Lunar glass compositions: Apollo 16 core sections 60002 and 60004     

Henry O.A. Meyer  Hsiao-Ming Tsai 《Earth and Planetary Science Letters》1975,28(2):234-240

Approximately 500 glasses between 1 mm and 125 μm in size have been analyzed from fourteen samples from the Apollo 16 core sections 60002 and 60004. The majority of glasses have compositions comparable to those found in previous studies of lunar surface soils; however, two new and distinct glass compositions that are probably derived in part from mare material occur in the core samples. The major glass composition in all samples is that of Highland Basalt glass, but it also appears that high-K Fra Mauro Basalt (KREEP) glass is more common at the Apollo 16 site than was previously thought. The relative abundance of glasses within the core samples is random in distribution: each sample is characterized by a particular assemblage and distribution of the constituent glass compositions.  相似文献   

Engineering Ground Motion Modeling in the Near-Source Regime Using the Specific Barrier Model for Probabilistic Seismic Hazard Analysis     

C.-C. P. Tsai 《Pure and Applied Geophysics》1998,152(1):107-123

—The specific barrier model is used for the first time to simulate ground motion accelerations for the purpose of probabilistic seismic hazard analyses at sites near a dominant fault system. It incorporates the simulation of fault geometry and the relationship between the stress drop and seismic moment to estimate the number of cracks on the fault for the specific barrier model. Radiated direct shear waves are established following Boore’s (1983) procedure. The simulated peak ground accelerations (PGA) are then calibrated by strong-motion data. Basically, the model is of uniform source, and the directivity of the source is not taken into consideration. The results show that the calibrated PGA values are not sensitive to the relationship between the stress drop and seismic moment. However, the calibrated PGA values may increase about 20 percent for sites near the fault when the cut-off frequency,?f _max?, is raised from 5 Hz to 10 Hz. The variability of the simulated ground motion is, in general, smaller than that of the empirical strong-motion data shown in the literature. This may be improved by adding randomness into the parameter of ?f _max and uncertainties into the empirical relationships adopted in the model. The simulated attenuation curves may be used to judge which types of conventional attenuation equations are better at representing the attenuation of PGA for sites near the fault, especially for large earthquake events.  相似文献   

Seven-day intensity and intensity spread predictions for western North Pacific tropical cyclones     

Hsiao-Chung Tsai  Russell L. Elsberry 《Asia-Pacific Journal of Atmospheric Sciences》2015,51(4):331-342

  相似文献   

Thermodynamic settings of melting and melt ascent from magmatic chambers using the example of Klyuchevskoi Volcano     

N. V. Chertkova  A. E. Tsai  N. L. Mironov  V. D. Shcherbakov 《Moscow University Geology Bulletin》2010,65(1):39-48

Theoretical models and experimental data on the thermodynamic and rheological properties of basalts from the Apakhonchich lava flow (Klyuchevskoi Volcano, Kamchatka) were invoked for plotting projections of water-containing and dry liquidus and solidus curves on the P _s -T plane. The P-T-X _{H 2O} conditions for the formation of basaltic magma and the degree of its differentiation were determined from data on melt inclusions. The calculated apparent viscosity of the melt containing 10% crystals at 1100°C, 1 GPa, and 3 wt % water is 1.1 × 10³ Pa s, and the density is 2.5 g/cm³.  相似文献   

Effects of degree of saturation on shallow landslides triggered by rainfall   总被引：4，自引：3，他引：1  

Tung-Lin Tsai  Hsin-Fa Chen 《Environmental Earth Sciences》2010,59(6):1285-1295

The empirical rainfall threshold concept and the physical-based model are two commonly used approaches for the assessment of shallow landslides triggered by rainfall. To investigate in detail the rainfall-triggered shallow landslides, many physical-based models coupling the infinite slope stability analysis with the rainfall infiltration modeling in variably saturated soil were developed. However, in those physical-based shallow landslide models, the unit weight and the unsaturated shear strength were assumed constant rather than depending on the degree of saturation. In this study, the effects of the unit weight and the unsaturated shear strength as function of degree of saturation on rainfall-triggered shallow landslides are examined. Several designed scenarios and a real case scenario are used to conduct the examinations. The results show that not only the occurrence of shallow landslides but also the failure depth and the time to failure could be misassessed if the influences of degree of saturation on the unit weight and the unsaturated shear strength are neglected.  相似文献   

Applications of situation-dependent intensity and intensity spread predictions based on a weighted analog technique     

Hsiao-Chung Tsai  Russell L. Elsberry 《Asia-Pacific Journal of Atmospheric Sciences》2014,50(4):507-518

A version of our situation-dependent intensity prediction (SDIP) is proposed for operational application after three modifications: (i) Ten historical track analogs are matched with Joint Typhoon Warning Center (JTWC) official track forecasts rather than besttracks; (ii) Giving two times as much weight to the 72 h — 120 h portion of the track as to the 0–72 h portion to give higher rankings for analog tracks with similar landfall or recurvature positions and timing; and (iii) Weighting both the intensity prediction technique and a new intensity spread guidance product according to new rankings of the track analogs rather than assuming all track analogs are equally likely. These special matchings and weightings of the track analogs in this weighted-analog intensity (WANI) add skill in the 72–120 h forecast intervals in regions where landfalls occur. Viability as an operational technique is demonstrated as the WANI has only 1 kt larger mean absolute errors than the JTWC intensity errors from 12 h through 72 h, and the WANI is 5 kt (20%) better at 120 h. The WANI rank-weighted intensity spreads each 12 h among the 10 best historical track analogs are processed to reduce any intensity bias and calibrated to reduce (increase) the over-determined (under-determined) intensity spreads at early (later) forecast intervals. Thus, the situation-dependent intensity spread guidance is generated that will include about 68% of the verifying intensities at all forecast intervals. Four examples of the WANI intensity predictions and intensity spread guidance are presented to illustrate how the forecaster might use this information in potential landfall and intensity bifurcation situations.  相似文献   

