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1.
Rio Raharja Endra Gunawan Irwan Meilano Hasanuddin Z. Abidin Joni Efendi 《地震科学（英文版）》2016,29(5):291-298
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. 相似文献
2.
Hasanuddin Z. Abidin I. Gumilar H. Andreas D. Murdohardono Y. Fukuda 《Environmental Earth Sciences》2013,68(6):1545-1553
The Bandung Basin is a large intra-montane basin surrounded by volcanic highlands, in western Java, Indonesia, inhabited by more than seven million people. The basin, an area of about 2,300 km2, is a highland plateau at approximately 650–700 m above sea level and is surrounded by up to 2,400 m high Late Tertiary and Quaternary volcanic terrain. Based on the results of nine GPS surveys conducted since 2000 up to 2011, it was shown that several locations in the Bandung Basin have experienced land subsidence, with an average rate of about ?8 cm/year and can go up to about ?23 cm/year in certain locations. A hypothesis has been proposed by several studies that land subsidence observed in several locations in the Bandung Basin has been caused mainly by excessive groundwater extraction. It is found that there is a strong correlation between the rates of groundwater level lowering with the GPS-derived rates of land subsidence in several locations in Bandung Basin. The GPS results in this study detected significant subsidence in the textile industry area, where very large volumes of groundwater are usually extracted. The impact of land subsidence in Bandung can be seen in several forms, mainly in the cracking and damage of houses, buildings and infrastructure. Land subsidence also aggravates the flooding in Bandung Basin, which has brought huge economic losses and deteriorated the quality of life and environment in the affected areas. 相似文献
3.
Hasanuddin Z. Abidin H. Andreas M. Gamal Ony K. Suganda Irwan Meilano M. Hendrasto M. A. Kusuma D. Darmawan M. A. Purbawinata A. D. Wirakusumah F. Kimata 《GPS Solutions》2006,10(2):75-84
Papandayan is an A-type active volcano located in the southern part of Garut Regency, about 70 km southeast of Bandung, Indonesia. Its earliest recorded eruption, and the most violent and devastating outburst, occurred in 1772. The latest eruptions occurred in the period from 11 November–8 December 2002, and consisted of phreatic, freatomagmatic, and magmatic types of eruption. During the latest eruption period, GPS surveys were conducted at several points inside and around the crater in a radial mode, using the reference point located at the Papandayan observatory, about 10 km from the crater. At the points closest to the erupting craters, GPS displacements up to a few decimeters were detected, whereas at the points outside the crater, the displacements were at the centimeter level. The magnitude of displacements observed at each point also showed a temporal variation according to the eruption characteristics. The results show that deformation during eruption tends to be local, e.g. just around the crater. The pressure source is difficult to be properly modeled from GPS results, due to the limited GPS data available and differences in topography, geological structure, and/or rheology related to each GPS station. 相似文献
4.
Identifying groundwater arsenic contamination mechanisms in relation to arsenic concentrations in water and host rocks 总被引：1，自引：1，他引：0
Leaching and oxidation of high arsenic (As) host rocks tend to be induced by circulation of deep geothermal waters, which
increase As concentration in shallow groundwater. The purpose of this study is to identify the mechanism of groundwater As
contamination in relation to leaching and oxidation along the border between the South Minahasa and Bolaang Mongondow districts,
North Sulawesi, Indonesia. This region contains Miocene sedimentary rock-hosted disseminated gold deposits associated with
hydrothermal alteration in a fault zone. Abnormally high As concentrations were observed in hot and cold springs and in surrounding
shallow groundwater for a total mineralization area of 8 × 10 km2. Two methods were adopted in this study: (1) microscopic and spectroscopic analyses of rock samples for mineral identification
and (2) geostatistics for spatial modeling of As concentrations in groundwater. Jarosite was identified as the chief fill
mineral in rock defects (cracks and pores). The presence of this mineral may indicate release of As into the environment,
as can occur as an alteration product derived from oxidation and leaching of pyrite, As-rich pyrite or sulfide minerals by
geothermal waters. Moreover, As concentrations in groundwater were estimated using geostatistics for spatial modeling. The
co-kriging map identified local anomalies in groundwater As concentrations over the permissible limit (10 ppb). Such anomalies
did not appear through ordinary kriging. Integration of the results indicates that As contamination in shallow groundwater
probably is controlled by heterogeneous distributions of jarosite and variations in intensity and extent of hydrothermal activities. 相似文献
5.
Hasanuddin Z. Abidin Heri Andreas Irwan Gumilar Yoichi Fukuda Yusuf E. Pohan T. Deguchi 《Natural Hazards》2011,59(3):1753-1771
Jakarta is the capital city of Indonesia with a population of about 9.6 million people, inhabiting an area of about 660 square-km.
In the last three decades, urban development of Jakarta has grown very rapidly in the sectors of industry, trade, transportation,
real estate, and many others. This exponentially increased urban development introduces several environmental problems. Land
subsidence is one of them. The resulted land subsidence will also then affect the urban development plan and process. It has
been reported for many years that several places in Jakarta are subsiding at different rates. The leveling surveys, GPS survey
methods, and InSAR measurements have been used to study land subsidence in Jakarta, over the period of 1982–2010. In general,
it was found that the land subsidence exhibits spatial and temporal variations, with the rates of about 1–15 cm/year. A few
locations can have the subsidence rates up to about 20–28 cm/year. There are four different types of land subsidence that
can be expected to occur in the Jakarta basin, namely: subsidence due to groundwater extraction, subsidence induced by the
load of constructions (i.e., settlement of high compressibility soil), subsidence caused by natural consolidation of alluvial
soil, and tectonic subsidence. It was found that the spatial and temporal variations of land subsidence depend on the corresponding
variations of groundwater extraction, coupled with the characteristics of sedimentary layers and building loads above it.
