Subsidence in the Kathmandu Basin,before and after the 2015 Mw 7.8 Gorkha Earthquake,Nepal Revealed from Small Baseline Subset-DInSAR Analysis     

Suresh Krishnan P.V.  Jungkyo Jung 《地理信息系统科学与遥感》2018,55(4):604-621

Land subsidence in densely urbanized areas is a global problem that is primarily caused by excessive groundwater withdrawal. The Kathmandu Basin is one such area where subsidence due to groundwater depletion has been a major problem in recent years. Moreover, on 25 April 2015, this basin experienced large crustal movements caused by the Gorkha earthquake (Mw 7.8). Consequently, the effects of earthquake-induced deformation could affect the temporal and spatial nature of anthropogenic subsidence in the basin. However, this effect has not yet been fully studied. In this paper, we applied the SBAS-DInSAR technique to estimate the spatiotemporal displacement of land subsidence in the Kathmandu Basin before and after the Gorkha earthquake, using 16 ALOS-1 Phased Array L-band Synthetic Aperture Radar (PALSAR) images during the pre-seismic period and 26 Sentinel-1 A/B SAR images during the pre- and post-seismic periods. The results showed that the mean subsidence rate in the central part of the basin was about ?8.2 cm/year before the earthquake. The spatial extents of the subsiding areas were well-correlated with the spatial distributions of the compressible clay layers in the basin. We infer from time-series InSAR analysis that subsidence in the Kathmandu basin could be associated with fluvio-lacustrine (clay) deposits and local hydrogeological conditions. However, after the mainshock, the subsidence rate significantly increased to ?15 and ?12 cm/year during early post-seismic (108 days) and post-seismic (2015–2016) period, respectively. Based on a spatial analysis of the subsidence rate map, the entire basin uplifted during the co-seismic period has started to subside and become stable during the early-post-seismic period. This is because of the elastic rebound of co-seismic deformation. However, interestingly, the localized areas show increased subsidence rates during both the early-post- and post-seismic periods. Therefore, we believe that the large co-seismic deformation experienced in this basin might induce the local subsidence to increase in rate, caused by oscillations of the water table level in the clay layer.  相似文献   

Day-Night and Gastrointestinal Changes in Winter Feeding Intensity and Prey Composition of Apogon lineatus Inhabiting the Southeastern Waters of Korea     

Park  Joo Myun  Jung  Hae Kun  Lee  Chung Il  Huh  Sung-Hoi 《Ocean Science Journal》2019,54(1):141-146

Ocean Science Journal - Diel and gastrointestinal changes in relation to the feeding intensity and prey composition of Apogon lineatus were investigated through the analysis of the diet contents of...  相似文献   

Assessment of future runoff trends under multiple climate change scenarios in the Willamette River Basin,Oregon, USA     

Il‐Won Jung  Heejun Chang 《水文研究》2011,25(2):258-277

We investigated trends in future seasonal runoff components in the Willamette River Basin (WRB) of Oregon for the twenty‐first century. Statistically downscaled climate projections by Climate Impacts Group (CIG), eight different global climate model (GCM) simulations with two different greenhouse gas (GHG) emission scenarios, (A1B and B1), were used as inputs for the US Geological Survey's Precipitation Runoff Modelling System. Ensemble mean results show negative trends in spring (March, April and May) and summer (June, July and August) runoff and positive trends in fall (September, October and November) and winter (December, January and February) runoff for 2000–2099. This is a result of temperature controls on the snowpack and declining summer and increasing winter precipitation. With temperature increases throughout the basin, snow water equivalent (SWE) is projected to decline consistently for all seasons. The decreases in the centre of timing and 7‐day low flows and increases in the top 5% flow are caused by the earlier snowmelt in spring, decreases in summer runoff and increases in fall and winter runoff, respectively. Winter runoff changes are more pronounced in higher elevations than in low elevations in winter. Seasonal runoff trends are associated with the complex interactions of climatic and topographic variables. While SWE is the most important explanatory variable for spring and winter runoff trends, precipitation has the strongest influence on fall runoff. Spatial error regression models that incorporate spatial dependence better explain the variations of runoff trends than ordinary least‐squares (OLS) multiple regression models. Our results show that long‐term trends of water balance components in the WRB could be highly affected by anthropogenic climate change, but the direction and magnitude of such changes are highly dependent on the interactions between climate change and land surface hydrology. This suggests a need for spatially explicit adaptive water resource management within the WRB under climate change. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Including spatial distribution in a data‐driven rainfall‐runoff model to improve reservoir inflow forecasting in Taiwan          下载免费PDF全文

Meng‐Jung Tsai  Robert J. Abrahart  Nick J. Mount  Fi‐John Chang 《水文研究》2014,28(3):1055-1070

