Seismic hazard assessment of the urban area of Ambato, Ecuador, in deterministic form

Seismic microzonation of the urban area of Ambato, Ecuador, was done in 2018 in a probabilistic and a deterministic manner. This type of calculation is presented in the first part of the article. For this purpose, three geologic faults and three strong-motion equations were considered. For each geologic fault, recurrence periods are determined using two methods. It is seen that a magnitude 6.3 earthquake associated with the blind faults traversing Ambato may occur in 80 to 100 years, and one of magnitude 6.5 in the next 300 years. Geophysical and geotechnical studies of the urban area of the city of Ambato are presented. These permitted the acquisition of curves with the same period of soil vibration and equal speed of the shear wave in the first 30 m, plus the classification of soils of the city. Later, six models of strong soil movements were considered and horizontal acceleration spectra of the soil were obtained in a mesh of points separated every 500 m, for each soil profile. Average spectra were found for soil profiles C, D and E when making comparisons with the spectra found in the 2018 study. Based on the results of the present study and those from 2018, new spectral forms are proposed for the urban area of the city of Ambato (called spectral envelopes) and compared to spectra reported by seismic regulations in force in Ecuador (NEC-15).

Determination of Swell Potential of Soils using Cole in Panyam, North – Central Nigeria

Swell potential of soils from parts of Panyam, North – Central Nigeria were investigated covering 72 square kilometres within latitudes N9021′ and N9026′ and longitudes 9011′E and 9015′30″E. With the increase of civil engineering constructions and the scramble for limited portions of competent soils for such constructions, there is an urgent need in a developing nation to study and characterize such soils based on its geotechnical properties. The geotechnical studies include twenty soil samples taken within the 1.5m depth with the aim of determining the swell potential in order to give appropriate guide to any civil engineering design and construction. The direct method of soil analysis which is the coefficient of linear extensibility (COLE), which ranges from 0.02–0.17 was used for the study. COLE Values greater than 0.06, were considered to be critical for most civil engineering design and constructions. Most of the samples studied were considered not safe for bungalows and some infrastructure without proper safety measures carried out to improve upon it.

Zonificación geotécnica de los suelos de la ciudad de Valledupar mediante utilización de un SIG

Se realizó la zonificación geotécnica de los suelos en la ciudad de Valledupar (cesar) mediante la recolección de datos en diferentes laboratorios de suelos, además de la obtención de muestras por parte de los investigadores. Con dicha información se creó la base de datos necesaria para la investigación. Se obtuvieron gráficos para las diferentes características. Los principales tipos de suelos encontrados fueron SC y SM, así como también suelos GW que se presentan en todas las comunas de la ciudad. El nivel freático se encontró a partir 1,2 metros de profundidad. Desde el punto de vista del RAS, la presente investigación contiene la información necesaria para los estudios previos que dicho reglamento requiere. Se define que la ciudad puede soportar cimientos para edificación de más de 10 niveles siendo las capacidades de carga a los 4 metros superior a los 50 ton/m2, en zonas con altos porcentajes de grava, estas áreas serán las de mayor incidencia a la hora de aumentar la cobertura de redes de acueducto y alcantarillado. The geotechnical zoning of the soils was carried out in Valledupar (Cesar) by collecting data in various soil laboratories and obtaining samples. The research database was created. The types of soils found were SC, SM and GW identified in all the communes of the city. The water table was found from a depth of 1.2 meters. The document contains the necessary information for geotechnical studies of the area where it is concluded that the city can support building foundations of more than 10 levels, in areas with high percentages of gravel, these areas will be the ones with the highest incidence when increasing coverage of aqueduct and sewerage networks. It is the first geotechnical research study through geographic information models in Valledupar; This indicates the generation of a technical and bibliographic resource for quick consultation

Qualifying the geotechnical and hydrological characteristic of the Bandawaya stream valley – Northern Iraq

In northern Iraq, countless non-abuse stream valleys can be used to store water for a variety of purposes; domestic, supplementary irrigation, and recharging groundwater. Bandawaya is one of the stream valleys, which form the first perspective has excellent quality. The location of the suggested dam has been evaluated by hydrological and geotechnical studies. Geotechnical studies included measurement of all the parameters related to the rock mass classification for evaluation based on four classification systems, which are the Q-System, the rock mass rating (RMR), the geological strength index (GSI), and the rock mass index (RMi). The classification results indicated that the rocks of the valley are good for constructing a dam on them, with some weak zones that may affect the integrity of the dam, which the study recommended treating before starting the construction of the dam. According to preliminary studies on different dam’s heights the qualification demonstrates an excellent choice of the site. Four stream orders are recognized, dendritic pattern in the southern part of the watershed, and trellised in the northern part. Three heights assumed to the proposed dam 450, 460, 470 m a.s.l. with 640,764; 3429,787; 8,590,763 m3 storage capacity respectively. According to the Q-System, the RMR, the GSI, and the RMi, the rock mass of the study area is evaluated. The findings illustrate the excellent selection by geotechnical, hydrological, and engineering features of the dam place.

Engineering Geological and Geotechnical studies of Taprang landslide, west-central Nepal: An approach for slope stability analysis

Detailed investigation of Taprang landslide was carried out in order to understand the surface, subsurface lithological information and physical properties of soil by using multi-disciplinary methods such as engineering geological, geophysical and geotechnical studies for the determination of factor of safety for slope stability analysis. Geological study was carried out by detail mapping of surface geology, soil condition, properties of bedrock and its discontinuities. The geophysical survey (Electrical Resistivity Tomography-ERT) were carried out to know the electrical resistivity of soil for identifying the groundwater table and hence slip surface of the landslide. Geotechnical analysis such as grain size analysis, liquid limit and direct shear test were carried out in order to evaluate soil classification, moisture content, cohesion and the angle of internal friction of soil for knowing the strength the soil. These soil parameters indicate the soil is very low strength. The combination of these results were used for calculating the factor of safety (FoS) by Limit Equilibrium Method (LEM) proposed by Bishop and Janbu methods. The result of factor of safety in the Taprang landslide demonstrates that the slope become stable in drained (dry) condition, remain ultimate stage in undrained (wet) condition and finally failure occurs if applied the seismic load in both drained and undrained conditions.

CHIRP-ENGINEERING SEISMIC METHOD FOR EXPLORING SEABED AND UNDERWATER STRUCTURES: OFF-SHORE WESTERN ANATOLIA

CHIRP systems are widely used in seabed sediment classification, submarine faults, positioning of marine engineering structures, pipeline geotechnical studies, platform and well area assessments, archaeological and environmental impact assessments. The resolution of the system is in the order of decimeter. In this study, the characteristics of submarine active faults, buried faults, seabed and underlying layers in the region were analyzed and interpreted by CHIRP data collected off-shore Seferihisar, Teke Peninsula and Alaçatı.