Post-eruptive lahars at Kali Putih following the 2010 eruption of Merapi volcano,Indonesia: occurrences and impacts     

Hadmoko  Danang Sri  de Belizal  Edouard  Mutaqin  Bachtiar Wahyu  Dipayana  Gilang Arya  Marfai  Muh Aris  Lavigne  Franck  Sartohadi  Junun  Worosuprojo  Suratman  Starheim  Colette C. A.  Gomez  Christopher 《Natural Hazards》2018,94(1):419-444

Following the 2010 VEI 4 eruption of Merapi volcano, more than 250 lahars were triggered during two rainy seasons from October 2010 to March 2012. This high number of post-eruption lahars mainly occurred in the Kali (valley) Putih watershed and was mostly associated with high-magnitude rainstorms. A lahar occurring on January 8, 2011, caused significant damage to homes in several communities, bridges, sabo dams, and agricultural crops. The aims of this contribution are to document the impacts of lahars on the Kali Putih watershed and specifically (1) to analyze the lahar frequency during the period of 1969–2012 on an inter-annual and intra-annual basis and to determine the link between the volume of tephra and the frequency of lahars; (2) to detail the lahar trajectory and channel evolution following the January 8th lahar; (3) to map the spatial distribution of the thickness and geomorphic effects of the lahar deposit; and (4) to determine the impacts of the lahar on the infrastructure (sabo dams and roads) and settlements in the distal area of the volcano. The Kali Putih watershed has experienced 62 lahars, which represent 22% of all lahars triggered on 17 rivers at Merapi between 2010 and 2012. The main geomorphic impacts are: (1) excessive sedimentation in valleys, settlements and agricultural areas; (2) undercutting of the river banks by as much as 50 m, accompanied by channel widening; and (3) abrupt changes in the river channel direction in the distal area (15–20 km downstream of the volcano). About 19 sabo dams were damaged, and 3 were totally destroyed. Over 307 houses were damaged, and the National Road Yogyakarta–Semarang was regularly cut (18 times during approximately 25 days). Although the sabo dams on Kali Putih were originally constructed to protect distal areas from lahar damage, they had little effect on the 2010–2012 rain-triggered lahars. The underlying design of those dams along this river is one of the main reasons for the major destruction in this sector of the volcano’s lower slope. The catch basin capacity of the sabo dam was only 1.75?×?10⁶ m³, whereas the total volume of the 2010–2011 lahars exceeded 5?×?10⁶ m³. In order to prepare for future lahars, the government has invested in significant mitigation measures, ranging from structural approaches (e.g., building new sabo dams and developing an early warning system) to non-structural approaches (e.g., contingency and preparedness planning and hazard education).

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Comparing data-driven landslide susceptibility models based on participatory landslide inventory mapping in Purwosari area,Yogyakarta, Java     

Guruh Samodra  Guangqi Chen  Junun Sartohadi  Kiyonobu Kasama 《Environmental Earth Sciences》2017,76(4):184

There are different approaches and techniques for landslide susceptibility mapping. However, no agreement has been reached in both the procedure and the use of specific controlling factors employed in the landslide susceptibility mapping. Each model has its own assumption, and the result may differ from place to place. Different landslide controlling factors and the completeness of landslide inventory may also affect the different result. Incomplete landslide inventory may produce significance error in the interpretation of the relationship between landslide and controlling factor. Comparing landslide susceptibility models using complete inventory is essential in order to identify the most realistic landslide susceptibility approach applied typically in the tropical region Indonesia. Purwosari area, Java, which has total 182 landslides occurred from 1979 to 2011, was selected as study area to evaluate three data-driven landslide susceptibility models, i.e., weight of evidence, logistic regression, and artificial neural network. Landslide in the study area is usually affected by rainfall and anthropogenic activities. The landslide typology consists of shallow translational and rotational slide. The elevation, slope, aspect, plan curvature, profile curvature, stream power index, topographic wetness index, distance to river, land use, and distance to road were selected as landslide controlling factors for the analysis. Considering the accuracy and the precision evaluations, the weight of evidence represents considerably the most realistic prediction capacities (79%) when comparing with the logistic regression (72%) and artificial neural network (71%). The linear model shows more powerful result than the nonlinear models because it fits to the area where complete landslide inventory is available, the landscape is not varied, and the occurence of landslide is evenly distributed to the class of controlling factor.  相似文献   

Landslide hazard and risk assessment and their application in risk management and landuse planning in eastern flank of Menoreh Mountains,Yogyakarta Province,Indonesia     

Danang Sri Hadmoko  Franck Lavigne  Junun Sartohadi  Pramono Hadi  Winaryo 《Natural Hazards》2010,54(3):623-642

