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2020, Earthquake Spectra
Indonesia is one of the most seismically active countries in the world, and its large, vulnerable population makes reliable seismic hazard assessment an urgent priority. In 2016, the Indonesian Ministry of Public Works and Housing established a team of earthquake scientists and engineers tasked with improving the input data available for revising the national seismic hazard map. They compiled results of recent active fault studies using geological, geophysical, and geodetic observations, as well as a new comprehensive earthquake catalog including hypocenters relocated in a three-dimensional velocity model. Seismic hazard analysis was undertaken using recently developed ground motion prediction equations (GMPEs), and logic trees for the inclusion of epistemic uncertainty associated with different choices for GMPEs and earthquake recurrence models. The new seismic hazard maps establish the importance of active faults and intraslab seismicity, as well as the subduction megathrust, in d...
Tectonophysics, 2004
The ground motion hazard for Sumatra and the Malaysian peninsula is calculated in a probabilistic framework, using procedures developed for the US National Seismic Hazard Maps. We constructed regional earthquake source models and used standard published and modified attenuation equations to calculate peak ground acceleration at 2% and 10% probability of exceedance in 50 years for rock site conditions. We developed or modified earthquake catalogs and declustered these catalogs to include only independent earthquakes. The resulting catalogs were used to define four source zones that characterize earthquakes in four tectonic environments: subduction zone interface earthquakes, subduction zone deep intraslab earthquakes, strike-slip transform earthquakes, and intraplate earthquakes. The recurrence rates and sizes of historical earthquakes on known faults and across zones were also determined from this modified catalog. In addition to the source zones, our seismic source model considers two major faults that are known historically to generate large earthquakes: the Sumatran subduction zone and the Sumatran transform fault. Several published studies were used to describe earthquakes along these faults during historical and pre-historical time, as well as to identify segmentation models of faults. Peak horizontal ground accelerations were calculated using ground motion prediction relations that were developed from seismic data obtained from the crustal interplate environment, crustal intraplate environment, along the subduction zone interface, and from deep intraslab earthquakes. Most of these relations, however, have not been developed for large distances that are needed for calculating the hazard across the Malaysian peninsula, and none were developed for earthquake ground motions generated in an interplate tectonic environment that are propagated into an intraplate tectonic environment. For the interplate and intraplate crustal earthquakes, we have applied ground-motion prediction relations that are consistent with California (interplate) and India (intraplate) strong motion data that we collected for distances beyond 200 km. For the subduction zone equations, we recognized that the published relationships at large distances were not consistent with global earthquake data that we collected and modified the relations to be compatible with the global subduction zone ground motions. In this analysis, we have used alternative source and (M.D. Petersen).
10th International Conference on Urban Earthquake Engineering March 1-2, 2013, Tokyo Institute of Technology, Tokyo, Japan
The new Indonesia Seismic Hazard Maps for revising the previous map in SNI 03-1726-2002 was published in July 2010. These maps developed by Team for Revision of Seismic Hazard Maps of Indonesia were based on probabilistic approach for 2% probability of exceedance (PE) in 50 years and deterministic approach by using three-dimensional seismic source models and by considering latest geological and seismological data and fragility curve of buildings. Seismic sources were represented by subduction, fault, and background zones. The new maps were developed based on PSHA method. A principal advantage of the probabilistic method is combining all the possible earthquakes affecting the site. This paper presents deaggregation of Indonesia Seismic Hazard Map 2010. Deaggregation for peak ground acceleration, 0.2-sec and 1.0-sec pseudo spectral acceleration (SA) is performed for 2% PE in 50 years (2475 years mean return period). The maps of mean and modal of magnitude and distance presented here are intended to provide information about the distribution of probabilistic seismic sources and to provide suggestions for seismic sources to use in developing artificial ground motion.