Multi‐step ahead inflow forecasting has a critical role to play in reservoir operation and management in Taiwan during typhoons as statutory legislation requires a minimum of 3‐h warning to be issued before any reservoir releases are made. However, the complex spatial and temporal heterogeneity of typhoon rainfall, coupled with a remote and mountainous physiographic context, makes the development of real‐time rainfall‐runoff models that can accurately predict reservoir inflow several hours ahead of time challenging. Consequently, there is an urgent, operational requirement for models that can enhance reservoir inflow prediction at forecast horizons of more than 3 h. In this paper, we develop a novel semi‐distributed, data‐driven, rainfall‐runoff model for the Shihmen catchment, north Taiwan. A suite of Adaptive Network‐based Fuzzy Inference System solutions is created using various combinations of autoregressive, spatially lumped radar and point‐based rain gauge predictors. Different levels of spatially aggregated radar‐derived rainfall data are used to generate 4, 8 and 12 sub‐catchment input drivers. In general, the semi‐distributed radar rainfall models outperform their less complex counterparts in predictions of reservoir inflow at lead times greater than 3 h. Performance is found to be optimal when spatial aggregation is restricted to four sub‐catchments, with up to 30% improvements in the performance over lumped and point‐based models being evident at 5‐h lead times. The potential benefits of applying semi‐distributed, data‐driven models in reservoir inflow modelling specifically, and hydrological modelling more generally, are thus demonstrated. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Why the twenty-first century tropical Pacific trend pattern cannot significantly influence ENSO amplitude?     

Soon-Il An  Jung Choi 《Climate Dynamics》2015,44(1-2):133-146

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Evaluation of Hydraulic Properties of Aquitards Using Earthquake‐Triggered Groundwater Variation          下载免费PDF全文

Shih‐Jung Wang  Kuo‐Chin Hsu  Chein‐Lee Wang  Wen‐Chi Lai  Liang‐Tzu Hsu 《Ground water》2017,55(5):747-756

The hydraulic properties of aquitards are not easily obtained because monitoring wells are usually installed in aquifers for groundwater resources management. Earthquake‐induced crust stress (strain) triggers groundwater level variations over a short period of time in a large area. These groundwater anomalies can be used to investigate aquifer systems. This study uses a poroelastic model to fit the postseismic variations of groundwater level triggered by the Chi‐Chi earthquake to evaluate the hydraulic properties of aquitards in the Jhoushuei River alluvial fan (JRAF), Taiwan. Six of the adopted eight wells with depths of 70 to 130 m showed good agreement with the recovery theory. The mean hydraulic conductivities (K) of the aquifers for the eight wells are 1.62 × 10^?4 to 9.06 × 10^?4 m/s, and the thicknesses are 18.8 to 46.1 m. The thicknesses of the aquitards are 11.3 to 42.0 m. Under the isotropic assumption for K, the estimated values of K for the aquitards are 3.0 × 10^?8 to 2.1 × 10^?6 m/s, corresponding to a silty medium. The results match the values obtained for the geological material of the drilling core and those reported in previous studies. The estimated values were combined with those given in previous studies to determine the distribution of K in the first two aquitards in the JRAF. The distribution patterns of the aquitards reflect the sedimentary environments and fit the geological material. The proposed technique can be used to evaluate the K value of aquitards using inverse methods. The inversion results can be used in hydrogeological analyses, contaminant modeling, and subsidence evaluation.  相似文献   

A biogeochemical orientation survey in the Moisan gold-mineralized area, Haenam district in Korea     

Ji-Eun Jung  Jong-Nam Kim  Hyo-Taek Chon 《Journal of Geochemical Exploration》2011,111(3):152-159

A biogeochemical orientation survey was carried out in the vicinity of an epithermal Au deposit in the Moisan Au–Ag mineralized area, Haenam district in Korea. The Au–Ag bearing quartz veins of the mine occur as narrow open-space fillings within Cretaceous silicic pyroclastics. The vein minerals consist mainly of quartz, sericite, pyrite, chalcopyrite, and galena, with some electrum and argentite. The main objectives of this study were to study the geochemical characteristics of rocks, soils and plants in this area, to investigate the spatial relationship between Au and associated elements in rock–soil–plant system, and to evaluate the applicability of biogeochemical prospecting for Au vein occurrences in Korea. Samples of rocks and soils, and leaves of three plant species (Japanese red pine — P. densiflora, oriental white oak — Q. aliena, Japanese mallotus — M. japonicus) were collected from the target mineralized area and control barren locations, and analyzed for trace elements by instrumental neutron activation analysis. Sampling lines were composed of one slope line which is almost parallel to the mineralized quartz-veins, and four transect lines spaced 100 m apart across the veins at 20 m sampling intervals. From the multi-element data of rock samples (n = 9), high values of Au (maximum 2030 ppb) are spatially related to Au–quartz veins. Soil samples (n = 61) collected from five sampling lines show higher values of Au (24–825 ppb) whereas soil samples from the control locations have lower values of Au (below 25 ppb). Many plant species collected from the vicinity of the veins have high Au contents compared with those at the control locations, but the ranges of Au values are variable among plant species. In a total of 128 samples of plant leaves, Q. aliena yielded Au values of 0.4 to 6.9 ppb, and M. japonicus 0.9 to 4.1 ppb. Gold contents in P. densiflora ranged from 0.1 to 5.6 ppb. Plant leaves from control areas show less than 1.6 ppb Au. The biological absorption coefficient (BAC) of Au in plants decreases in the order of Q. aliena > M. japonicus > P. densiflora. Based on the results of the study, Q. aliena appeared to be the best sampling media for biogeochemical prospecting of Au in the study area.  相似文献   

