Methods for constructing VS30 maps from geology, borehole and topography data

The average shear wave velocity in the upper 30 meters of a soil profile (VS30) is used in building codes to separate sites into classes for the purpose of earthquake engineering design. In this paper, a method of Thompson E.N. and Wald D.J. (2012) was applied to build a VS30 map of Ho Chi Minh city using, many different data such as geologic, topographic and shear wave velocities derived from the Standard Penetration Test (SPT) data of 104 boreholes. The VS30 values are mainly within two ranges of 0 -180 m/s and 180 - 240 m/s corresponding to two site classes of type D and C, respectively, according to the soil classification in Vietnam Construction Code TCVN 9386:2012. The site class of type C is mainly distributed in the districts located in the northern area of Ho Chi Minh city, while the soft soil with VS30 180 m/s is concentrated in the south of the city. This result shows that this method can reduce the uncertainty of VS30 map by up to 11.4% relative to the topography slope-only approach. Moreover, the average topographic slope of Ho Chi Minh city area is about 0.0024. It implies that Ho Chi Minh city area is in a stable continental region, which is suitable to apply ground motion prediction equations developed for seismic stable regions for the purpose of seismic hazard assessment. Our study is a prerequisite for the wide application of this method to build VS30 maps for other areas in Vietnam.ReferencesAbrahamson, N., Atkinson, G., Boore, D.M., Bozorgnia, Y, Campbell, K., Chiou, B., Idriss, I.M., Silva, W., and Youngs, R., 2008. Comparisons of the NGA ground-motion relations. Earthquake Spectra 24(1), 45-66.Allen, T. I. and Wald D. J., 2009. On the Use of High-Resolution Topographic Data as a Proxy for Seismic Site Conditions (VS30). Bull. Seism. Soc. Am., 99(2A), 935-943.Borcherdt, R. D., 1994. Estimates of site-dependent response spectra for design (methodology and justification). Earthquake Spectra 10, 617-654.Bozorgnia, Y., N. A. Abrahamson, L. Al Atik, T. D. Ancheta, G. M. Atkinson, J. W. Baker, A. Baltay, D. M. Boore, K. W. Campbell, B. S.-J. Chiou, et al., 2014. NGA-West2 research project, Earthquake Spectra, 30(3), 973-987.Bui Thi Nhung and Nguyen Hong Phuong, 2015. Local site classification for the urban region of Hanoi city. Journal of Sciences of the Earth, 33(4), 690-694 (in Vietnamese).Bui Van Duan, Ha Thi Giang, Nguyen Anh Duong, and Pham Dinh Nguyen, 2015. About factors related to the occurrence of earthquakes in the Song Tranh 2 hydropower area in period 2011-2014. Journal of Sciences of the Earth, 37(3), 228-240 (in Vietnamese).Building Seismic Safety Council, 2015. Recommended Seismic Provisions for New Buildings and Other Structures, Part 1: Provisions, Part 2: Commentary. Report No. FEMA P-1050-1, Federal Emergency Management Agency, Washington, D.C., 515p.CEN, 2004. EN 1998-1:2004, Eurocode 8: Design of structures for earthquake resistance - Part 1: General rules, seismic actions and rules for buildings. European committee for standardization, Brussels, Belgium.Cat Nguyen Hung et al., 2009. Seismic microzoning of Ho Chi Minh city. Final report of scientific research funding program supported by Ho Chi Minh City Goverment (in Vietnamese).Imai, T., 1977. P and S wave velocities of the ground in Japan. Proceeding of IX International Conference on Soil Mechanics and Foundation Engineering, 2, 127-132.International Code Council, 2009. 2009 IBC International Building Code, Country Club Hills, Illinois, 730p.Lee, C. T. and B. R. Tsai, 2008. Mapping VS30 in Taiwan. Terr. Atmos. Ocean. Sci., 19, 671-682, doi: 10.3319/TAO.2008.19.6.671(PT).Nguyen Anh Duong, T. Sagiya, F. Kimata, D. T. Tran, Q. H. Vy, C. C. Duong, X. B. Nguyen, and D. X. Nguyen, 2013. Contemporary horizontal crustal movement estimation for northwestern Vietnam inferred from repeated GPS measurements, Earth Planets Space, 65(12), 1399-1410, doi:10.5047/eps.2013.09.010.Nguyen Hong Phuong and Pham The Truyen, 2014. Probabilistic seismic hazard assessment for the South Central Vietnam. Vietnam J. Earth Sci., 36(4) 451-461.Nguyen Ngoc Hoa (editor), Duong Van Cau, Dang