2016
for his kind contributions. I also thank Mr. Jack Wynker and his colleagues for their contributions by editing the thesis to ensure the appropriateness of the language. Last but not least, I want to express grateful thanks to my family; my father and mother, my father and mother-in-law, my dear wife, and my sisters and brotherin-law for their unlimited supports. Without their consistent supports and encouragement, it was impossible for me to accomplish this work. v
International Journal of Computer and Electrical Engineering, 2013
This study focuses on investigation which published Ground Motion Prediction Equations (GMPE) are appropriate to use in Indonesian earthquake hazard assessment, especially for study area in Sumatra-Java region. The relevant GMPEs compared in this study are based on the resemblance of geologic and tectonic conditions of the regions where the GMPEs were developed to the study area. Twelve GMPEs have been considered in this study, consisting of nine GMPEs derived for subduction-zone event types (intraslab and interface regimes) and three GMPEs derived for the crustal regime. The analysis of GMPEs in this study was done using the graphical analysis of residuals between the observed ground motion value and the corresponding values predicted by each GMPE. The visual analysis of the statistical graphs presented in this study indicates four GMPEs (Youngs (1997), Zhao (2006), Kanno (2006) and Lin-Lee (2008) match with the recorded data reasonably well, while the others have poor ft with the data. Inthis study, we also rank the GMPEsusing the quantitative method proposed by Scherbaum et.al (2004). The Scherbaum e.al (2004) scheme shows that comparison of PGA/PSA with threshold value 0.0005 m/s2 gives a better output than using all data. In this study, we found that among all models, only the Youngs (1997) and Zhao (2006) models provide predictions consistent with the data from BMKG's network.
The U.S. Geological Survey (USGS) Southeast Asia Seismic Hazard Project originated in response to the 26 December 2004 Sumatra earthquake (M9.2) and the resulting tsunami that caused significant casualties and economic losses in Indonesia, Thailand, Malaysia, India, Sri Lanka, and the Maldives. Hazard models and maps were produced, with input from several international science organizations, by the USGS in Golden, Colo., for the region encompassing Thailand, Malaysia, Singapore and eastern Indonesia using the methodologies established for producing the United States national seismic hazard maps. A new subduction zone model was developed that considers historic seismicity, paleoseismic investigations, geodetic data, and ground motion studies. Seismicity catalogs and hazard models were updated to 2007. Fault maps were compiled and fault parameters were discussed at workshops held in Thailand, Malaysia, and Indonesia. In addition, geology and shear-wave velocity maps and a seismic risk...
2024
An earthquake was felt in the Mojokerto area, East Java (Indonesia) with a magnitude of M 4.4. This area has a low seismicity level according to the latest earthquake catalog. In this paper, we conduct a study to determine the direction of fault movement in the area, using data from BMKG seismic sensors with a distance of less than 250 km. The moment tensor inversion results show that the Strike/Dip/Rake values at each nodal plane are 257/88/4 and 167/86/175. To determine the direction of fault movement, we prefer a strike of 167 degrees for this earthquake, following the direction of deformation around the area from the northeast of Java Island. From the results of the moment tensor solution and the history of seismicity that has occurred in the area around Surabaya, it can be shown that the city of Surabaya is a city that is close to seismic activity, although it tends to have small activity, this needs to be considered considering that Surabaya is one of the cities with the highest population density in Indonesia. Further research needs to be done related to disaster vulnerability around the city of Surabaya. From the results of the source mechanism and seismicity in the Surabaya area it can be concluded that the Surabaya area has a disaster risk, there needs to be further research that discusses the local footprint effects of soil in the area in the Surabaya area. This research is needed for further discussion of the possibility of disasters in the Surabaya area.
Journal of Natural Disaster Science, 2012
Based on compiled data during the period 1779-2010, 48,000 earthquake events exceeding M4 had occurred in Indonesia. Since the earthquake data are available in various magnitude scales, we converted all scales into moment magnitude. By using the catalogs compiled, we constructed area earthquake source model and estimated the frequencymagnitude relationship. From recorded data by accelerometers installed at four stations in Padang, we plotted observed data on the several existing attenuation equations and selected a suitable attenuation relationship for Indonesia. Peak ground acceleration on 10% probability of exceedance in 50 years for rock and soft soil condition were calculated. We compared the expected acceleration with existing ones and discussed. Based on the expected acceleration calculated, we proposed design spectra in several major cities in Indonesia.
