur-Pekan area.The proposed method consists of three parts:(1)applying the SIFT to extract CPs automatically,(2)refining CPs matching by SAD algorithm with empirical threshold,and(3)evaluating the refined CPs scenario by comparing the result of the original SIFT with that of the proposed method.The result indicates an accurate and precise performance of the model,which showed the effectiveness and robustness of the proposed approach.
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 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.
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.
