Monitoring of coastline change using Sentinel-2A and Landsat 8 data, a case study of Cam Pha city - Quang Ninh province

The main purpose of this study is to evaluate the performance of Sentinel - 2A and Landsat 8 data in monitoring coastline change from 1999 to 2018 at Cam Pha city, Quang Ninh province. Both data were collected under similar conditions of time and weather features to minimize the differences in interpretation results caused by these factors. The coastline was extracted from Sentinel-2A and Landsat 8 in 2018 by using the Normalized Difference Water Index (NDWI). Coastline map from Quang Ninh Department of Natural Resources and Environment with a scale of 1: 50.000 in 1999 was used as a reference of the same mask and overlaid on coastline maps in 2018 to identify the changes in the study area. The data from fieldwork and Google Earth was used to evaluate the accuracy and make comparative comments. The results presented that changes dramatically occurred between 1999 and 2018 with the accretion process prevailing. This process took place quite strongly on the East and Southeast coast while the erosion process only occurred with small areas at scattered points in the study area. The results also showed that the overall classification accuracy of Sentinel-2A imagery (95.0%) was slightly higher than that of Landsat-8 (87.5%). The combined use of Landsat-Sentinel-2 imagery is expected to generate reliable data records for continuous detecting of coastline changes.

Estimation of shear strength parameters of soil using Optimized Inference Intelligence System

In recent years, machine learning techniques have been developed and used to build intelligent information systems for solving problems in various fields. In this study, we have used Optimized Inference Intelligence System namely ANFIS-PSO which is a combination of Adaptive Neural-Fuzzy Inference System (ANFIS) and Particle Swarm Optimization (PSO) for the estimation of shear strength parameters of the soils (Cohesion “C” and angle of internal friction “φ”). These parameters are required for designing the foundation of civil engineering structures. Normally, shear parameters of soil are determined either in the field or in the laboratory which require time, expertise and equipments. Therefore, in this study, we have applied a hybrid model ANFIS-PSO for quick and cost-effective estimation of shear parameters of soil based on the other six physical parameters namely clay content, natural water content, specific gravity, void ratio, liquid limit and plastic limit. In the model study, we have used data of 1252 soft soil samples collected from the different highway project sites of Vietnam. The data was randomly divided into 70:30 ratios for the model training and testing, respectively. Standard statistical measures: Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and Correlation Coefficient (R) were used for the performance evaluation of the model. Results of the model study indicated that performance of the ANFIS-PSO model is very good in predicting shear parameters of the soil: cohesion (RMSE = 0.075, MAE = 0.041, and R = 0.831) and angle of internal friction (RMSE = 0.08, MAE = 0.058, and R = 0.952).

Relationship between seismicity and active faults in Thanh Hoa province detected by local seismic network

Thanh Hoa province belongs to the southwest part of Northwest Vietnam, which is considered a tectonically active region. In the area of Thanh Hoa province, there are three deep-seated tectonic faults, namely Son La-Bim Son, Song Ma, and Sop Cop. As predicted by scientists, these faults are capable of producing credible earthquakes that might be the strongest in the territory of Vietnam. Besides the three main seismogenic sources, in the province, there are other smaller active faults such as Thuong Xuan-Ba Thuoc and Thuong Xuan-Vinh Loc but the relationship of these faults with seismic activity is still rather blurred. This may due to the sparseness of the Vietnamese National Seismic Network which can not record adequately small earthquakes in the area. This paper presents new results of additional monitoring from a local seismic network using 12 Guralp - 6TD broadband seismometers that have been deployed in Thanh Hoa province since November 2009. We found that the Thanh Hoa area is not seismically quiet. The average number of earthquakes recorded by the network has reached 80 - 90 events per year and some of them have magnitude from ML 3.0 to 4.0.By integration of the earthquake epicenters derived from the local network and distribution of active faults, we can detect several earthquakes locating near the three active faults, not only along the main faults but also along its subsidiary faults. We focused on the active faults of Thuong Xuan-Ba Thuoc and Thuong Xuan-Vinh Loc by using the recent results of the gravity, seismic, and magnetotelluric data analyses. Several recorded earthquakes distribute along the two small faults and some of them reach magnitude 3.0 or greater on the ML scale. In this study, the Thuong Xuan-Vinh Loc is recognized as a seismogenic source. To identify seismic hazard potential caused by earthquakes generated from the active faults, segmentation of the Thuong Xuan - Ba Thuoc fault had been done based on geological and geomorphological indications and seismic activity, and then the peak ground acceleration was determined for each fault segment. Besides, a large number of earthquake epicenters do not have a good correlation with a specific fault, especially in the area of Thanh Hoa coastal plain, which is covered by thick layers of Neogene - Quaternary sediment. This shows that there may be hidden active faults in the area which are needed to study further.