Geomechanics and …, 2010
2020
The probability difference before the occurrence of a large earthquake is mapped in the northern part of Sumatra, taking the range of Region Time Length (RTL) before a major earthquake (December 26, 2 2004) around 15 years. By normalizing the absolute value of probability difference between two periods of RTL and before RTL, the Seismic Quiescence Index (SQI) is then defined. Probability difference analysis is done by dividing observations of shallow earthquake periods into two periods based on the similarity gradient of the annual earthquake production, namely 1963-1990 and 1991-November 2004. The results showed that areas with relatively high SQI were consistent with the presence of major earthquake events after November 2004 to 2016 that are sorted by a radius of 300 km with the center point being the epicenter position of the December 2004 earthquake. The implementation of the SQI was then used for probabilistic seismic hazards study and analysis based on an integrated model that is derived based on the estimated of seismicity rate of around the subduction zone and active fault of Sumatra Fault Zone (SFZ) sources. The map of Probabilistic Seismic Hazard Analysis (PSHA) is then constructed based on Peak Ground Acceleration (PGA) estimated for a 10% Probability Exceedance (PE) level in 50 years. The results of this study may be very useful for earthquake mitigation and modeling efforts for PSHA going forward.
2008
The U.S. Geological Survey (USGS) Southeast Asia Seismic Hazard Project originated in response to the 26 December 2004 Sumatra earthquake (M9.2) and the resulting tsunami that caused significant casualties and economic losses in Indonesia, Thailand, Malaysia, India, Sri Lanka, and the Maldives. Hazard models and maps were produced, with input from several international science organizations, by the USGS in Golden, Colo., for the region encompassing Thailand, Malaysia, Singapore and eastern Indonesia using the methodologies established for producing the United States national seismic hazard maps. A new subduction zone model was developed that considers historic seismicity, paleoseismic investigations, geodetic data, and ground motion studies. Seismicity catalogs and hazard models were updated to 2007. Fault maps were compiled and fault parameters were discussed at workshops held in Thailand, Malaysia, and Indonesia. In addition, geology and shear-wave velocity maps and a seismic risk...
Rudarsko-geološko-naftni zbornik, 2024
The accurate prediction and prevention of earthquakes remains challenging. Consequently, the primary approach to mitigate the impact of earthquakes is through disaster risk reduction efforts. One significant strategy involves conducting seismic vulnerability analyses based on disaster scenarios. This study aims to identify and map areas with varying levels of seismic vulnerability, analyzing the factors contributing to vulnerability in the South Bengkulu Regency. Secondary data, including peak ground acceleration (PGA) values, were collected, along with microtremor data obtained through the Horizontal to Vertical Spectral Ratio (HVSR) method. The recorded microtremor data serve as input parameters for PGA, Modified Mercalli Intensity (MMI), Seismic Vulnerability Index (K g ), shear wave velocity (V s ), and the time-averaged shear wave velocity for the first 30 m depths (V s30 ) values. The findings reveal that, overall, seismic vulnerability in the South Bengkulu Regency can be categorized as low. However, specific areas, particularly in the southwestern and northeastern zones, exhibit relatively higher levels of vulnerability. The heightened vulnerability in these areas is attributed to elevated PGA values, despite the region's generally high soil density, which acts as a mitigating factor against earthquake threats.
