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The earthquake size distribution (b-value) is a significant factor to recognize the seismic activity, seismotectonic, and seismic hazard assessment. In the current work, the connection of the b-constant value with the focal depth and mechanism was studied. The effect of the study scale (global, regional and local) on the dependence of b-value on the focal mechanisms was investigated. The database is quoted from the Global Centroid Moment Tensor catalog. The selected earthquakes are the shallow normal, reverse and strike-slip events. The completeness magnitude (Mc) is 5.3. The maximum likelihood method is utilized to compute the b-value. The obtained results show that the b-value is decreasing with depth to range 10-20 km, then increases to the depth of 40km. The turning point of b-value (increasing of b-value) locates at the depth of the transition brittle-ductile zone. Globally and regionally, low, moderate, and high b-values are associated with reverse, strike-slip, and normal focal mechanisms, respectively, while locally, the relation between b-values and focal mechanisms shows different association trends, such as low, moderate, and high b-values are associated with normal, strike-slip, and reverse focal mechanisms and so on.

A study was conducted to estimate the Irrigation Water Quality Index (IWQI) for Habbaniya Lake in central Iraq for irrigation purposes. The samples were taken at sixteen stations in October 2019. Studied samples were examined for ten Physico-chemical parameters Hydrogen Number (pH), Electrical Conductivity (EC), Temperature (T °C), Total Dissolved Solids (TDS), Total Hardness (T.H.), Turbidity (NTU), Sodium Absorption Ratio (SAR), Na+, Cl−, and HCO3 −. The results showed that 68.75% of the study water samples fall within the low restriction category (LR) irrigation water in eleven stations (which is dominant in all parts) and 25% of the search region falls under the no restriction category (NR) irrigation water in four stations (which is dominant in the northwestern part at station 5-8). Meanwhile, a small part of the study area represents 6.25% of the water samples is classified as a moderate restriction (MR) irrigation water in one station (in the central part). Accordingly, these categories are suitable to use only with the soil having low to moderate permeability with a plant of some kind for specified tolerance of moderate salts content. The IWQI is homogeneous and suitable for irrigation in all parts, especially the northwestern part which represents the entrance waters through Warar Canal that fed principally from the Euphrates River.

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Seismicity of Iraqi western desert and surroundings was investigated using a complete and unified magnitude earthquake catalog covering the interval from 1900 to 2017. A marked rise in number of the events in the study area was observed after the year 2000 compared to the previous years. The magnitude of majority of the recorded events ranged from 2 to 3.5 Mw. The value of b-constant in frequency-magnitude relation is 0.7. The epicentral distribution shows that the western desert is aseismic to very low seismicity area compared to the surrounding regions. The epicenters were clustered in five seismogenic zones. The focal depths division of the events exhibits that majority of the earthquakes occur in the upper crust. A causal relation may be between the study area seismicity and the zones of weakness and /or stress condensation at the fault intersections.