Spatial distribution of soil erosion and suspended sediment transport rate for Chou-Shui river basin     

Chin-Ping Lin  Ching-Nuo Chen  Yu-Min Wang  Chih-Heng Tsai  Chang-Tai Tsai 《Journal of Earth System Science》2014,123(7):1517-1539

In this study, a Physiographic Soil Erosion–Deposition Model (PSED) is applied for better management of a watershed. The PSED model can effectively evaluate the key parameters of watershed management: surface runoff discharge, suspended sediment transport rate, quantity of soil erosion, and spatial distribution of soil erosion and deposition. A basin usually contains multiple watersheds. These watersheds may have complex topography and heterogeneous physiographic properties. The PSED model, containing a physiographic rainfall-runoff model and a basin scale erosion–deposition model, can simulate the physical mechanism of the entire erosion process based on a detailed calculation of bed-load transportation, surface soil entrainment, and the deposition mechanism. With the assistance of Geographic Information Systems (GIS), the PSED model can handle and analyze extremely large hydrologic and physiographic datasets and simulate the physical erosion process without the need for simplification. We verified the PSED model using three typhoon events and 40 rainfall events. The application of PSED to Chou-Shui River basin shows that the PSED model can accurately estimate discharge hydrographs, suspended sediment transport rates, and sediment yield. Additionally, we obtained reasonable quantities of soil erosion as well as the spatial distribution of soil erosion and deposition. The results show that the PSED model is capable of calculating spatially distributed soil erosion and suspended sediment transport rates for a basin with multiple watersheds even if these watersheds have complex topography and heterogeneous physiographic properties.  相似文献   

Biodegradation and transport of benzene,toluene, and xylenes in a simulated aquifer: comparison of modelled and experimental results     

Jiin‐Shuh Jean  Ching‐Lang Tsai  Shen‐Haw Ju  Chun‐Wen Tsao  Shih‐Ming Wang 《水文研究》2002,16(16):3151-3168

Both laboratory experiments and numerical modelling were conducted to study the biodegradation and transport of benzene–toluene–xylenes (BTX) in a simulated semi‐confined aquifer. The factors incorporated into the numerical model include advection, hydrodynamic dispersion, adsorption, and biodegradation. The various physico‐chemical parameters required by the numerical model were measured experimentally. In the experimental portion of the study, BTX compounds were introduced into the aquifer sand. After the contaminants had been transported through the system, BTX concentrations were measured at 12 equally spaced wells. Subsequently, microorganisms obtained from the activated sludge of a sewage treatment plant and cultured in BTX mixtures were introduced into the aquifer through the 12 sampling wells. The distribution data for BTX adsorption by the aquifer sand form a nonlinear isotherm. The degree of adsorption by the sand varies, depending on the composition of the solute. The degradation time, measured from the time since the bacteria were added to the aquifer until a specific contaminant was no longer detectable, was 35–42 h for BTX. The dissolved oxygen, after degradation by BTX compounds and bacteria, was consumed by about 40–60% in the entire simulated aquifer; thus the aerobic conditions were maintained. This study provides insights for the biodegradation and transport of BTX in aquifers by numerical modelling and laboratory experiments. Experimental and numerical comparisons indicate that the results by Monod degradation kinetics are more accurate than those by the first‐order degradation kinetics. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Aquifer Characterization Using Fiber Bragg Grating Multi-Level Monitoring System     

Yu-Li Wang  Liang-Cheng Chang  Fei Liu  Yen-Te Ho  Tzu Bin Wang  Tian-Chyi Jim Yeh  Jui-Pin Tsai 《Ground water》2022,60(4):518-529

Groundwater responses measured from multiple wells at different depths are essential for delineating the aquifer heterogeneity using hydraulic tomography (HT). In general, conducting HT requires many wells because traditional well monitoring is usually partially open at a specific depth interval or is fully penetrating. Accordingly, conducting an HT survey is typically costly and time-consuming. To tackle these issues, a new multi-level monitoring system (MLMS) for the HT survey was developed using the fiber Bragg grating (FBG) technique. This FBG MLMS could collect the depth-discrete groundwater observations from a fully penetrated 2-inch well. Three field campaigns were conducted to validate the capability of the FBG MLMS for HT surveys. The results show that the accuracy and stability of this MLMS are reliable and that FBG MLMS is beneficial for conducting an HT survey. Specifically, compared to the traditional monitoring well in an injection event, this FBG MLMS can concurrently cause an increase in the number of cross-hole tests several times and collect many more head observations than the standard methods, resulting in the observed flow fields efficiently reaching ergodic conditions and effectively improving the accuracy of the estimated hydraulic heterogeneity. Therefore, the FBG MLMS could be an alternative MLMS for efficiently and economically conducting an HT survey.  相似文献   

Comparative study of climate-change scenarios on groundwater recharge,southwestern Mississippi and southeastern Louisiana,USA     

Ehsan Beigi  Frank T.-C. Tsai 《Hydrogeology Journal》2015,23(4):789-806

  相似文献