The Menoreh Mountains in Yogyakarta are severely affected by landslides. Due to the high population densities, mass movements are generally damaging and fatal. More than other Javanese mountains, the Menoreh Mountains cumulate several factors causing landslides. Therefore, it is necessary to evaluate the ways to map landslide risk in order to improve the risk mitigation. The objectives of this paper are to provide landslide hazard and risk assessment that will be useful for risk prevention and landuse planning in the Menoreh Mountains. So far, risk management has been developed by the Research Centre for Disasters Gadjah Mada University in collaboration with the Regional Development Planner (BAPPEDA), which carries out fundamental and applied researches. The results of the studies have been integrated in the risk prevention and landuse planning in order to improve the integrated landslide mitigation programme.  相似文献   

Preliminary identification of earthquake triggered multi-hazard and risk in Pleret Sub-District (Yogyakarta,Indonesia)     

Aditya Saputra  Christopher Gomez  Ioannis Delikostidis  Peyman Zawar-Reza  Danang Sri Hadmoko  Junun Sartohadi 《地球空间信息科学学报》2021,24(2):256-278

Yogyakarta is one of the large cities in Central Java, located on Java Island, Indonesia. The city, and the Pleret sub-district, where the study has taken place, is prone to earthquake hazards, because it is close to several seismically active zones, such as the Sunda Megathrust and the active fault known as the Opak Fault. Since a devastating earthquake of 2006, the population of the Pleret sub-district has increased significantly. Thus, the housing demand has increased, and so is the pace of low-cost housing that does not meet earthquake-safety requirements, and furthermore are often located on unstable slopes. The local alluvial material covering a jigsaw of unstable blocks and complex slope is conditions that can amplify the negative impacts of earthquakes. Within this context, this study is aiming to assess the multi-hazards and risks of earthquakes and related secondary hazards such as ground liquefaction, and coseismic landslides. To achieve this, we used geographic information systems and remote sensing methods supplemented with outcrop study and existing seismic data to derive shear-strain parameters. The results have revealed the presence of numerous uncharted active faults with movements visible from imagery and outcrops. show that the middle part of the study area has a complex geological structure, indicated by many unchartered faults in the outcrops. Using this newly mapped blocks combined with shear strain data, we reassessed the collapse probability of buildings that reach level >0.75 near the Opak River, in central Pleret sub-district. Classifying the buildings and from population distribution, we could determine that the highest risk was during nighttime as the buildings susceptible to fall are predominantly housing buildings. The secondary hazards follow a slightly different distribution with a concentration of risks in the West.  相似文献   

Natural hazards in Central Java Province,Indonesia: an overview   总被引：2，自引：0，他引：2  

Muh Aris Marfai  Lorenz King  Lalan Prasad Singh  Djati Mardiatno  Junun Sartohadi  Danang Sri Hadmoko  Anggraini Dewi 《Environmental Geology》2008,56(2):335-351

Central Java Province, Indonesia, suffers from natural hazard processes such as land subsidence, coastal inundation, flood, volcanic eruption, earthquake, tsunami, and landslide. The occurrence of each kind of natural hazard is varied according to the intensity of geo-processes. It is necessary to learn from the historical record of coastal inundation, flood, volcanic eruption, earthquake, tsunami, and landslide hazards in Central Java Province to address issues of comprehensive hazard mitigation and management action. Through the understanding about the nature and spatial distribution of natural hazards, treatments can be done to reduce the risks. This paper presents the natural hazard phenomena in Central Java Province and provides critical information for hazard mitigation and reduction.  相似文献   

Rockfall susceptibility zoning based on back analysis of rockfall deposit inventory in Gunung Kelir,Java     

Guruh Samodra  Guangqi Chen  Junun Sartohadi  Danang Sri Hadmoko  Kiyonobu Kasama  Muhammad Anggri Setiawan 《Landslides》2016,13(4):805-819

A rockfall susceptibility based on trajectory-energy/velocity approach needs release area or rockfall source. However, identification of rockfall source is not always possible for some areas in Indonesia. This paper presents a rockfall susceptibility zoning based on back analysis technique of rockfall deposit inventory in Gunung Kelir, Java. There were several steps in the rockfall susceptibility zoning: (1) rockfall deposit inventory, (2) rockfall simulation based on back analysis of rockfall deposit inventory, (3) sensitivity analysis, and (4) rockfall susceptibility zoning. The result suggests that the travel distance is affected by the spatial distribution of rockfall source, lithology or surface material, and topography (angle of slope and angle of aspect). Final trajectories were employed to generate landslide susceptibility map which may allow a policy maker to have an advanced consideration to achieve specified risk measures and evaluation of their cost efficiency to optimize budget and design. Application of rockfall susceptibility zoning based on back analysis of rockfall deposits is efficient where rockfall source information is unavailable.  相似文献