The probabilistic seismic hazard maps are developed for Yogyakarta depression area. The earthquake catalog of ANSS (1970ANSS ( -2007 is taken into account. On the basis of seismicity of the area, tectonics and geological information, the seismic source zones are characterized for this area. The seismicity parameters of each seismic source are determined by applying the classical Gutenberg-Richter recurrence model, regarding the historical records. The attenuation relation for Yogyakarta depression area cannot be evaluated since the sufficient strong ground motion records are not available for this region. Therefore the attenuation relations which were developed for other territories as Europe and Japan are used for the present hazard calculation by validating, using the aftershocks records, modeling the peak ground acceleration maps for the recent event, 27 May, 2006, Yogyakarta earthquake inserting the damage area distribution pattern. The probabilistic seismic hazard maps are finally developed by using EQRISK computer program by modifying for the present purpose. The seismic hazard maps expressed in term of peak ground acceleration (PGA) are developed for the recurrence intervals of 10, 50, 100, 200 and 500 years.
Seismological …, 2010
Natural Hazards and Earth System Sciences, 2018
Seismic hazard assessments, both deterministic and probabilistic, for Peninsular Malaysia have been carried out using peak ground acceleration (PGA) data recorded between 2004 and 2016 by the Malaysian Meteorological Department using triaxial accelerometers placed at 19 seismic stations on the peninsula. Seismicity source modelling for the deterministic seismic hazard assessment (DSHA) used historical point sources whereas in the probabilistic (PSHA) approach, line and areal sources were used. The earthquake sources comprised the Sumatran subduction zone (SSZ), Sumatran fault zone (SFZ) and local intraplate (LI) faults. Gutenberg-Richter law b value for the various zones identified within the SSZ ranged between 0.56 and 1.06 (mean = 0.82) and for the zones within the SFZ, between 0.57 and 1.03 (mean = 0.89). Suitable ground motion prediction equations (GMPEs) for Peninsular Malaysia along with other pertinent information were used for constructing a logic tree for PSHA of the region. The DSHA "critical-worst" scenario suggests PGAs of 0.07-0.80 ms −2 (0.7-8.2 percent g), whilst the PSHA suggests mean PGAs of 0.11-0.55 ms −2 (0.5-5.4 percent g) and 0.20-1.02 ms −2 (1.9-10.1 percent g) at 10 % and 2 % probability of exceedance in 50 years, respectively. DSHA and PSHA, despite using different source models and methodologies, both conclude that the centralwestern cities of Peninsular Malaysia, located between 2 and 4 • N, are most susceptible to high PGAs, due to neighbouring active Sumatran sources, SFZ and SSZ. Of the two Sumatran sources, surprisingly, the relatively less active SFZ source with low magnitude seismicity appeared as the major contributor due to its proximity. However, potential hazards due to SSZ mega-earthquakes should not be dismissed. Finally, DSHA performed using the limited LI seismic data from the Bukit Tinggi fault at a reasonable moment magnitude (M w) value of 5.0 predicted a PGA of ∼ 0.40 ms −2 at Kuala Lumpur.
Arabian Journal of Geosciences, 2020
Earthquake Monitoring Center (EMC) at Sultan Qaboos University (SQU) initiated evaluating the seismic hazard in the Sultanate of Oman in 2009. EMC has produced the first probabilistic and deterministic seismic hazard maps for Oman in 2012 and 2013, respectively. In the current study, the probabilistic seismic hazard assessment (PSHA) is revisited to provide an updated assessment of the seismic actions on the Sultanate. The present study has several advantages over its predecessor: using an updated homogeneous earthquake catalogue, recently developed seismic source model; inclusion of epistemic uncertainties for the source models, recurrence parameters, maximum magnitude, and more recent and applicable ground-motion prediction equations (GMPEs). Epistemic uncertainties were treated using a combination of the best available databases within a properly weighted logic tree framework. Seismic hazard maps in terms of horizontal peak ground acceleration (PGA) and 5% damped spectral accelerations (SA) at the bedrock conditions (VS = 760 m/s) for 475-and 2475-year return periods were generated using the classical Cornell-McGuire approach. Additionally, uniform hazard spectra (UHS) for the important population centers are provided. The results show higher values at the northern parts of the country compared to the hazard values obtained in the previous study.