In general, there is strong relation between land subsidence and urban development activities in Jakarta. 相似文献
6.
Frederick T. Short Robert Coles Miguel D. Fortes Steven Victor Maxwell Salik Irwan Isnain Jay Andrew Aganto Seno 《Marine pollution bulletin》2014
Seagrass systems of the Western Pacific region are biodiverse habitats, providing vital services to ecosystems and humans over a vast geographic range. SeagrassNet is a worldwide monitoring program that collects data on seagrass habitats, including the ten locations across the Western Pacific reported here where change at various scales was rapidly detected. Three sites remote from human influence were stable. Seagrasses declined largely due to increased nutrient loading (4 sites) and increased sedimentation (3 sites), the two most common stressors of seagrass worldwide. Two sites experienced near-total loss from of excess sedimentation, followed by partial recovery once sedimentation was reduced. Species shifts were observed at every site with recovering sites colonized by pioneer species. Regulation of watersheds is essential if marine protected areas are to preserve seagrass meadows. Seagrasses in the Western Pacific experience stress due to human impacts despite the vastness of the ocean area and low development pressures. 相似文献
7.
8.
Lilik Eko Widodo Tedy Agung Cahyadi Zuher Syihab Sudarto Notosiswoyo Irwan Iskandar Heru Cahya Rustamaji 《Environmental Earth Sciences》2018,77(20):721
High rainfall in equatorial regions leads to high groundwater levels or pore pressures and a high risk of landslides on the slopes of open pit mines, hindering mining operations. To lower the groundwater level surrounding a slope, a drainage system is needed. A drain hole is a part of a drainage system which utilises gravity to drain groundwater. Drain hole installation in fractured media requires the determination of the number, location, length and other parameters of the drain holes. Drain holes are frequently installed in uniform configurations or in layouts with uniform spacing, which are often ineffective and uneconomical, as some holes are not in the right positions or directions within the fractured media. This paper attempts to develop a conceptual model of an optimised configuration of drain holes by setting the drain hole parameters, or decision variables, such as number, location and length, in such a way that it produces the most effective and efficient outcome by maximising groundwater lowering and minimising cost. The optimisation is supported by the multi-stage genetic algorithm method in combination with a groundwater simulator, hereafter called the multi-stage GWSim-GA SO method. The procedure of the conceptual model will be further developed and used as a framework in the groundwater management of fractured media of an open pit mine slope. 相似文献
9.
Distinguishing potential sources of arsenic released to groundwater around a fault zone containing a mine site 总被引：1，自引：1，他引：0
Arsenic (As) contamination in groundwater in mineralized areas typically results from the oxidation of As-rich sulfide minerals in aquifers, from hydrothermal alteration of geothermal systems, or as a result of anthropogenic influences such as mining activity. The primary goal of this study was to determine the spatial and temporal variance in As concentrations in shallow groundwater in a mineralized area and to identify the main As source controlling the concentration patterns. To this end, a combination of a geostatistical technique for space–time modeling of As concentrations and a numerical simulation, which models the transport of As in groundwater, is implemented. A study site in North Sulawesi, Sulawesi Island, Indonesia was selected as it was suitable for investigating the importance of fault lines and metal mining on As contamination. Initially, stable isotope analysis was used to ascertain the groundwater source and the mixing mechanism of the shallow and deep groundwater. Geostatistical modeling revealed consistent general patterns of As concentrations during the past 10 years, with high concentrations found along a NW–SE axis. By matching the geostatistical results with the distributions of As concentrations obtained through transport modeling, the deep-seated hydrothermal system along the fault zone was found to be the major As source. Wastewater from the mine was also observed to be a local As source. Another important influence on the As concentration pattern was a river, which acted as a boundary to separate the groundwater systems into two regions. 相似文献
10.
Widodo Lilik E. Prassetyo Simon H. Simangunsong Ganda M. Iskandar Irwan 《Hydrogeology Journal》2022,30(6):1877-1898
Soil liquefaction on 28 September 2018 in Palu, Indonesia, included one of the largest soil movements ever, where objects on the ground surface moved hundreds of meters away and settlements sank into the mud. Some preliminary studies show that in addition to a strong earthquake, there are strong indications that a confined aquifer in the Palu valley worsened the liquefaction. The role of the confined aquifer can be recognized early on from one of various signs, namely the presence of massive surface inundations suspected due to groundwater expulsion which is thought to originate mostly from the confined aquifer. This paper describes the mechanism of the soil liquefaction in Palu from the perspective of earthquake hydrogeology, focusing on the groundwater expelled from an unconfined aquifer and especially from the underlying confined aquifer through hydraulic inter-connection between the two, which is possible due to simultaneous interaction of excess pore pressure dissipation and enhanced permeability driven by an earthquake in the near field. If this hypothesis proves to be strong, there are implications for engineering practices because the evaluation of potential soil liquefaction carried out currently in the geotechnical engineering field generally only involves the role of shallow groundwater and/or the unconfined aquifer and the role of soil layers not deeper than 30 m from the ground surface. It may be necessary to complement current evaluation practice with an evaluation of the deep groundwater response to earthquakes, especially if the deep groundwater is artesian and productive, with a relatively thin confining layer.
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