Deaggregation of Probabilistic Ground Motions for Selected Jordanian Cities

Probabilistic Seismic Hazard Analysis (PSHA) approach was adopted to investigate seismic hazard distribution across Jordan. Potential sources of seismic activities in the region were identified, and their earthquake recurrence relationships were developed from instrumental and historical data. Maps of peak ground acceleration and spectral accelerations (T=0.2 and T=1.0 sec.) of 2% and 10% probability of exceedance in 50 years were developed. This study deaggregated the PSHA results of 2% and 10% probability of exceedance in 50 years results of twelve Jordanian cities to help understand the relative control of these sources in terms of distances and magnitudes. Results indicated that seismic hazard across these cities is mainly controlled by area sources located along the Dead Sea Transform (DST) fault system. Cities located at short distances from the DST tend to show close deaggregation behavior. Some discrepancies may exist due to the proximity or remoteness of these cities relative to the DST seismic sources and local seismicity. The modal or most probable distance distribution indicated that the distance to the earthquake which contributes most to the hazard at each city is mainly controlled by shaking along faults associated with near seismic area sources. The influence of adjacent seismic sources to the seismic hazard of each city is more evident for the long period spectral acceleration. Distant sources, such as the eastern Mediterranean, Cyprus, Suez and the southern region of the Gulf of Aqaba are relatively low, but can not be neglected due to the intrinsic uncertainties and incomplete seismic data

Impact of a domestic wastewater treatment plant on groundwater pollution, north Jordan

An assessment of groundwater pollution in the area surrounding a domestic wastewater treatment plant in northern Jordan has been carried out. Groundwater in the study area is classified as alkaline earth water with increased portions of alkalis and prevailing chloride, tending to shift to alkaline water with the dominance of chloride. This trend indicates mixing between the two end members of fresh Ca2+-HCO3 - water and saline Na+-Cl - water. Spatially, the highest concentrations of the hydrochemical parameters were found in close proximity of the Al Ramtha Wastewater Treatment Plant (RWWTP). Nitrate, which is the most common human-introduced pollutant into groundwater resources, was used to evaluate pollution of phreatic groundwater in the study area. Its concentration (as NO3 �) ranges between 1 mg/L and 366 mg/L, with an average of 79 mg/L. A total of 71% of the samples present nitrate concentrations exceeding the threshold value for anthropogenic sources (20 mg/L), and more than 50% in excess of World Health Organization (WHO) standards for drinking water (50 mg/L). The most important factors affecting the magnitude of groundwater pollution are depth to groundwater table, aquifer transmissivity (hydraulic conductivity), lineaments density, and distance from treatment plant with calculated correlation coefficients of -0.51, 0.65, 0.70, and -0.75 to nitrate concentration, respectively.Se llevó a cabo una evaluación de la contaminación del acuífero en el área que rodea una planta de tratamiento de aguas residuales domésticas en el norte de Jordania. El agua de este acuífero se clasifica como alcalina-térrea con proporciones de álcalis que se incrementan, prevaleciendo los cloruros, y con tendencia a cambiar a agua alcalina con predominio de cloruros. Esta tendencia indica una mezcla entre dos miembros de agua Ca2+-HCO3 - y agua salina de Na+-Cl -. Espacialmente, las concentraciones más altas de los parámetros hidroquímicos se encontraron en las cercanías de la planta de tratamiento de aguas residuales Al Ramtha (RWWTP, por sus siglas en inglés). El nitrato, que es el contaminante más común introducido por el hombre en los recursos acuíferos, fue usado para evaluar la contaminación del acuífero en el área de estudio. Su concentración (como NO3 �) varía entre 1 mg/L y 366 mg/L, con un promedio de 79 mg/L. Setenta y un porciento de las muestras presenta concentraciones que exceden el valor de umbral para fuentes antropogénicas (20 mg/L), y más del 50% excede los estándares para agua potable (50 mg/L) según la Organización Mundial de la Salud (OMS). Los factores más importantes que afectan la magnitud de la contaminación de los acuíferos son la profundidad del nivel freático, la transmisividad del acuífero (conductividad hidráulica), densidad de alineamientos y distancia de la planta de tratamiento, con coeficientes calculados de correlación con la concentración de nitratos de -0.51, 0.65, 0.70 y -0.75, respectivament