Ngoc Phan, Doan Sinh Huy, Hoang Ngoc Ky, Le Minh Thuy, Nguyen Van Quang, Truong Cong Duong, 1995. Geological and mineral map of Vietnam on a scale of 1:200.000 (Ho Chi Minh city sheet; C 48 - XI). Geological Survey of Vietnam, Hanoi (in Vietnamese).Nguyen Sinh Minh, Pham Dinh Nguyen et al., 2014. Seismic hazard assessment for the expanded Hanoi city, establishing of detail seismic zoning map for Ha Dong, Son Tay, Hoa Lac areas by scaled 1:25.000, building of database of ground motion features according to the above maps. Final report of scientific research funding program supported by Hanoi City Goverment (in Vietnamese).Petersen, M., Stephen Harmsen, Charles Mueller, Kathleen Haller, James Dewey, Nicolas Luco, Anthony Crone, David Lidke, and Kenneth Rukstales, 2007. Documentation for the Southeast Asia Seismic Hazard Maps. Administrative Report September 30, 2007, U.S. Geological Survey, Reston, Virginia.Phan Trong Trinh, 2012. Neo-tectonics and contemporary geodynamics in Vietnam sea area and adjacency. Publishing House for Science and Technology, Hanoi, 330p (in Vietnamese).Phan Trong Trinh, Ngo Van Liem, Nguyen Van Huong, Hoang Quang Vinh, Bui Van Thom, Bui Thi Thao, Mai Thanh Tan, Nguyen Hoang, 2012. Late Quaternary tectonics and seismotectonics along the Red River fault zone, North Vietnam. Earth-Science Reviews, 114(3), 224-235.Phan Trong Trinh, Hoang Quang Vinh, Nguyen Van Huong, Ngo Van Liem, 2013. Active fault segmentation and seismic hazard in Hoa-Binh reservoir, Vietnam. Cent. Eur. J. Geosci, 5(2), 223-235.Romero, S., and Rix, G.J., 2001. Regional Variations in Near-Surface Shear Wave Velocity in the Greater Memphis Area. Engineering Geology 62, 137-158.Simons, W. J. F., A. Socquet, C. Vigny, B. A. C. Ambrosius, S. Haji Abu, Chawat Promthong, C. Subarya, D. A. Sasito, S. Matheussen, P. Morgan, and W. Spakman, 2007. A decade of GPS in Southeast Asia: Resolving Sundaland motion and boundaries, J. Geophys. Res., 112, B06420, doi:10.1029/2005JB003868.Thompson, E.M and Wald D.J., 2012. Developing VS30 Site-Condition Maps by Combining Observations with Geologic and Topographic Constraint. The 15th World Conference on Earthquake Engineering: September 24-28, 2012, Lisbon, Portugal. USGS Publications Warehouse.Toro, G. R., Abrahamson, N. A. and Schneider, J. F., 1997. Engineering Model of Strong Ground Motions from Earthquakes in the Central and Eastern United States. Seismological Research Letters, 68(1), 41-57.Tran Thi My Thanh, Nguyen Le Minh, Vi Van Vung and Kojiro Irikura, 2014. Values for peak ground acceleration and peak ground velocity using in seismic hazard assessment for Song Tranh 2 hydropower region. Vietnam J. Earth Sci., 36(4), 462-469.Tran Thi My Thanh, Vi Van Vung, Hiroe Miyake and Kojiro Irikura, 2015. Simulated fround motion of the earthquake on Octorber 22nd, 2012, M4.6 at Song Tranh 2 dam area. Journal of Sciences of the Earth, 37(3), 241-251 (in Vietnamese).Vietnam Construction Code TCVN 9386:2012, 2012. Design of structures for earthquake resistances. Hanoi, 288p (in Vietnamese).Vu Trong Tan et al., 2010. Application of seismic borehole methods and establishing the calculating procedure of elastic parameters to serve for foundation structures and seismic resistant construction in Ho Chi Minh City and neighboring provinces. Final report of R-RD scientific research funding program supported by Ministry of Natural Resources and Environment (in Vietnamese).Wald, D. J. and Trevor I. Allen, 2007. Topographic Slope as a Proxy for Seismic Site Conditions and Amplification. Bull. Seism. Soc. Am., 97(5), 1379-1395.Wills, C.J. and Clahan, K.B., 2006. Developing a Map of Geologically Defined Site-Condition Categories for California. Bull. Seism. Soc. Am., 96(4A), 1483-1501.Yong, A., Hough, S.E., Abrams, M.J., Cox, H.M., Wills, C.J., and Simila, G.W., 2008. Site Characterization Using Integrated Imaging Analysis Methods on Satellite Data of the Islamabad, Pakistan, Region. Bull. Seism. Soc. Am., 98(6), 2679-2693.Yong, A., Hough, S.E., Iwahashi, J., and Braverman, A., 2012. A Terrain-Based Site-Conditions Map of California with Implications for the Contiguous United States. Bull. Seism. Soc. Am., 102(1), 114-128

