1. introduction droughts are long-term phenomena that can affect large areas and cause severe downturn in economic and social activities. recognizing this phenomenon, its features and properties, knowledge of facilities, capabilities and talents of areas and providing short and long term solutions leads to the effort of the surface water resource managers to prepare for drought mitigation. the ...

1. introduction as the pressure of porous water increases in sand soils and saturated loose layers during an earthquake, the soil tendency to reduce its own volume leads to a decrease in the soil’s multifaceted tension. this way, the shear strength of the soil strongly decreases and comes close to zero. this phenomenon is called liquefaction. soil liquefaction is the cause of much destruction o...