The logistics of household hurricane evacuation   总被引：1，自引：1，他引：0  

Michael K. Lindell  Jung Eun Kang  Carla S. Prater 《Natural Hazards》2011,58(3):1093-1109

Although there is a substantial amount of research on households’ hurricane evacuation decision making, there is much less research on the logistical issues involved in implementing those evacuations. The limited research on household evacuation logistics has consistently shown that most evacuees stay in the homes of friends and relatives or in commercial facilities rather than in public shelters. However, evacuation logistics—which can be defined as the activities and associated resources needed to reach a safe location and remain there until it is safe to return—encompasses a much broader range of behaviors than this. The present study extends previous research by reporting data on other aspects of evacuation logistics such as departure timing, vehicle use, evacuation routes, travel distance, shelter type, evacuation duration, and evacuation cost. Hurricane Lili evacuation data at the county level are generally consistent with the data from previous hurricanes, but there is notable variation across counties studied here. There were only modest correlations of demographic and geographic variables with the evacuation logistics variables, a result that indicates further research is needed to better understand what happens between the time an evacuation decision is made and the time re-entry is begun. Moreover, research is needed to understand the logistics of evacuation by special populations such as transients and households with disabled members.  相似文献   

Modeling and control of a 75 kW class variable liquid-column oscillator for highly efficient wave energy converter     

Byung-Hak Cho  Dong-Soon Yang  Shin-Yeol Park  Kyung-Shik Choi  Do-Hwan Lee  Seung-Hyun Byun  Hoon Jung 《Ocean Engineering》2011,38(2-3):436-443

The modeling and control of a variable liquid-column oscillator having a liquid filled U-tube with air chambers at its vertical columns are presented. As an ocean wave energy extracting device, the structure of the variable liquid-column oscillator (VLCO) is analogous to that of the tuned liquid-column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. However, owing to an air spring effect caused by the dynamic pressure of air chambers, the amplitude of response of the VLCO becomes significantly amplified for a desired wave period. The governing equations for the motion of VLCO structure under wave excitation and the motion of liquid with an air spring effect caused by an air–liquid interaction are described by a series of nonlinear differential equations. A set of control parameters for extracting maximum power from various wave conditions is determined for the efficient operation of the VLCO. It is found that the effect of the air spring has an important role to play in making the oscillation of the VLCO match with the ocean wave. In this way, the VLCO provides the most effective mode for extracting energy from the ocean wave.  相似文献   

Classification of precipitation types using fall velocity-diameter relationships from 2D-video distrometer measurements     

Jeong-Eun Lee  Sung-Hwa Jung  Hong-Mok Park  Soohyun Kwon  Pay-Liam Lin  GyuWon Lee 《大气科学进展》2015,32(9):1277-1290

Fall velocity-diameter relationships for four different snowflake types (dendrite, plate, needle, and graupel) were investigated in northeastern South Korea, and a new algorithm for classifying hydrometeors is proposed for distrometric measurements based on the new relationships. Falling ice crystals (approximately 40 000 particles) were measured with a two-dimensional video disdrometer (2DVD) during a winter experiment from 15 January to 9 April 2010. The fall velocity-diameter relationships were derived for the four types of snowflakes based on manual classification by experts using snow photos and 2DVD measurements: the coefficients (exponents) for different snowflake types were 0.82 (0.24) for dendrite, 0.74 (0.35) for plate, 1.03 (0.71) for needle, and 1.30 (0.94) for graupel, respectively. These new relationships established in the present study (PS) were compared with those from two previous studies. Hydrometeor types were classified with the derived fall velocity-diameter relationships, and the classification algorithm was evaluated using 3× 3 contingency tables for one rain-snow transition event and three snowfall events. The algorithm showed good performance for the transition event: the critical success indices (CSIs) were 0.89, 0.61 and 0.71 for snow, wet-snow and rain, respectively. For snow events, the algorithm performance for dendrite and plate (CSIs = 1.0 and 1.0, respectively) was better than for needle and graupel (CSIs = 0.67 and 0.50, respectively).  相似文献