Possibility of reservoir-triggered earthquake occurrence in the Huoi Quang and Ban Chat hydropower dam area

The possibility of reservoir-triggered earthquake occurrence in the Huoi Quang and Ban Chat hydropower dam area has been assessed based on studying and analyzing the relationships between the reservoir-triggered earthquake occurrence and the following factors: (1) the types of rocks underlying the reservoir; (2) the oscillating reservoir loads on faults in the reservoir area; (3) the incremental stress caused by reservoir loads; (4) the slip tendency of faults in the reservoir area; and (5) the Coulomb stress change of faults in the reservoir area. The results show that these factors have interactive effects and simultaneously contribute to the favorable conditions for reservoir-triggered earthquake occurrence. The Huoi Quang and Ban Chat hydropower reservoirs are located in the area of moderate seismicity; however, with the favorable conditions due to these five factors, reservoir-triggered earthquakes can possibly occur. If reservoir-triggered earthquakes occur, they will be concentrated around the Ban Chat hydropower dam area within a radius of 11 - 12 km and at a depth of about 6 ± 1 km

Effect of the Cultivation Technology on the Yield of Paddy Straw Mushroom (Volvariella volvacea)

The edible paddy straw mushroom Volvariella volvacea (Bull. ex F.) Singer has high nutritional and medicinal values. They are grown on a wide variety of agricultural byproducts using different several methods. The result of this present study showed that type of bed and cultivation condition (outdoor/indoor) had effects on the yield of paddy straw mushrooms grown on the spent oyster mushroom sawdust. The treatment of circular compact bed under indoor cultivation condition (CYIC) had the best yield and biological efficiency (B.E.) with 2,119.2 g/bed and 14.5%, respectively, followed by the treatment of conventional bed under outdoor cultivation condition (COOC) with the yield and B.E. of 1,935.5 g/bed and 13.2%, respectively, but the lowest yield and B.E. were observed in the treatment of conventional bed under indoor cultivation condition (COIC) with 1,226.1 g/bed and 8.4%, respectively. Paddy straw mushrooms cultivated on spent oyster mushroom sawdust should be proper in both outdoor and indoor conditions by conventional and circular compact methods as well. However, in indoor conditions, paddy straw mushrooms should be grown in a circular compact bed to ensure the temperature of the bed is suitable for the mushroom growth

Damage detection for a cable-stayed Bridge under the effect of moving loads using Transmissibility and Artificial Neural Network

Artificial Neural Network (ANN) has been widely used for Structural Health Monitoring (SHM) in the last decades. To detect damage in the structure, ANN often uses input data consisting of natural frequencies or mode shapes. However, this data is not sensitive enough to accurately identify minor structural defects. Therefore, in this study, we propose to use transmissibility to generate input data for the input layer of ANN. Transmissibility uses output signals exclusively to preserve structural dynamic properties and is sensitive to damage characteristics. To evaluate the efficiency of the proposed approach, a cable-stayed bridge with a wide variety of damage scenarios is employed. The results show that the combination of transmissibility and ANN not only accurately detect damages but also outperforms natural frequencies-based ANN in terms of accuracy and computational cost