Hydrogeology and origin of waters of the Panyam Volcanic Line springs, Jos Plateau, Nigeria

The PVL springs are used for both domestic and agricultural purposes. The seepage from the springs has resulted in producing a large expanse of wetlands and is therefore intensively use for dry season farming. The aim of this study was to determine the hydrogeological, hydrochemical characteristics, origin and their suitability for domestic and irrigation. The hydrogeology of the springs was determined by field mapping. The physico-chemical parameters were determined in the field and by laboratory methods. For the cation and anion analysis the ICP-MS and the wet methods were employed respectively. The stable isotope composition of oxygen (δ18O) and hydrogen (δ2H) were analyzed by Isotope Ratio Mass Spectrometer. The hydrochemical analysis revealed that the PVL springs waters are generally neutral with an average pH value of 7.3. The average TDS and EC values are 127.8mg/l and 246µs/cm respectively. These values fall within fresh water class. The average Mg2+,Ca2+, Na+ and K+ cation concentration values are 16.3mg/l, 15.8mg/l, 10.8mg/l and 5.58mg/l respectively. The average anions concentration of HCO3-, SO4 and Cl- are 140mg/l, 8.6mg/l and 3.4mg/l respectively. Piper trilinear diagram show that the spring waters is predominantly Mg-Ca-HCO3 water type with potable qualities based on WHO drinking water standards. The sodium Adsorption Ratio (SAR) and Sodium Soluble Percentage (SSP) values range between 0.44 to 0.84 and 26.4 to 54% respectively and falls within irrigation quality standards. Stable isotope compositions of δ18O and δ2H ranges from -3.60/00 to -4.90/00 and -200/00 to -280/00 respectively falls within the meteoric water composition. This is further affirmed by the δ2H versus δ18O plot on the correlation diagram with Standard Meteoric Water Line.

Paleomagnetism of Permian-Triassic volcanic sequences from Son La province, northwest Vietnam

Nineteen sites with 198 oriented-core samples have been collected from the Upper Permian-Lower Triassic volcanic rocks of Vien Nam Formation at Quynh Nhai locality, Son La Province, northwestern Vietnam. The characteristic remanent magnetization components carried by magnetite and hematite were successfully isolated from secondary components reveal a mean paleomagnetic direction Ds = 48.3°, Is = -10.0°, a95 = 8.0°, corresponding to a virtual geomagnetic pole located at l = 35.7°N, f = 217.4°E and a paleo-latitude of study area situated at 5.1°S during the Permian time. Compared with the Late Permian-Early Triassic pole of the South China Block (SCB), the data show that crustal elements of NW Vietnam have been close to, but not unequivocally a coherent part of the SCB, since the Late Permian. Development of the parallel NW-SE striking Song Ma and Song Chay orogenic belts did not involve the closure of wide (> 500 km) ocean basins.

NDSHA - The New Paradigm for RSHA - An Updated Review

A New Paradigm (data driven and not like the currently model driven) is needed for Reliable Seismic Hazard Assessment RSHA. Neo-Deterministic Seismic Hazard Assessment (NDSHA) integrates earthquake geology, earthquake science, and particularly earthquake physics to finally achieve a New (and needed) Paradigm for Reliable Seismic Hazard Assessment RSHA.Although observations from many recent destructive earthquakes have all confirmed the validity of NDSHA’s approach and application to earthquake hazard forecasting-nonetheless damaging earthquakes still cannot yet be predicted with a precision requirement consistent with issuing a red alert and evacuation order to protect civil populations. However, intermediate-term (time scale) and middle-range (space scale) predictions of main shocks above a pre-assigned threshold may be properly used for the implementation of low-key preventive safety actions, as recommended by UNESCO in 1997. Furthermore, a proper integration of both seismological and geodetic information has been shown to also reliably contribute to a reduction of the geographic extent of alarms and it therefore defines a New Paradigm for TimeDependent Hazard Scenarios: Intermediate-Term (time scale) and Narrow-Range (space scale) Earthquake Prediction.