Nucleation and Atmospheric Aerosols, 2021
Indonesia is the country with the second-highest level of seismicity in the world after Japan. During 2019 there were 11,573 tectonic earthquakes of varying magnitude and depth. With high seismicity and unpredictability when and where it will occur, it demands continued efforts to reduce its impact through disaster mitigation. One of the mitigation efforts is to map the level of risk of damage due to earthquakes. In this paper, we will learn how to make the map in West Java, Central Sulawesi, and Lombok. This area was chosen because of the relatively high level of seismicity and magnitude, as well as a large number of fatalities. Three different methods are used, namely Atkinson Boore for West Java, McGuire R.K for Central Sulawesi, and Fukushima for Lombok. The results of the analysis show that in West Java the areas that have a high level of risk of damage are Sukabumi,
Cognizance Journal of Multidisciplinary Studies (CJMS), 2024
Semarang Regency was one of the areas affected by the earthquake. This happens because it is located north of the subduction zone and has active faults, so research is needed to identify the impact of earthquakes in Semarang Regency as an initial action in disaster mitigation efforts. This research aims to determine the distribution of PGA values in the Semarang Regency area and to assess the seismic hazard due to earthquakes based on a map of the distribution of PGA values in the Semarang Regency area. The method used is the Probabilistic Seismic Hazard Analysis (PSHA) method, which uses earthquake catalogues from BMKG, USGS, IRIS, and ISC. The earthquake source data was the n processed using ZMAP and R-CRISIS software. The results of seismic hazard analysis in the Semarang Regency area for a probability of exceeding 10% in 50 years or an earthquake return period of 475 years in bedrock with a period of 0 seconds obtained a PGA value ranging from 0.368–0.844 g, for a short period of 0.2 seconds the PGA value obtained ranged from 0.647. –1.773 g, for 1 second, the PGA value obtained ranges from 0.320–0.852 g. The highest PGA value is in West Ungaran District, with a value of 0.844 g. The lowest PGA value is in Kaliwungu District, which has a value of 0.458 g. The active fault zones influence the danger of earthquakes in the Semarang Regency area in Semarang Regency.
2018
This paper presents the recent efforts in Indonesia to mitigate the impacts of earthquake hazards. The actions includes as follows: updating of the seismic hazard maps of Indonesia 2010 and 2016; revision and continuous updating of building and infrastructure design codes; development of microzonation maps for big cities in Indonesia; development of academic draft of Indonesian Earthquake Master Plan; development of design guidelines for tsunami vertical evacuation; development of a national design code for geotechnics and earthquake; and establishment of the national center for earthquake studies. Revision of seismic hazard maps for Indonesia 2010 has been developed based upon updated: seismotectonic data, fault models, and GMPEs up to 2010. The updating of infrastructure design codes related to earthquakes activities are being performed for buildings, bridges, dams, harbors and others special structures. The development of microzonation map of seismic risk has been initiated for J...
Earth, Planets and Space, 2021
We present here an analysis of the destructive Mw 6.2 earthquake sequence that took place on 14 January 2021 in Mamuju–Majene, West Sulawesi, Indonesia. Our relocated foreshocks, mainshock, and aftershocks and their focal mechanisms show that they occurred on two different fault planes, in which the foreshock perturbed the stress state of a nearby fault segment, causing the fault plane to subsequently rupture. The mainshock had relatively few aftershocks, an observation that is likely related to the kinematics of the fault rupture, which is relatively small in size and of short duration, thus indicating a high stress-drop earthquake rupture. The Coulomb stress change shows that areas to the northwest and southeast of the mainshock have increased stress, consistent with the observation that most aftershocks are in the northwest.