Damage detection for a cable-stayed Bridge under the effect of moving loads using Transmissibility and Artificial Neural Network

Artificial Neural Network (ANN) has been widely used for Structural Health Monitoring (SHM) in the last decades. To detect damage in the structure, ANN often uses input data consisting of natural frequencies or mode shapes. However, this data is not sensitive enough to accurately identify minor structural defects. Therefore, in this study, we propose to use transmissibility to generate input data for the input layer of ANN. Transmissibility uses output signals exclusively to preserve structural dynamic properties and is sensitive to damage characteristics. To evaluate the efficiency of the proposed approach, a cable-stayed bridge with a wide variety of damage scenarios is employed. The results show that the combination of transmissibility and ANN not only accurately detect damages but also outperforms natural frequencies-based ANN in terms of accuracy and computational cost

Assessment of impacts of utilization on water resources in the basin of trans-boundary Red river system

The Red river system is the large trans-boundary river system, there has been no united system of hydrology stations as well as integrated plan for the water use and management in the whole basin. The trend of water resources change in the Red river system basin has been assessed on the basic of statistic analyses of data observed during the studies, especially in the time when the exploitation of water resources has been intensified for the multisectoral development. This paper shows some of the results from considerations of the water use in the highlands that is influential in water resources in the Red river system basin and the planned reservoirs which are built in the basin of Red river system. The results include the assessment of the state and trend of water resources in the Red river system basin, the trend of water level lowering in the lowlands and its impacts

Status Poles and Status Zoning to Model Residential Land Prices: Status-Quality Trade off Theory (Short Paper)

This study describes an approach for augmenting urban residential preference and hedonic house price models by incorporating Status-Quality Trade Off theory (SQTO). SQTO seeks explain the dynamic of urban structure using a multipolar, in which the location and strength of poles is driven by notions of residential status and dwelling quality. This paper presents in outline an approach for identifying status poles and for quantifying their effect on land and residential property prices. The results show how the incorporation of SQTO results in an enhanced understanding of variations in land / property process with increased spatial nuance. A number of future research areas are identified related to the status pole weights and the development of status pole index

Synthesis, crystal structure and Hirshfeld surface analysis of 4-[3-(4-hy-droxy-phen-yl)-4,5-di-hydro-1H-pyrazol-5-yl]-2-meth-oxy-phenol monohydrate.

In the title pyrazoline derivative, C16H16N2O3·H2O, the pyrazoline ring has an envelope conformation with the substituted sp 2 C atom on the flap. The pyrazoline ring makes angles of 86.73 (12) and 13.44 (12)° with the tris-ubstituted and disubstituted benzene rings, respectively. In the crystal structure, the mol-ecules are connected into chains running in the b-axis direction by O-H⋯N hydrogen bonding. Parallel chains inter-act through N-H⋯O hydrogen bonds and π-π stacking of the tris-ubstituted phenyl rings. The major contribution to the surface contacts are H⋯H contacts (44.3%) as concluded from a Hirshfeld surface analysis

Depression, anxiety and stress among healthcare workers in the context of the COVID-19 pandemic: a cross-sectional study in a tertiary hospital in Northern Vietnam

IntroductionThe outbreak of coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) had significant effects on the mental well-being in general, particularly for healthcare professionals. This study examined the prevalence of depression, anxiety, and stress, and identified the associated risk factors amongst healthcare workers during the COVID-19 outbreak in a tertiary hospital located in Vietnam.MethodsWe conducted a cross-sectional study at a tertiary-level hospital, where the Depression Anxiety and Stress Scale 21 (DASS-21) web-based questionnaire was employed. We analyzed the determinant factors by employing multivariate logistic models.ResultsThe prevalence of depression, anxiety, and stress symptoms were 19.2%, 24.7%, and 13.9%, respectively. Factors such as engaging in shift work during the pandemic, taking care of patients with COVID-19, and staff’s health status were associated with mental health issues among health professionals. In addition, having alternate rest periods was likely to reduce the risk of stress.ConclusionThe prevalence of mental health problems in healthcare workers during the COVID-19 pandemic was relatively high. Having resting periods could potentially mitigate the development of stress among health professionals. Our findings could be taken into account for improving mental health of the health professional population