Impact of the precise ephemeris on accuracy of GNSS baseline in relative positioning technique

For advanced geodesy tasks that require high-accuracy, such as tectonics, surveying services usually use not only long-baselines but also the duration of tracking GNSS satellites in a long (e.g., 24/7). The accuracy of these baselines in baseline analysis is dominated by inaccuracy satellite positioning and orbit, leading to specified accuracy may not be adequate. One way to overcome this problem is to use the final precise ephemeris, provided by IGS. The objective of this study is to investigate the impact of precise ephemeris on the accuracy of GNSS baselines in relative positioning techniques in two aspects: baseline length and duration of tracking GNSS satellites. To this end, 197 baselines were generated from a total of 88 CORS stations in South Korea, and then thirteen testing cases were constructed by grouping baseline lengths from under 10 km to over 150 km. Besides, data for one day of each CORS was divided into the different duration, such as 1, 2, 3, 6, and 24 hours. The GNSS measurements have been processed by TBC software with an application of the broadcast and precise ephemerides. The precision of the baseline processing from two types of ephemeris was analyzed about baseline lengths and time of data. The obtained results showed that using precise ephemeris significantly improved the accuracy of baseline solutions when the length of the baseline larger than 50km. In addition, this accuracy is independent of the length of baselines in the case of the precise ephemeris. Finally, the result of the testing baselines was enhanced when the duration of tracking data increases.

Finite element modeling of fluid flow in fractured porous media using unified approach

Understanding fluid flow in fractured porous media is of great importance in the fields of civil engineering in general or in soil science particular. This study is devoted to the development and validation of a numerical tool based on the use of the finite element method. To this aim, the problem of fluid flow in fractured porous media is considered as a problem of coupling free fluid and fluid flow in porous media or coupling of the Stokes and Darcy equations. The strong formulation of the problem is constructed, highlighting the condition at the free surface between the Stokes and Darcy regions, following by the variational formulation and numerical integration using the finite element method. Besides, the analytical solutions of the problem are constructed and compared with the numerical solutions given by the finite element approach. Both local properties and macroscopic responses of the two solutions are in excellent agreement, on condition that the porous media are sufficiently discretized by a certain level of finesse. The developed finite element tool of this study could pave the way to investigate many interesting flow problems in the field of soil science.

Removal of chromium from wastewater using paper waste sludge-derived hyrdrochar modified by naoh

In this work, paper waste sludge (PWS) collected from the primary settling tank of the paper wastewater treatment plant was utilized to generate hydrochar as a low-cost adsorbent for removal of Cr(VI) from aqueous solution. The characteristics of paper waste sludge hydrochar (PWSH) and the effects of adsorption conditions of Cr(VI) onto PWSH, including solution pH (3-9), contact time (5-240 min), initial Cr(VI) concentration (10-80 mg/L) and the adsorbent dose of 1 g/L at room temperature (25±2°C) were investigated. Adsorption isotherm and kinetics were also predicted in this work. The results indicate that the maximum adsorption capacity achieved 11.89 mg/g at 120 min of contact time, pH 3, and initial Cr(VI) concentration of 60 mg/L. The adsorption isotherm was reflected the best by the Langmuir model (R2 of 0.9968). Whereas, the adsorption kinetic also indicates that the pseudo-second-order model predicted the best for Cr(VI) adsorption process with a R2 of 0.9469. The mechanism of Cr(VI) adsorption process onto PWSH was chemical sorption through electrostatic interaction and ion exchange.

Petrographic and geochemical characteristics of the Nui Chua pegmatoid mafic-ultramafic series, Northern Vietnam: Significance in petrogenesis and Fe-Ti-V metallogenesis

The pegmatoid intrusions of the Nui Chua complex are one of the important mafic-ultramafic intrusive series associated with Fe-Ti-V ores in northern Vietnam. These intrusions consist of plagiowebsterite, clinopyroxenite, melanogabbronorite, mesogabbro, gabbronorite, and leucogabbronorite. The Fe-Ti oxide ores being massive or disseminated appear layered or veined in pegmatoid rocks. The geochemical characteristics of pegmatoid rocks are rich in Fe, Ti, V and poor Mg; their HREE are higher than LREE, with [La/Yb]N of 0.49 to 0.91 (average: 0.67), showing negative anomalies at Nb, Ta, Th, U, Sr, Zr and positive anomalies at Cs, Ti, and K. The chemical composition and distribution characteristics of trace and rare earth elements of mafic and ultramafic rocks show that they share the same magma source. Having the same geochemical tendency of intrusive formations, Fe-Ti oxide ores are magmatic origin associated with intrusive pegmatoid rocks. The pegmatoid rocks of the Nui Chua complex and Fe-Ti oxide ores are formed as a product of the fractional crystallization of Fe-Ti-rich residual melts after crystallization of the layered rocks.