Geoscience Letters, 2021
The geological setting of Jakarta and its immediate surroundings are poorly understood, yet it is one of the few places in Indonesia that is impacted by earthquakes from both the Java subduction zone and active faults on land. In this study, a borehole seismic experiment with low noise characteristics was deployed to record seismic activity on the ~ E-W oriented Baribis Fault, which is ~ 130 km long, passes to the south of Jakarta, and is only ~ 20 km away at its nearest point. A primary objective of this study is to determine whether this fault is seismically active, and therefore, whether it might pose a threat to nearby population centers, including Jakarta in particular. A total of seven broadband instruments that spanned Jakarta and the surrounding region were installed between the end of July 2019 and August 2020, during which time we were able to detect and locate 91 earthquakes. Two earthquakes were located close to the Baribis Fault line, one of which was felt in Bekasi (so...
Sustainability
The Sorong–MakbonSorong–Makbon Corridor is one of the key routes connecting Sorong to other sections of the West Papua region in Indonesia. Throughout the Sorong–Makbon Corridor, roads and slopes often sustain damage. When landslides reach the road shoulder and destroy the pavement, they often prevent access to the road. In addition to the influence of surface water runoff, there are indications that earthquakes contribute to the ineffectiveness of the previous design. This seems to be accurate since the author has seen the typical movement of avalanches. Using the Probabilistic Seismic Hazard Analysis (PSHA) approach, the earthquake’s effects on this corridor were mapped out. With the use of the Indonesian earthquake data library, the Matlab-Zmap Program, and the Spectrum Response, the history of earthquakes in the Sorong–Makbon corridor was analysed to determine their velocity. This analysis reveals that the earthquake’s influence on the Sorong–Makbon corridor has an acceleration ...
Natural Hazards, 2023
The seismically active Sumatra subduction zone has generated some of the largest earthquakes in the instrumental record, and both historical accounts and paleogeodetic coral studies indicate such activity has historical recorded megathrust earthquakes and transferred stress to the surrounding, including the Great Sumatran Fault (GSF). Therefore, evaluating the stress transfer from these large subduction earthquakes could delineate the highly stressed area as potential-earthquake region along the GSF. In this study, we investigated eight megathrust earthquakes from 1797 to 2010 and resolved the accumulated Coulomb stress changes onto the 18 segments along the GSF. Additionally, we also estimated the rate of tectonic stress on the GSF segments which experienced large earthquake using the case of: (1) no sliver movement and (2) with sliver movement. Based on the historical stress changes of large earthquakes and the increase in tectonic stress rate, we analysed the historical stress changes time evolution on the GSF. The Coulomb stress accumulation of megathrust earthquakes between 1797-1907 increase the stress changes mainly on the southern part of GSF which followed by four major events between 1890-1943. The estimation of tectonic stress rates using case (1) produces low rate and long recurrence intervals which implies that the megathrust earthquakes plays an important role in allowing the GSF earthquake to occur. When implementing the arc-parallel sliver movement of case (2) to the calculation, the tectonic stress rates is 9 to 58 times higher than case (1) of no sliver movement. The observed slip rate of 15-16 mm/yr at the GSF is consistent with the recurrence interval for full-segment rupture of 100-200 years obtained from case (2). This suggests that the GSF earthquake is more controlled by the rapid arc-parallel forearc sliver motion. Furthermore, the analysis of stress changes time evolution model shows that some segments such as Tripa (North and South), Angkola, Musi and Manna appear to be brought back in their seismic cycles since these segments have experienced full-segment rupture and likely locked, increasing their earthquake hazard potentials.
Scientific Reports
Recent borehole seismic deployments conducted along the Baribis Fault in northwestern Java reveal that it may be active. In this study, we exploit these data to locate proximal earthquakes using a relative relocation technique, estimate their moment magnitudes using a spectral fitting method and compute their focal mechanisms via waveform inversion. We observe that seismicity in the eastern part of the fault is significantly higher than in the west, where a previous GPS study of the region south of Jakarta demonstrated the existence of high compression rates. These observations imply that the western Baribis Fault is locked, and that neighbouring areas, including southern Jakarta and its surroundings, may be highly vulnerable to future sizeable earthquakes when accumulated elastic strain energy is eventually released during fault rupture. Significantly, the current generation of Indonesia’s national hazard maps have not considered seismicity along the Baribis Fault. Our new results ...
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